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In order to enable encryption algorithm to be higher security and better computational efficiency, a new way to produce key stream based on Logistic mapping is proposed. As a result, the key produc...

An efficient sintering process was proposed based on the autocatalytic denitrification of the sintered ore. The catalytic denitrification of sintered ore, the effect of double-layer ignition sintering process on the emission reduction in nitrogen oxides, and the impact on the quality of sintered ore were studied. The results showed that the catalyzed reduction of NO with sinter ore as a catalyst has a significant effect; when the airspeed reaches 3000 h−1, the temperature is 500 °C, and the conversion rate of NO can reach 99.58%. The sinter yield of double-layer ignition sintering is increased, solid fuel consumption is slightly reduced, falling strength is slightly increased, and drum strength is slightly decreased. Under the conditions of layer height proportion of 320/400 mm (lower/upper) and ignition time interval of 10 min, the yield, drum strength, shatter strength, and solid fuel consumption reached 61.60%, 54.82%, 46.75%, and 69.55%, respectively. NOx concentration under the 16% baseline oxygen content (c(NOx)’) in the flue gas of double-layer ignition sintering is reduced to a certain extent, and the generation time of NOx is greatly shortened. The double-layer ignition sintering process can reduce the emission of nitrogen oxides in the sintering process under the condition of guaranteeing the quality of sinter, which has great economic and environmental benefits.

In big data era, people cannot afford more and more complex computation work due to the constrained computation resources. The high reliability, strong processing capacity, large storage space of c...

In attribute-based encryption schemes, an honest authority are always used to distribute members’ private keys. But in reality applications, the authority is general dishonest. The authority can decrypt the encrypted message by using some member’s private key. So we should handle with authority. In this paper, a security ABE scheme is proposed to prevent the authority to abuse the members’ private keys. The proposed scheme relies on the interpolating polynomial. We prove that our scheme is secure for the protection of members’ private keys and can tolerate a curious, semi-honest and non-colluding authority.

The research of smelting low ferronickel from pre-concentrate nickel-iron ore with 2.76 % Ni and 38.00 % Fetotal was carried out to find an effective way for stainless steel enterprises to use the low-nickel laterite reasonable. The results show that Ni and Fe both have a certain degree of enrichment, and impurities and harm elements have different degrees of reduction after pre-concentration of nickel-iron ore. Most valuable metal did not compound with impurities which greatly accelerated the speed and extent of melt separation reduction. Good alloy of 6.58 % Ni with the overall recoveries of 93.38 % and 89.95 % Fetotal with the overall recoveries of 89.57 % was manufactured under the following conditions: 10 % coke, 1.0 binary basicity, 18 % MgO and 3 % Al2O3 in slag, melting at 1,550 °C for 10 min. The product can be used for the feed of producing stainless steel.

The granulation behaviour of specularite fines which possess poor ballability was studied with limonite fines as a function of nuclei particles and adhering fines. The results show that the permeability of granules deteriorated as the ratio of specularite fines increased in the mixture, and the optimal granulation moisture content also decreased. The granulation kinetics results demonstrate that the adhering load of specularite fines increased rapidly within 3 minutes and then levelled off. With increasing specularite fines ratio, the adhering rate accelerated but the granulation duration needed to be longer to reach adhering balance. The microstructure of granule quasi-particles indicates that the fine limonite particles act as binders to bond together the specularite particles which are dispersed in the adhering layers. This can improve the adhering strength of the granules. Hence, the granulation behaviour of specularite fines can be improved by blending them with fine limonite ores which have high adh...

Solid wastes derived from metallurgical industries have created threats to the environment and their disposal is a major concern for the World. Semi-coke generated in the coal-based direct reduction process of iron ore is a solid waste and its effective utilisation has not been developed so far. In order to develop it properly, the characteristics of this semi-coke have been comprehensively studied and an investigation was carried out into the use of semi-coke as an alternative fuel in iron ore sintering. It is shown that the semi-coke could be substituted for coke breeze without affecting the sintering and metallurgical performances by adjusting its size distribution to offset the adverse effect of its superior combustion properties. In addition, the application of semi-coke in sintering could decrease SOx and NOx pollutants by 66 and 25%, respectively, in waste gas compared with coke breeze as solid fuel.

How to utilize low grade complex iron resources is an issue that has attracted much attention due to the continuous and huge consumption of iron ores in China. High-aluminum iron ore is a refractory resource and is difficult to upgrade by separating iron and alumina. An innovative technology involving synergistic reducing and synergistic smelting a high-aluminum iron ore containing 41.92% Fetotal, 13.74% Al2O3, and 13.96% SiO2 with a high-manganese iron ore assaying 9.24% Mntotal is proposed. The synergistic reduction process is presented and its enhancing mechanism is discussed. The results show that the generation of hercynite (FeAl2O4) and fayalite (Fe2SiO4) leads to a low metallization degree of 66.49% of the high-aluminum iron ore. Over 90% of the metallization degree is obtained by synergistic reducing with 60% of the high-manganese iron ore. The mechanism of synergistic reduction can be described as follows: MnO from the high-manganese ore chemically combines with Fe2SiO4 and FeAl2O4 to generate Mn2SiO4, MnAl2O4 and FeO, resulting in higher activity of FeO, which can be reduced to Fe in a CO atmosphere. The main products of the synergistic reduction process consist of Fe, Mn2SiO4, and MnAl2O4.

In order to provide a better theoretical foundation for utilisation of Xinjiang siderite resources in China, its thermal decomposition behaviour was studied in neutral and oxidising atmospheres by employing thermodynamics analysis, chemical titration, thermogravimetric, and X-ray diffraction means. Isothermal experiments were conducted to investigate the thermal decomposition kinetics of siderite lump in a weakly oxidising atmosphere at 500–850°C. The results reveal that siderite has self-magnetisation characteristics under controlled conditions, and the phase evolution process and final products of decomposition depend temperature and atmosphere. The phase transformation process in weak oxidising atmosphere follows the steps as: FeCO3 → Fe3O4 → γ-Fe2O3 at 550°C, and FeCO3 → FeO + Fe3O4 → Fe3O4 → γ-Fe2O3 → α-Fe2O3 at 800°C. In inert atmosphere, the decomposition pathway is FeCO3 → Fe3O4 below 733°C and FeCO3 → FeO + Fe3O4 above 733°C. The molar ratio of FeO/Fe3O4 increases with temperature. The decomposit...

Solid wastes derived from metallurgical industries pose a significant threat to environment. The utilization and disposal of these solid wastes are the major concern in the world. Semi-coke generated in coal-based direct reduction process of iron ore is a by-product and its suitable utilization is not available so far. In order to handle it properly, the characteristics of this by-product were comprehensively investigated. A series of analysis methods were used to demonstrate its mineral compositions, petrography and physico-chemical properties. The results reveal that the semi-coke has poor washability. The fixed carbon content of semi-coke reaches 76.11% and the gross calorific value is 28.10 MJ/kg, both of which are similar to those of traditional sinter coke breeze. Also, semi-coke ash possesses lower content of SiO2, Al2O3, S and higher content of CaO and MgO, which could improve the strength of sinter ore when partially substituting for coke breeze in sintering. Semi-coke features well-development porous structure and higher reaction activity, which predicts that the sintering speed could be elevated to some extent when employing it as a partial replacement of coke breeze, so the studies further suggest that the potential adverse effect of the high reactivity on sintering process could be weakened by adequately coarsening the semi-coke’s particle size.

Pelletization is one of useful processes for the agglomeration of iron ore or concentrates. However, manganese ore fines are mainly agglomerated by sintering due to its high combined water which adversely affects the roasting performance of pellets. In this work, high pressure roll grinding (HPRG) process and optimization of temperature elevation system were investigated to improve the strength of fired manganese ore pellets. It is shown that the manganese ore possesses good ballability after being pretreated by HPRG twice, and good green balls were produced under the conditions of blending 2.0% bentonite in the feed, balling for 7 min at 16.00% moisture. High quality roasted pellets with the compressive strength of 2711 N per pellet were manufactured through preheating at 1050 °C for 10 min and firing at 1335 °C for 15 min by controlling the cracks formation. The fired manganese pellets keep the strength by the solid interconnection of recrystallized pyrolusite grains and the binding of manganite liquid phase which filled the pores and clearance among minerals. The product pellets contain high Mn grade and low impurities, and can be used to smelt ferromanganese, which provides a possible way to use imported manganese ore fines containing high combined water to produce high value ferromanganese.

In order to utilize slag discarded by nickel plants, the selective recovery of nickel and copper versus iron was investigated by selective reduction, which was achieved by controlling the reduction parameters and magnetic separation process on bench scale. The results show that increasing the basicity (mass ratio of CaO to SiO2) of nickel slag facilitates the enrichment of nickel and copper. The process parameters for selective reduction were optimized as follows: basicity of 0.15, reducing at 1200 °C for 20 min, 5% coal on a dried slag mass base. The grinding-magnetic separation results of reduced briquettes show that concentrate containing 3.25%Ni, 1.20%Cu and 75.26%Fe is obtained and selective enrichment is achieved with a recovery of 82.20%, 80.00% for nickel and copper respectively, while the recovery of iron is only 42.17%. The S and P contents are not reduced obviously and further research may be needed to examine the behaviors of S and P in the process.

In the era of information explosion, people have to deal with huge amount of data. It is a great computation burden for the resource- constrained clients. Cloud computing connects large amounts of network resources, and forms a vast pool of resources. It provides much con- venience for people. Clients can outsource the complex computation task to the powerful cloud server. In this way, the computation burden of clients can be greatly reduced. In this paper a new algorithm of secure outsourcing for polyno- mials is proposed. In the computation process, the computation polynomial is hidden to cloud server, and the inputs and outputs of polynomi- als will not revealed. In addition, clients can ver- ify the result easily.

In this paper, a study of processing pyrite cinder and metallurgical slag using a ‘one step’ technology in strand grate–rotary kiln at a laboratory scale is presented, which aims to recover iron, lead, zinc and copper. The compressive strength of preheated pellets reached 527 N per pellet and the removal rates of copper, lead and zinc reached 36·36, 92·86 and 20·0% respectively, when the green balls were preheated at 1125°C for 10 min. Reduction of preheated pellets was followed, at the carbon/iron ratio of 3·0 and 1100°C, for the reduction time of 70 min, and the metallisation degree of 86·31%, the compressive strength of 1777 N per pellet and the copper, lead and zinc removal rates of 36·36, 99·12 and 71·00% were achieved respectively. These prereduced pellets with 80·58%Fe made from pyrite cinder and metallurgical slag can be widely applied to enhance the operation of blast furnace.

The wood-concrete composite beams consist of the wooden beams and concrete slabs by using shear connectors together into a whole load.With the development of society and economy as well as the accumulation of experience in scientific research,people have a further understanding and mastering about the structure performance and application of wood-concrete composite beams.This paper will detailedly introduce the research status concerning wood-concrete composite beams at home and abroad, and discuss the application and development of that composite structure.

Groundwaters and surface water in the Shihongtan sandstone-hosted U ore district, Xinjiang, NW China, were sampled and analyzed for their major-, and trace element concentrations and oxygen, hydrogen, boron and strontium isotope compositions in order to assess the possible origins of the waters and water–rock interactions that occurred in the deep aquifer system. The waters in the study district have been grouped into three hydrochemical facies: Facies 1, potable spring-water, is a pH neutral (7.0), Na–Ca–HCO3 type water with low total dissolved solids (TDS; 0.2 g/l, fresh) and has δ18O of − 8.3‰, δD of − 48.2‰,δ11B of 1.5‰, and 87Sr/86Sr of 0.70627. Facies 2 groundwaters are mildly acidic to mildly alkaline (pH of 6.5–8.0, mean 7.3), Na–Ca–Mg–Cl–SO4 type waters with moderate TDS (8.2 g/l–17.2 g/l, mean 9.3 g/l, brackish) and haveδ18O values in the − 5.8‰ to − 9.3‰ range (mean − 8.1‰), δD values in the − 20.8‰ to − 85.5‰ range (mean − 47.0‰),δ11B values in the + 9.5‰ to + 39.1‰ range (mean + 17.1‰), and 87Sr/86Sr values in the 0.70595 to 0.70975 range (mean 0.70826). Facies 3, Aiting Lake water, is a mildly alkaline (pH = 7.4), Na–Ca–Mg–Cl–SO4 type water with the highest TDS (249.1 g/l, brine) and has δ18O of − 2.8‰, δD of − 45.8‰,δ11B of 21.2‰, and 87Sr/86Sr of 0.70840. The waters from the study district show a systematic increase in major, trace element and TDS concentrations and δ11B values along the pathway of groundwater migration which can only be interpreted in terms of water–rock interaction at depth and strong surface evaporation. The hydrochemical and isotopic data presented here confirm that the groundwaters in the Shihongtan ore district are the combined result of migration, water–rock interaction and mixing of meteoric water with connate waters contained in sediments.

The problem of data security is one of the main problems plaguing the development of cloud computing, in view of the current cloud computing user data safety storage applications demand increase, need to greatly improve the data read-write efficiency problems, put forward the use of symmetric encryption and asymmetric encryption algorithm combining encryption, decryption scheme, suitable for large-scale data using a symmetric key encryption the symmetric key is itself, rather than the characteristics of high safety, give full play to the advantages of both computing environment in the clouds, to achieve a safe storage and good reading and writing data storage strategy to achieve high efficiency; the premise of asymmetric key encryption system in data security, the efficiency of the algorithm is close to the encryption system the symmetric key levels.

The grate-kiln process has been widely applied for oxide pellet production with the quick development of steel industry in China, but ring formation takes place which adversely affects the productivity and properties of fired pellets. Rotary kiln at high temperature seems a black box, and ring formation is difficult to measure directly by current technology. It’s of great importance to monitor ring formation during firing of pellets. Therefore, a method for estimating the thickness of ring formation in rotary kilns was studied, based on working out theoretically the relationship between ring thickness and the outside surface of the kiln, according to steady-state heat transfer across a cylinder, which provides a soft-sensing technique for ring formation at high temperature, and achieves stable pellet production.