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The intention of this paper is to review of some recent innovative novelties about paper and board pigment coating raw materials. First an overview is given of “traditional” coating raw materials and the coating process. Then new starch based pigments and binders as well as novel plastic pigments are reviewed regarding their effect on coated paper properties. Finally it is concluded that further innovations and research are needed.

Present paper reports investigations carried on corrosion behaviour of mild steel in effluents collected from paper mill treatment plant. For this purpose, effluent was collected from after primary and secondary treatment stages. Mild steel samples were exposed to these effluents for duration of six months. The corroded samples were analysed for weight loss and extent of localised corrosion. Electrochemical polarization tests like open circuit potential (OCP), tafel plot and anodic polarization were also performed to estimate corrosion rate, polarization resistance and localized corrosion parameters in the studied system. The extent of corrosion attack has been correlated with effluent parameters namely pH, electrical conductivity (Ec), total suspended solids, total dissolved solids, chemical oxygen demand, biochemical oxygen demand, chloride content, colour and sulphate.

In the process of recycling phosphate ore processing wastewater, the accumulation of inorganic ions and the flotation reagents have a great influence on the flotation performance when they reach to a certain concentration. This paper studied the effect of Ca2+, Mg2+, SO42- and PO43- on the reverse flotation of phosphate ore through the single factor experiment. The experimental results show that Ca2+, Mg2+ and PO43- have less effect on the flotation performance, and that a certain amount of PO43- in the ore pulp can reduce the dosage of acid and improve the flotation result. SO42- has a significant effect on the reverse flotation of phosphate ore and the concentration of SO42- should be controlled under 1 g/L in the backwater utilization.

Using novel dual cathode/electro/Fe2+/S2O82-system to treat pickle sauerkraut wastewater, the paper investigates the influencing factors (S2O82-dosage, Fe2 +dosage, current density, Wastewater pH, electrode plate distance) of the organic matters removal and the treatment effect. Test results show that the degree of various factors influence on COD removal of sauerkraut wastewater is different. The COD removal is little effected by pH, while largely effected by current density, dosage of Fe2 +and S2O82-dosage. Under the optimum experiment conditions, current density for 30mA/cm-2, dosage of Fe2 +for 8mmol/L, S2O82-dosage for 12 mmol/L, electrode plate distance for 2 cm and pH=6, sixty minutes electrolysis, wastewater removal rate reach up to 92.6%. These results suggest that this electrochemical oxidation process by dual cathode/electro-Fe2+-S2O82-system might provide an alternative for the degradation of pickle sauerkraut wastewater.

Organosilicon compound are widely used in pulping and papermaking industry. The quality and capability of paper sheet are distinctly affected by the use of organosilicon. The application of organosilicon used as softening agent, defoamer agent, strengthening agent were introduced one by one in this paper.

The purpose of the present study was to investigate the ability ofMicrobacterium liquefaciensstrain MNSH2-PHGII-2, isolated from a Mexican silver mine, for removing Ni and V from spent catalyst at 80% (w/v) pulp density in a glass-column system at laboratory conditions. Firstly, microbial culture was adapted to spent catalyst at 0.1% (w/v) in liquid culture then, it was assayed by its ability to remove Ni and V from a spent catalyst in a glass-column system. Spent catalyst was packed at 80% (w/v) pulp density and inoculated at 20% (3x108CFU/ml); air was supplied at 80 ml/min and then incubated at 30°C during 14 days. Parameters such as microbial growth, pH, Ni and V residual concentrations, in catalyst, were determined at days 7 and 14. The result showed thatMicrobacterium liquefaciensstrain MNSH2-PHGII-2 in the glass-column system was able to remove 1007.4 mg/kg of Ni while V was removed at an extent of 5360.5 mg/kg. Microbial removal for other metals in catalyst was non-significant, that indicated the specificity ofMicrobacterium liquefaciensto remove Ni and V.

Peru is mining country with a great diversity of mineral resource. The high grade ores are declining, and there is a need to implement new techniques for recycling metals (Cu, Au, Zn, Pb, etc) from low-grade ores. In order to answer this question, the bioleaching of copper from sulphide ore (FeS2 45.30%, CuFeS2 1.90%, ZnS 8.90%, FeAsS 13.12%, PbS 3.69%) was evaluated with different concentrations of Fe2+ using an iron-oxidizing native microbial consortium.The samples were collected from drainage acid mine (4100 m.a.s.l.) located in the south of Huancavelica region and the sample of ore from middle Huaraz region (3200 m.a.s.l.). Microorganisms were isolated in 9k medium at pH 1.8, 22oC. Bioleaching test were performed in two consecutive steps to 150 rpm at 22oC, monitoring pH, ORP (mV). Assays varying the concentration of Fe2+ (0 mM – 53 mM) were performed with a pulp density of 1% and 2% at each step, and with an inoculum 10% (v/v) to a microbial concentration of 108 cel/mL.We isolated a microbial consortium after 8 weeks with presence of bacteria Acidithiobacillus ferrooxidans-like. In assays, copper was solubilized. The microbial concentration in the tests was (2x107- 4x107cel/mL). In the first stage, the test with 21 mM Fe2+ recovered 62% copper. In the next step, with the bacterial concentration of the first step, bioleaching time is reduced by 22% for copper recovery (63%) in absence of Fe2+.With these data, we observed that the addition of iron is not necessary in a stage adaptation when the mineral contain iron.

The high-speed blanking process applying precision progressive die represents the one of the highest level of today’s stamping technology, mainly is used for the production of the ultra-thin, small, complex electronic components. An orthogonal experiment scheme with three factors (including blanking clearance, surface roughness of the die, stamping speed) was established in this paper based on the actual production. The high-speed blanking process experiment applying precision progressive die was carried out base on this scheme. The quality of the shearing edging of blanking parts was used to evaluate the different influence degree of three factors. The result showed that the surface roughness of the die affected the quality of the shearing edging more than that of the other two. The higher the die surface accuracy, the better the quality of the shearing edging. The result also showed that the high speed can reduce the quantity of the burr of the blanking of the ultra-thin sheet metal.

The study on potential-controlled flotation test of differential flotation process was carried out in the light of the change of a certain ore properties. The test used self-developed EMZ-91, as well as conventional collectors of ethyl thio carbamate and butyl xanthate for the flotation of copper, lead and zinc ores respectively, in which the copper sulfate was used as the activator of zinc mineral. The new differential flotation process, which is using lime to regulate pulp potential, produced the copper concentrate grading 27.18% copper at 73.37% recovery, the lead concentrate grading 66.00% lead at 63.00% recovery, and the zinc concentrate grading 55.27% zinc at 87.69% recovery.

In this paper, advanced Fenton-hydroxide precipitation process was proposed to remove synthetic wastewater containing CrEDTA. This process can not only remove chromium, but also reduce COD values. Parameters affecting chromium removal are discussed. At optimum conditions, the chromium removal efficiency attained 87%. Advanced Fenton-hydroxide precipitation process appears a promising and effective method for the treatment of strong stability complex heavy metal containing wastewaters.

This study investigated the flotation in sodium dodecyl benzene sulfonate system, the effects of phytic acid on talc flotation mechanism, then proposed a new flowsheet to handle this kind talc ore, namely “one roughing-three cleaning-one scavenging’’. The closed-circle flotation test in laboratory can obtain a concentrate with the SiO2 and CaO grade of the concentrate is 61.87% and 0.60%, the SiO2 recovery is 72.59%, removal rate of tremolitei is 95.85%. This paper improved the economic value of the talc containing asbestos, laid the foundation of industrial applications.

The produced and extraction process of pyritic would generate a large amount of pyritic mineral processing solid waste. This kind of waste can lead to land occupation, and contaminate the local water, air and soil. Therefore, in this paper, Thiobacillus ferrooxidans and Thiobacillus thiooxidans are used to deal with the pyritic mineral processing solid waste. The particles, catalysts and bioleaching products between microorganism and pyritic mineral processing solid wast were studied. It is indicated that the microorganism growth and the heavy metals leaching efficiency involve biological and chemical interactions. The experimental results suggested that the T.t was best to bioleach the pyritic mineral processing solid waste, and the efficiency of T.f was worse than that of T.t. The leaching effect of mixed bacterias of T.t and T.f fell in between, the leaching rate would decrease when the pulp density increased. The micro-morphology of bacteria was observed by SEM detector, the single cellular dimension of bioleaching bactreia was about (1~2) μm × (0.2~0.5) μm.

Many vessels capsized in the passed few years when carry nickel ore, this make many shipowners and crewmembers fear to carry nickel ore . This paper based on the special properties of nickel ore, analysis the root cause why nickel ore are easy to liquefaction when carried on board, demonstrated nickel ore's liquefaction produce large amount of free surface and make vessel loss stability and cause harmful to vessels and crewmembers, summarized additional difficulty vessel encountered when carry nickel ore, based the requirements from IMSBC Code point out the key point of safe transport nickel ore is keep its moisture content below TMP, also represent some useful precautions on nickel ore safe shipment.

According to the properties of the zinc leach residue, the recoveries of lead and zinc from residue have been studied in this paper. At first, ZnO.Fe2O3 was recovered by magnetic separator, and the grade of zinc concentrate is 14.89% and the recovery is 65%.Next step, zinc sulfide was recovered by flotation, and the grade of zinc concentrate is 29.65% and the recovery is 29.65%.The last, the lead residue was recovered by flotation and the grade of lead concentrate is 17.21% and the recovery is 56.37%. The technology is very effective to enrich value metals, and realize utilization of resource protecting the environment.

Indirect bioleaching is a biotechnology that presents important advantages when apply to bioprocessing of zinc and zinc polymetallic concentrates such as high metals recovery, fast kinetic of 4-5 hours to get full metals extraction, sulphur oxidation to elemental sulphur (avoiding sulphuric acid generation, while pyrite mineral remains untouched), and use of conventional reactors (aeration is not required) and normal process equipments. On the other hand, the development of high-efficiency bioreactors for ferrous iron bio-oxidation based on flooded fixed-bed model has opened the way to succeed in the potential commercial application of this innovative bio-hydrometallurgical technology, being especially attractive to benefit zinc and lead bulk or polymetallic concentrates containing other valuable metals like silver. In addition, a great variety of concentrates is feasible to be processed, e.g. in the range of 15% to 60% Zn and Pb metals content. That aim, within European Biomine project, for the first time in biohydrometallurgy field, indirect bioleaching technology applied on Zn/Pb polymetallic concentrates has been demonstrated in continuous in an integrated pilot plant at Tecnicas Reunidas’ (TR) R&D Centre in Madrid (Spain) producing electrolytic SHG zinc plates. Overall zinc recovery in the integrated pilot facility after more than 300 operating hours has been above 95% thanks to the ability and good performance of the ZincexTM technology (solvent extraction and electrowinning), in which obtaining of SHG electrolytic zinc is fully guaranteed with high current efficiency (above 93%) and good deposit morphology. In definitive, a profitable marriage between indirect bioleaching process and ZincexTM technology has been successfully demonstrated in TR facilities at pilot plant scale, and main results of such integrated pilot plant operation are presented in this paper.

The paper “Bacterial succession in bioheap leaching” [1] initiated the search for methods to analyze the microbial dynamics in bioleaching industrial processes as a key to advancing commercial bioheap applications. “Chemical and physical conditions within bioheaps change radically from the time the bioheap is stacked and inoculated until bioleaching is completed.” The results from a comprehensive monitoring program by culturing and molecular techniques in an industrial bioleaching process for Run-of-mine (ROM) low grade copper sulfide ore in Chile will be summarized. The analysis of the compiled information permits an understanding of changes in microbial substrates availability, chemical and physical conditions. The impact of other aspects on microbiology, such as the mining programme and the industrial design are also considered. The bacterial succession in bioheap leaching solutions allowed the leaching cycle stages to be describe as: i) Acid conditioning and soluble copper releasing, ii) Chalcocite Bacterial leaching (ferrous oxidation); iii) Chalcocite Bacterial leaching (ferrous and reduced sulfur compounds –RSC- oxidation); iv) Bacterial leaching of sulphide minerals with higher rest potentials (pyrite and covellite ), v) Bacterial oxidation of remnant sulfide minerals and RSC.

Taking molybdenum tailings as the research object, the methods of recovering phlogopite on the base of comprehensive utilizations of other valuable minerals has been discussed. The best flotation condition includes that pulp density is 25%, the value of pH is 8.4, and the spindle speed of the batch flotation cell is 1850 r/min, sodium silicate is used as the silicate inhibitor, sodium oleate as collector, alkyl amine as the foaming agent. After cleaning and scavenging, the yield of the recovery and grade of concentrated phlogopite could be reached above 40% and 9.5%, and the yield of recovery and grade of scavenged phlogopite could be reached above 20% and 7.0%. The experimental research may provide the theoretical and experimental basis for phlogopite flotation from molybdenum tailings.

The effect of ZnO dosage, iron remover and the time duration of neutralization and iron-precipitation on iron removal percentage was investigated to find out the optimal parameters in the technique of ZnO pressurization, neutralization and iron removal, and the residual acid from pressurization lixiviation and neutralization was assayed by using ZnO ore to neutralize and remove iron from lixiviated mineral pulp containing residual acid 20 g/l by simulation of Zn concentrate pressurization and lixiviation in a 2 L autoclave, in order to simplify Zinc pressurization process. The result showed that when Zn lixiviation percentage is higher than 98 %, up to 99.74 % of iron in the lixiviation fluid could be precipitated and the lixiviated fluid contains iron at the level of 20 mg/l, meeting the requirement on pre-purification fluid. Keywords: Zinc Sulfide Concentrate; Pressurization and Lixiviation; ZnO Ore; Neutralization and Iron Precipitation

The research purpose is the change for acid pollution lateritic shearing strength indices and compressor characteristics indicial under different concentration of hydrochloric acid , differ curing time in text.The test result proven,acid pollution lateritic shearing strength indices and compressor characteristics indices population take on depress tide in company with hydrochloric acid concentration and curing horary Increase.

The useful minerals of Jinchuan high-grade copper and nickel suphfide ores were mainly nickel and copper, whose grade were respectively 1.42% and 1.01%. The content of MgO and SiO2, main gangue components, reached 57.89%. The key to improve the separation indexes of flotation concentrate was to inhibit the gangue minerals effectively, therefore, the effects of different kinds of regulators on Jinchuan high grade copper-nickel ores by flotation were studied. Considering the grade and recovery of concentrate comprehensively, the optimal regulator of mineral flotation was determined to be the combination of sodium hexametaphosphate and citric acid, and the dosage were 300g/t and 500g/t, respectively. After analyzing the mechanism of the two regulators, the combined reagents could reduce the isoelectric point of gangue minerals, decreasing the adsorption between gangue minerals and valuable minerals. In addition, the reagents were able to eliminate the activation of useless ions such as Ca2+ and Ni2+ on the gangue minerals and improve the ion composition of pulp, increasing the difference of floatability between gangue and useful minerals.

Cobalt, having many diverse and critical uses, is an essential metal in today's society. However, the recovery of cobalt is difficult due to its associated mineral characteristics. A biohydrometallurgical process has been developed for cobalt recovery from low grade refractory carrollite. After direct oxidation for 6 days, 96.51 % Co and 26.32 % Cu were extracted from the ore using a pulp density of 10 %. The bioleaching solution contained 22.62 gL-1 ferric iron while the concentration of cobalt was only 0.83 gL-1. Therefore, a goethite deironization process was then conducted. Different conditions, such as pH value, temperature, standing time and oxidant concentration were studied in detail. The results showed that when the pH value was 4.0, oxidation temperature was 70 °C, standing time was 1 h, and oxidant concentration was 8%, then the iron removal and the loss of cobalt were 99.9 % and 0.5 %, respectively. The goethite precipitate had good filterability. The sum recovery of cobalt in the whole extraction process attained more than 95 %. The biohydrometallurgy process for the recovery of cobalt has economic and environmental advantages over the other methods.

Solid waste from sulphuric acid production contains high concentrations of metals that are harmful if released to the environment. The purpose of this study was to evaluate the acid bioleaching of metals from a sample of pyritic ashes, consisting mainly of hematite. Bioleaching was tested in shake flasks and continuously stirred tank reactors (CSTR) inoculated with iron and sulphur oxidising acidophiles. Solubilisation of metals was mainly achieved through acid attack due to the formation of sulphuric acid by sulphur oxidising bacteria.

Methods for improving the treatment efficiency of a refractory gold-bearing sulphidic concentrate are proposed. These methods consist of the oxidation of the concentrate through a two-step process: a high-temperature ferric leaching step and a subsequent biooxidation step, which further involves the use of organic nutrients. The concentrate contained 34.7% pyrite and 7.9% arsenopyrite. The biooxidation of the concentrate (in a one-step process) was conducted at 45°C in bioreactors under continuous conditions. The pyrite and arsenopyrite oxidation levels after 240 hours were 60.2 and 92.0%, and the gold recovery level by cyanidation was 65.7%. The two-step process involved the leaching of the concentrate by a Fe3+-containing solution and the subsequent biooxidation of the leach residue. The pyrite andarsenopyrite oxidation levels after 240 hours of biooxidation were 65.7 and 94.1%, and the gold recovery level was 71.7%. The effect of an organic nutrient (yeast extract) on biooxidation during the two-step process was studied. The pyrite and arsenopyrite oxidation levels after 240 hours of biooxidation under mixotrophic conditions were 73.5 and 95.1%, and the gold recovery level was 77.9%. The effect of the organic nutrient on the microbial population was determined. Sulfobacillus thermosulfidooxidans and Acidithiobacillus caldus were the predominant microorganisms studied under both autotrophic and mixotrophic conditions. Archaeon Acidiplasma sp. MBA-1 was a minor component of the microbial community under autotrophic conditions but was one of the predominant microorganisms studied under mixotrophic conditions. The strain MBA-1 could oxidise both ferrous iron and elemental sulphur in the presence of yeast extract. These results suggest that the organic nutrient changed the composition and increased the activity of the microbial population. Thus, a two-step process with organic nutrients added during biooxidation may be considered an effective strategy for treating refractory pyrite-arsenopyrite concentrates.

Rapid technological advancement and the relatively short life time of electronic goods have resulted in an alarming growth rate of electronic waste which often contains significant quantities of toxic and precious metals. Compared to conventional chemical recovery methods, bioleaching has been shown to be an environmentally friendly process for metal extraction. In this work, gold bioleaching from electronic scrap material (ESM) was examined using batch cultures of the bacterium Chromobacterium violaceum which produces cyanide as a secondary metabolite. Gold was bioleached via gold cyanide complexation. The ESM was pretreated using nitric acid to dissolve the base metals (mainly copper) in order to reduce competition for the cyanide ion from other metals present in ESM. ESM was added to the bacterial culture after it reached maximum cyanide production during early stationary phase. Spent medium bioleaching using bacterial cell- free metabolites showed a higher gold recovery of 18%, compared to that of two-step bioleaching of 11% at 0.5% w/v pulp density of ESM. Gold bioleaching was further enhanced to 30% when the pH of the spent medium was increased to shift the equilibrium in favor of cyanide ions production. Spent medium bioleaching of pretreated ESM yield a higher gold recovery compared to two-step bioleaching at a pulp density of 0.5% w/v.

The mining districts located in the western mountain range in the south of Ecuador have gold minerals with refractory characteristics, which do not allow gold recovery by traditional methods used in Ecuador. Therefore, it is necessary to apply some technology that permits to obtain greater metal recovery. Bio-oxidation, as treatment of refractory ores that contain low grade of gold, offers an economic and sustainable alternative for this purpose. The objective of this research was to evaluate the effect of particle size, pulp density and concentration of inoculum and inducer (Fe+2) on the bio-oxidation of refractory gold minerals in order to maximize gold recovery of the bioleached minerals by means of a cyanidation process. The microbial consortium used in this work was collected and isolated from the Portovelo mining district corresponding mostly toAcidithiobacillus ferrooxidansandLeptospirillum ferrooxidansspecies. The Eh, final concentration of ferric ion, total iron and sulfates were measured. Finally, the bio-oxidized material was tested using cyanidation to determine the gold recovery. The results after the cyanidation tests showed that the highest gold recovery was obtained when the bio-oxidation step was conducted with 68-91 µm particle size, 15% pulp density, 20% v/v inoculum and 2 g/L of Fe2+as inducer. At those conditions, gold recovery was 68% compared to 26% obtained when no bio-oxidation step was performed, demonstrating that this process was favorable compared with traditional gold recovery processes

The material treated in the industrial heap bioleaching plant at Escondida Mine includes sulfide, oxide and mixtures of run of mine ore (ROM) with 5% of total copper average grade. The design of the heap considers seven lifts of eighteen meters height each. Nowadays, the heap is being operated with ore loaded in the second and third lifts. The amount of acid required for the process can be increased by increasing the height of the heap and also by the characteristics of the ore. This effect can be attributed to the increase of contact time between ore and solution. The goal of this work was to assess the effect of using raffinate solution with elevated concentration of acid on a microbial culture obtained from process solutions. Reactor tests of culture grown in industrial raffinate solution were performed and DNA and RNA were extracted for qPCR and RT-qPCR analyses, respectively. A design of experiment (DOE) was considered to determine the number of replicates in order to assess the effect of two concentrations of sulfate (80 and 100 g/L) and two incubation temperatures (30 and 45 °C). In addition, analysis of the Most Probable Number (MPN) of iron and sulfur oxidizing organisms and oxidation tests were used to determine the microbial activity in the tests. The results obtained from the DOE showed that acid, temperature and the interaction of temperature and energy source had a significant effect on the microbial activity. Both iron and sulfur oxidizing activities decreased when acid was added at elevated concentration. By other hand, molecular analyses showed differences in levels of specific concentrations of microorganisms and the expression of 16S rRNA gene of the different species thriving in the culture tests.

Mining operations today face a difficult challenge in terms of water availability, with most of these deposits located in arid areas where fresh water is scarce. This is especially relevant for bio-mining operations where not only the source but the water quality can be a decisive factor for its successful utilization. This research evaluates the metallurgical and microbiological performance of an adapted chloride and copper-resistant mixed culture during the leaching (laboratory scale columns) of a secondary copper sulfide at different chloride concentrations. Up to 6 g/l chloride all columns established Eh potentials over 750 mV with complete oxidation of ferrous iron in the PLS showing well established microbial activity. Copper recovery in solution, along with a high redox potential, was established faster in the mesophilic column but leveled off quickly over time. Copper extraction showed that the 6 g/l chloride column has the highest metallurgical performance (83% CuT) with 4 extra points of copper recovery over the 1.5 g/L and 3 g/l Cl- columns. These results are a good indication that comparable copper recovery rates –to the ones achieved using fresh water- can be reached in the presence of important chloride concentrations by way of using the use of a suitable and well adapted microbial population. The related process and chloride-resistant culture have been patented under the following ID N°: EP2313534/US0201095.

More than 90% of metal sulfides in vanadium-bearing titanomagnetite concentrates in Panzhihua (China) are pyrrhotite. It is difficult to remove pyrrhotite from iron ores through conventional mineral processing technologies as magnetic separation and flotation. Desulfurization with the help of microorganisms is a promising alternative way relating to the implementation in dissolution. The effects of pH buffers on growth of Acidithiobacillusthiooxidans and biodesulfurization efficiency of vanadium-bearing titanomagnetite concentrates were investigated. 61.86% of sulfur can be removed from the concentrates after bioleaching for 15 days for a 10% pulp density. While 10% of citric-disodium hydrogen phosphate buffer was added into the solution, Acidithiobacillusthiooxidans grew significantly faster and the biodesulfurization rate was increased by 12.34%, accompanying with pH stabilised at ~ 3.0. Boruitan-Luobisen buffer was helpful to keep pH in a good situation, whereas it inhibited the growth of Acidithiobacillusthiooxidans seriously and brought down the biodesulfurization efficiency.

Bioleaching of the copper flue dust emanating from smelters at Sarcheshmeh Copper Complex has been studied. At the present, the dust is sent back to the smelter, which reduces its efficiency. In this study, a continuous system including a feed tank and two-stage aerated stirred tank bioreactors was established. Mixed mesophile bacteria with different amounts of the dust containing 35% of copper mainly in the form of sulfide minerals were used. The effects of pulp densities, residence times and temperatures on the final copper recovery and redox potential were experienced. Despite the copper concentrates bioleaching, the process of dust bio-treating was net acid consuming. Lower pulp densities resulted in a stable redox potential in both reactors. However, increasing the pulp density to 7%, was created an unstable redox potential in the first bioreactor especially at lower temperatures. Final copper recoveries were calculated for pulp densities of 2%, 4% and 7%, were 91.8%, 90.3% and 87.6% with residence times of 2.7, 4 and 6 days respectively. The promising results indicated that bioleaching is a feasible process that can be applied to copper flue dusts.

The viscosity of Pulp will affect the grinding rate directly, Elevated temperature, the slurry viscosity reduced. In order to study the effect on the grinding rate of temperature, we did the experiment by only changing the temperature, and three groups of contrast test was carried out. The results show that the grinding rate is improved obviously, when the grinding temperature increases from 16 °C to 42 °C.

It is determined through analysing the feature of tailings of Hebei iron stone, which contains TiO2 7.18%, adopting“high intensity magnetic separation-shaking table concentration. The results show that the concentrate with a TiO2 grade of 27.31%, recovery87.75% and productivity 23.07% and the tailing with a TiO2 grade of 1.14%, recovery12.25% and productivity 76.93%.

Bagasse, a fibrous residue from sugarcane juice extraction, was used as a reducing agent to roast low-grade pyrolusite in N2. The roasted ore was further leached using sulfuric acid, to convert manganese oxide in the ore to manganese sulfate. The effects of weight ratio of bagasse to manganese ore, roasting temperature, roasting time, leaching temperature, leaching time, stirring speed and sulfuric acid concentration on the leaching recovery of manganese were investigated. Optimal conditions were determined to be a bagasse to manganese ore weight ratio of 0.8:10, roasting temperature of 500°C for 40 min, leaching stirring speed of 100 rpm, sulfuric acid concentration of 3 mol•L-1 and leaching temperature of 50°C for 40 min. The leaching recovery rate of manganese was up to 97.8% at the optimal conditions.

Titanium oxide is believed as one of the key factors that influence the excellent corrosion properties as well as biocompatibility of titanium alloy. In the present research, thermal-electrochemical anodizing processes were performed in order to form thick layer of titanium oxide on titanium alloys (Ti6Al4V) surface. Oxidation temperature, blasting and anodizing voltage were selected as the evaluated parameters process at the present study. It was observed that temperature plays important role in the formation of oxide layer, where the thickness of the oxide increases significantly as temperature increases. However, for the case of oxide layer formed by thermal oxidation at temperature of 950oC, oxide layer on the non-blasted sample become easily peel off, whereas oxide layer on the blasted sample shows good adhesion properties. In addition, oxide layer on the blasted samples also have thicker layer as compared with oxide on the non-blasted sample. On the other hand, it was observed that further oxidation by anodizing at 43V and 63V create finer oxide layer by the filled up of porosity on the existing oxide layer. However decreasing of oxide layer thickness was also observed after anodizing, which is predicted due to the breaking up the outer oxide layer during anodizing process.

For the Mo-Ni ore that mineral composition is complex, and the grade is relatively low, the flotation’s effect is not good in advance for enrichment, because of the influence of fine grained level gangue minerals. The small diameter hydrocyclone were used to pre-discard tailings, with the best pulp density and feed pressure, the rate of throwing is the 30%, and then the flotation obtained a good beneficiation index. The crude ore that contains Mo 2.04 %, Ni 1.87 %, through the closed-circuit test won a concentrate that the grade of Mo is 8.94 % and the recovery is 91.86 %, the grade of Ni is 6.75 % and the recovery is 86.79 %. Compared with the single flotation process, it improved the flotation effect and the enrichment ratio of Mo Ni, and realized the efficient enrichment of Mo-Ni.

This study reached a gold ore which contain 3.83g/t gold, to investigate the available gold recover methods, direct cyanide leaching test and “biooxidation-cyanide” leaching process were utilized after enrich gold by flotation. When regrinding the flotation concentrate to 95% -325mm, the leaching rate of “biooxidation-cyanide” leaching reached 94.47%, compare with direct leaching, the leaching rate increased almost 67%. Obviously bacterium oxidation is a useful pretreatment for gold leaching.

In this experiment, the copper-containing wastewater was adsorbed by HAP which was prepared by high temperature calcination after high temperature cooking fish scales. By the single factor experiments and orthogonal experiments, the optimal conditions were as follows: the initial concentration of copper ion was 200mg/L,the dosage of HAP was 0.2g,the reaction time was 30min,and pH was 5. The maximum removal efficiency was 98.23%.

Kaolin is a mineral composition of water cut aluminum silicate collection of words, used widely. But since most kaolin contain quality score 0.5% ~ 3% of iron oxide or hydrogen ferric oxide, restricted its use. With reduction and complexation method to kaolin bleach, which can effectively reduce the content of iron in the clay. The low pH in with organic acid(citric acid, acid, oxalic acid, also sugar) refined bleached high content of coal kaolin ferric oxide. The results show that, citric acid and also the sugar acid in iron effect is poor, does not meet the industrialized production, oxalic acid can remove kaolin can dip in iron, when pH lower than 1.2, the temperature of 80 °C on the bleaching, white degree of more than 80%, to adapt to the industrial application of coal kaolin basic conditions. At the same time, because of the difference of shading minerals, different sources of kaolin bleaching and the white degree stability condition is different, the actual production of should according to the specific of the sources, after the test to be sure.

The flotation performance of a complex lead and zinc ore were investigated by changing the grinding environments. Four groups of testing were conducted with different depressants or their combinations. Flotation results, size-by-size analysis, pulp potential (Eh) and dissolved oxygen (D0) were studied. It was found that the addition of depressants during grinding was beneficial to increasing the separation efficiency.

The study aims to recovery of silver minerals from zinc leach residue by flotation method with mixed collectors, namely, ammonium dibutyl dithiophosphate (ADD) and diethyl dithiocarbamate (DD). The effect of key parameters, i.e., grinding fineness, dosage of collectors and dosage of sodium chloride on the flotation performance was investigated. The results indicate that dosages of ADD and DD have both significant effects on the flotation performance, and sodium chloride plays an important role in the increase of the grade of silver, by eliminating the detrimental effect of Zn2+ in the pulp. The optimum conditions for flotation of silver from the material were identified as grinding fineness of 90%, dosage of ADD at 400 g/t, dosage of DD at 75 g/t and dosage of NaCl at 60 g/t; under such a condition, a sliver recovery of 76.92% with a concentrate grade of 2012.30 g/t was achieved, and the tailing from the flotation has a lower sliver grade of 17.30g/t, with only 15.04% of silver lost in the tailing.

A new technology of pellet production-drying-chloridizing roasting is proposed for comprehensive utilization of sulfuric acid residue with high content of copper, a common by-product in vitriol industry. The sulfuric acid residue, containing 60.27% Fe, and 1.61% Cu, was pelletized with addition of 5% bentonite in pan pelletizer. Green balls after drying with 2.3% of water retention were roasting at 1100 °C for 30 min with 5 wt % of CaCl2addition in tube furnace. The results demonstrate that pellets with 60.58% of TFe, a copper volatite ratio of 97.8% were obtained with simultaneous decrease in the copper content down to 0.035%. Key technique is that CaCl2reacts with copper compounds and the chloride can be volatilized at moderate temperatures. This new technology can be used to fully utilize sulfuric acid residue and produce qualified concentrate as iron-bearing feed for steel industry, which will help to solve the pollution of sulfuric acid residue and extend raw material sourcing for Chinese steel industry.

According to the bentonites properties and mineral composition, three bentonites with 32-36% montmorillonite content(MC) from Laiyang, Shandong, China, are purified for utilizing low grade bentonite sufficiently. Research shows that the purification is effective by separating –325 mesh products from raw bentonite after soaking, stirring and rubbing in water. Firstly, the three bentonites are combined into one and soaked in water for 24h with the ratio of liquid and solid 15:1, and then, the bentonite is purified using –325 mesh sieve after stirring and rubbing in water for 1h with pulp density of 26%. Methylene blue index(MBI) of the product is 22.52g/100g, swell index(SI) is 5.5mL/2g, water absorption(WA) is 184.3%, water content(Wa.C) is 9.7%, and the indexes meet the stantard of three grade Ca-bentonite(TGCB)applying to iron ore pellets.

Chinese fir (Cunninghamia lanceolata Hook.) and Mongolian Scots pine (Pinus sylvestris Linn. var. mongolica Litv.) with dimension of 19.019.0450.0 mm were treated with two concentrations of amine copper quat-type D (ACQ-D) solutions (0.5%, 1.0%) respectively and post-treated with three different methods including humidity chamber, drying oven and hot water bath. The effects of these variables on copper leaching from ACQ-D treated wood were investigated according to the leaching test of AWPA E11. The results showed that post-treatment could improve the leaching resistance of ACQ-D treated wood effectively compared to the specimens those were leached immediately after impregnation. After some promising post-treatments, copper leaching from the treated wood was not only associated with the joint effects of retentions, wood species and different locations in the treated wood, but also influenced by the special fixation mechanisms in different post-treatments.

This work compares gold bioleaching from e-waste containing gold and copper by Chromobacterium violaceum and Pseudomonas fluorescens. The effect of pulp density (ranging from 0.5 to 8%w/v) was examined. Although C. violaceum produced more cyanide than P. fluorescens in the absence of e-waste, P. fluorescens showed higher growth rate, cyanide production and gold leaching efficiency at all pulp densities. Pretreatment with biooxidation of the e-waste using Acidithiobacillus ferrooxidans resulted in the removal in excess of 80% of the copper present in the waste, and increased the gold/copper ratio in the residual solid. Bioleaching the biooxidised e-waste significantly improved gold recovery, especially by C. violaceum, particularly at high pulp density. For example, at pulp densities of 2 and 4% w/v, gold recovery from non-biooxidzed e-waste was 0.22 and 0.14% respectively. Higher gold recovery, at 8%, was obtained for bioleaching of the biooxidised e-waste at both these pulp densities. The ratio of gold/copper in leachates after bioleaching of the biooxidized e-waste was also found to be increased.

Bioleaching of secondary sulfides is a technical and economical well established bioprocess. However in the case of bioleaching of primary sulfides, like chalcopyrite and enargite, still is necessary to improve the bioprocess kinetic. One alternative that has been proposed to overcome this situation is to use hyperthermophilic bioleaching microorganisms. Nevertheless, higher process temperatures modifies in a different extent operation parameters like CO2 and O2 transfer rates, both gases being essential to the bioprocess. The aim of this work was to establish quantitatively, using a continuous bioreactor operating at steady state conditions, which gas limits the growth and activity of bioleaching microorganisms when air is used as source of both of them. The experiments were run in a 3.3 L agitated continuous bioreactor operated at 70°C, pH 1.8 and 150 g/L of copper concentrate rich in chalcopyrite. Operating at steady state condition with an aeration rate of 1.2 vvm, a copper solubilization volumetric productivity of 1.7 g(Cu2+)(L•day)-1 and a copper extraction of 55% were obtained. Enriching the inflow air with CO2 up to 5% (v/v) showed the maximum values of these indexes, increasing 34% the volumetric productivity of copper solubilization and reaching 74% of copper extraction. On the opposite way, enriching air with oxygen or increasing the aeration rate did not bring about any change either of the volumetric productivity or the percentage of copper extraction. The results allow concluding that the CO2 is the limiting nutrient for cell growth in the continuous bioleaching of a chalcopyrite concentrate using hyperthermophilic microorganisms.

Talvivaara complex multi-metal black schist deposit in Sotkamo, Finland, is the largest known sulfide nickel deposit in Europe with 340 million ton of classified resources. The mine can be operated for a minimum of 25 years with an annual nickel output of over 30 000 ton, which is about 2,5 % of the global production of primary nickel. Significant amounts of zinc, copper and cobalt can also be produced. In summer 2005, a 50 000 ton demonstration plant was constructed to the mine site. A representative ore sample was mined, crushed to 80 % -8 mm, agglomerated and built to a two-part heap (8 m high, 50m times 80 m). Irrigation of the heap was started in August 2005. The pilot heap was inoculated with indigenous bacteria collected from the site. The amount of bacteria in the pregnant leaching solution has been in the range of 106 – 108 cells/ml. The bacteria involved are mesophilic and thermophilic ones. The start-up of the solution flow resulted soon in elevated temperatures of over 50 0C in the pregnant leaching solution. The rise is due to the oxidation of the large quantity of pyrrhotite and pyrite in the ore. The elevated temperatures have also been maintained over the boreal winter conditions. Metal recovery was started in November 2005. At the end of the year 2006 94 % of Ni, 83 % of Zn, 3 % of Cu and 14 % of Co have been recovered. The demonstration plant is still running. The study has proven that Talvivaara black schist ore is well suited for bioheapleaching. Building of the mine will start in spring 2007, bioheapleaching in summer 2008 and the metal recovery plant in autumn 2008, if everything proceeds according to the plans.

In the frame of a European project (BioMinE - FP6), a continuous bioleaching operation was carried out in a laboratory-scale unit using a cobaltiferous pyrite. The objective of the work was to use this system to investigate mechanisms of microbial activity and mineral oxidation in continuous stirred bioreactors (1x50L - 3x20L). A combination of scientific and technical approaches (molecular ecology, biochemistry and microscopy) was used and various key operating parameters were tested (temperature, nitrogen source, CO2 availability, designed consortia). An increase of temperature of 10°C (35°C to 45°C) had no major influence on the bioleaching efficiency. When the ammonium source was limiting, there was a negative influence on both bacterial growth and bioleaching efficiency. This result was related to a combination of factors such as less bacterial attachment to the pyrite surface and less precipitate formation. CO2 limitation had a very significant negative effect on the bacterial productivity and consequently on the bioleaching efficiency. Nevertheless, the population composition remained unchanged. An important decrease of EPS (sugar) production was also observed. The bacterial strains, that dominate the culture, originated from the deposit in Uganda. It seems that their bioleaching ability was improved over the time when cultured in continuous mode. The culture composition was very stable. The iron-oxidizer L. ferriphilum was the dominant organism in standard (not limiting) conditions, and was always very well represented during the first 3-4 days of residence time. Sulfobacillus sp. BRGM2 also played an important role in the process. This study gives new insights for the application of this technology, and more specifically on the influence of key operating parameters on bioleaching performances, population dynamics and attachment of bacteria to the solid surfaces.

Identifying influential factors in the bacterial leaching of nickel laterites using a mixed culture of chemolithotrophic micro-organisms was explored using the approach of statistical design of experiments. In a series of experiments, pH, particle size, pulp density, type of substrate and inoculum size were statistically combined using a quarter fractional factorial designs 2 5−2 III and tested for their influence on nickel recovery using chemolithotrophic microorganisms. The results indicated that inoculum size was not statistically significant while the rest of the factors were statistically significant. Under the ranges studied the interaction between the variables was found to be weak. The results also showed that recovery was maximized at low pH and low pulp density. In the range studied, particles of less than 38μm had a negative influence on nickel recovery. Sulphur substrate also showed better effects than pyrite.

In this work, bioleaching of iron from a kaolin sample was carried out using two different strains of Aspergillus niger, and the effects of strain type, pulp density, and addition time of clay on the iron removal were investigated using a full factorial design. It is concluded that strain type has the most significant effect on the iron removal. Also, the highest removal extent was 42.8% that was achieved by using the strain isolated from pistachio shell at the pulp density of 20 g/l, when the clay was added at the beginning of the experiments. The results showed that for the experiments in which the clay was added in the first day of cultivation, the average organic acids concentration (citric acid: 5.6 g/l, and oxalic acid: 4.54 g/l) were higher in comparison to those experiments in which the clay was added in the third day (citric acid: 5.25 g/l, and oxalic acid: 2.87).

The problem of steel products corrosion is increasingly outstanding, which causes a serious waste of resources. This thesis focuses on the study of a new formula for rust removing, adding some additives such as, corrosion inhibitor, complex agent, surfactant into the acid liquor, which is able to remove the rust layer effectively and protect metal products, economic and applicable. Through many testing on different ratio of additives composition, we obtain the optimal formula.

The paper present some general aspects regarding results obtained by ISIM Timișoara at FSW of steel alloys, with wide use in important industrial fields. The paper also contains information on own contributions of ISIM Timișoara in the field of FSW.Until the present, ISIM Timisoara has responded to some specific requests from the industry, for applying of the FSW process to light alloys and industrial copper Cu 99.The paper presents some general elements regarding the results obtained to welding steels having wide use in industry and which can substantiate industrial applications.The experimental welding programs were developed using the techniques of application of the FSW process, made by ISIM Timisoara: FSW welding machine, welding tools for steels, monitoring systems of the welding process FSW, respectively system for applying of the FSW-TIG hybrid welding process.Sintered tungsten carbide P20S tools with smooth shoulder and pine in 3 constructive variants: smooth conical, smooth cylindrical and pine with four flat recesses (pyramid trunk) were used.It has been shown that the welding tools made of P20S tungsten carbide, with sharp edges, are more resistant and present the best solution for FSW applications.Experimental programs have shown that by observing specific process conditions, the FSW process can be applied with excellent results when welding steel.