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The dissolution behaviors of various minerals in the tellurium–bismuth ore during oxidic–acidic leaching were investigated systematically in this work. The Te–Bi phase in the ore distributes in network shape, triangular shape, tree shape, strip shape, bulk shape, sparse granule, flake shape, crescent, etc., which are closely intercalated with FeS, FeS2, and CaCO3·(Mg,Fe,Mn)CO3. Under suitable conditions, 95.61% Te and 95.77% Bi can be recovered. Within 20 min of the initial leaching, most of dolomite and Te–Bi phase dissolve rapidly. With the extension of leaching time, a large amount of rod-shape CaSO4 particles form, attach on the surface of the tellurium–bismuth ore particles, and then grow and coarsen. The (Mg,Fe,Al)(Si,Al)Ox(OH)y phase dissolves mainly within 60 min. Fe–S phase can be corroded but cannot dissolve completely. SiO2 cannot dissolve at all. Besides, H2SO4 and Fe3+ play a significant role on the dissolution of various minerals in the ore. Without Fe3+ or H2SO4 in immersion liquid, Te and Bi are difficult to be leached into the lixivium from the tellurium–bismuth ore. As H2SO4 concentration and Fe3+ concentration increase, Te–Bi phase and Fe–Mg–Al–Si–O phase gradually dissolve, the Fe–S phase can be corroded obviously but cannot dissolve, and the Si–O phase has no change. The dissolution of dolomite is mainly controlled by H2SO4. The dissolution behaviors of various minerals in the tellurium–bismuth ore during oxidic–acidic leaching were investigated systematically. Most of dolomite and Te–Bi phase dissolve rapidly. A large amount of rod-shape CaSO4 particles form, attach on the surface of the tellurium–bismuth ore particles, and then grow and coarsen. H2SO4 and Fe3+ play a significant role on the dissolution of various minerals in the ore.

Based on two considerations of making full use of the residual heat of vanadium slag and exploring a novel green vanadium extraction process, this article employs vanadium slag with high MgO content as raw material, blowing oxygen into the molten vanadium slag and using the residual heat of the vanadium slag to carry out high-temperature roasting experiments. XRD and SEM/EDS were used to characterize the phase evolution and morphology of vanadium slag with high MgO content during oxidation. The results show that at a high temperature of 1723 K, the trivalent vanadium in vanadium slag can be partly transformed into acid-soluble pentavalent vanadium. Titanium-bearing spinel was oxidized into a large amount of strip pseudobrookite Fe2TiO5. After oxidation, vanadium existed in the form of the solid solution of magnesium pyrovanadate (Mg, Mn, Ca)2V2O7. The leaching rate of roasted vanadium slag with high MgO content is significantly higher than that of industrial vanadium slag. With the increase of oxygen blowing time from 10 to 30 minutes, the leaching rate of roasted vanadium slag with high MgO content increases from 23.19 to 53.69 pct.

This article investigated the saturated solubility of MgO in converter vanadium slag and its influencing factors. The experimental results of MgO dissolution equilibrium are consistent with the theoretical calculation results. The results show that in MgO saturated vanadium slag, MgO mainly exists in MgV2O4 and MgSiO3. The increase of V2O3 content or the decrease of the FeO/SiO2 ratio is beneficial to increasing the saturated solubility of MgO in the FeO-SiO2-V2O3 slag system. The saturated solubility of MgO in vanadium slag increases from 7.5 to 8.0 wt.% when the temperature increases from 1633 to 1753 K. In addition, the solubility of MgO also increases with the increase of TiO2 and Al2O3 content and decreases with the increase of MnO content.

Aiming at the high-efficiency utilization of vanadium–titanium magnetite with high chromium content, a slag formation path in the converter smelting process of semi-steel containing chromium was pr...

Objective To investigate the prevalence, harm and risk factors of hyperuricemia (HUA) among middle-aged and elderly residents in Tianning District of Changzhou City, Jiangsu Province. Methods From January to May 2018, a total of 6110 residents aged over fifty years were randomly selected from two communities in Tianning District of Changzhou City, Jiangsu Province, and then arranged to take part in a questionnaire and physical examination. Their fasting venous blood were extracted for detection of serum uric acid, creatinine, urea nitrogen, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG). The prevalence of HUA in all the subjects and the clinical features of HUA patients were investigated, the factors affecting HUA were analyzed with monofactorial independent-samples t test and multivariate logistic regression analysis, and the relationship of bad habits and comorbidities to HUA was analyzed with monofactorial independent-samples t test. Results Rejecting the subjects with incomplete data, 5848 subjects were involved in present investigation, among them 993 were HUA patients (17.0%). Compared with those with normal uric acid, the proportion of males [50.5%(501/993) vs. 45.4%(2206/4855), P=0.004] was higher, the average age [(67.9±9.4) vs. (66.6±8.7), P

This paper investigated the non-isothermal crystallization kinetics of the spinel crystals in vanadium slags containing high CaO content. Experiments were performed in combination with theoretical calculation to address this issue, and statistical analyses based on the Crystal Size Distribution theory. The results indicate that low cooling rate and high CaO content benefit the growth of spinel crystals. The growth mechanism is revealed to be controlled by interface reactions and diffusion at the cooling rates of 5 K/min and 15 K/min, respectively. However, at higher temperatures (>1673 K), the growth of spinel crystals is controlled by nucleation. While the temperature is decreased to 1523 K at the cooling rate of 5 K/min, the mean diameter of spinel crystals could reach 36.44 μm. Experimental results combining with theoretical reveal that low cooling rate benefits spinels growth, especially for the interval of 1523 K–1200 K.

The coupled systems of fatigue crack initiation problem undergoing large range damage is defined. The zero different work principle, coupled potential energy principle, coupled complementary energy principle in the coupled system is established. By using of coupled potential energy principle, Closed form solution about predicting fatigue crack initiation life of three-dimensional component which leads to large range damage is derived. Compared with reference [1], the close form solution derived from this some. It is proved that the method is correct. The method adopted in this paper is definite in mechanical concept,it can be widely used in analysis of predicting fatigue crack initiation life of various component which leads to large range damage.

An effective way to decrease the dephosphorization burden in the current vanadium extraction-steelmaking process is slagging with CaO in vanadium extraction step. The phase composition of vanadium slag with different basicity and the regularities distribution of elements have been investigated by X-ray diffraction analysis and scanning electron microscopy combining with energy disperse X-ray spectrometry, respectively. The results indicate that V mainly concentrates in the spinel phases; Ca and P are rich in the silicate phases. Fe2SiO4 transform to CaFeSiO4, while the basicity of vanadium slag is 1.3. With further increase of basicity, 2CaO·SiO2 could form in the silicate phases. Moreover, the phosphorus-containing phase will transform from Ca3(PO4)2 to Ca3(PO4)2-nCa2SiO4. With the increase of P2O5 content, the crystallization rate of spinels decrease obviously. Furthermore, the peak temperature for crystallization of spinels decrease 5 K with the P2O5 content increasing 1 wt%.

In order to recover the chromium resource in chromium-containing vanadium extraction residue , a promising method is to prepare ferrochromium with the residue. The synthetic residue has been reduced under 1300, 1350 and 1400 °C at the reduction time of 1, 2 and 3 h respectively. The reduced samples have been smelted and separated by an induction furnace. The contents of chromium and iron in metallic phase have been determined by an inductively-coupled plasma spectrometer. The results indicate that chromium iron carbide (Cr, Fe)3C7 is the intermediate phase and titanium oxides have been reduced during the reduction process. While the sample has been reduced under 1400 °C for 3 h, metallic phase becomes the dominate phase and reduction reactions almost complete. Moreover, the chromium content in the metal phase reaches 10.19%.

Applied damage mechanics and coupled finite element method, to study the fatigue crack initiation life problem. Application of coupling finite element method, the damage coupling effect can be modified through the global stiffness matrix to achieve. The step length of the damage evolution is divided by the damage variable of the critical element, and then the damage evolution is analysised. The corresponding stiffness matrix and loading matrix can be obtained continually under the condition of increasing the damage evolution step of the critical element,then the equivalent stress can be calculated. The corresponding fatigue crack initiation life can be calculated by using the damage evolution equation, the progress will not stop until the damage degree of the critical element reaches to one. The fatigue crack initiation life is obtained by adding the fatigue crack initiation lives with different damage variable.

Using coupied variational principle, predicting fatigue crack initiation life of plane stress state plate-like component which leads to large range damage is analysed. The closed form solution about predicting fatigue crack initiation life of plane stress state plate-like component which leads to large range damage is derived. The method adopted in this paper is definite in mechanical concept，it can be widely used in analysis of predicting fatigue crack initiation life of various plate-like component which leads to large range damage. A new thinking and new method is provided for predicting crack initiation life of plate-like component.

As one of the manganese oxides, which are easily generated and widely distributed in supergene environment, manganite participates in the oxidation of dissolvable sulfide (S²⁻), and affects the migration, transformation, and the fate of sulfides. In the present work, the redox mechanism was studied by determining the intermediates, and the influence of initial pH and oxygen atmosphere on the processes were studied. The chemical composition, crystal structures and micromorphologies were characterized by XRD, FTIR and TEM. The concentration of S²⁻ and its oxidation products were analyzed using spectrophotometer, high performance liquid chromatograph and ion chromatograph. The results indicated that elemental sulfur was formed as the major oxidation product of S²⁻ oxidation, and decreased pH could accelerate the oxidation rate of S²⁻ in the initial stage, however, there was no significant influence on final products. Elemental S could be further oxidized to S₂O₃²⁻ when the reaction system was bubbled with oxygen, and manganite exhibited excellent catalytic performance and chemical stability during the oxidation of dissolvable sulfide by oxygen. After reaction of more than 10 h, the crystal structure of manganite remained stable.

Adding CaO into the vanadium extraction converter is an effective way to decrease the dephosphorization burden in subsequent steelmaking process. The crystallisation process of spinel is one of the most decisive factors in the subsequent extraction. The theoretical calculation results show that the temperature of the peak total crystallization rate will decrease 5K with basicity increasing 0.1. The relation between cooling conditions and grain size of spinels is also discussed. It is found that low cooling rate and high basicity benefit spinel crystal growth. And the non-isothermal crystallization kinetics results indicated that the restriction factors of spinel growth is that solid crystals accept new components from liquid-solid interfacial. While the sample was cooled down to 1250°C(1523K) at cooling rate of 5K/min, the crystal growth is consistent with Ostwald coarsening grew up law, and controlled by diffusion of particle.

By using of closed-form solution for predicting fatigue crack initiation life of a beam subjected to the transverse bending load in large range damage， fatigue crack initiation life of backup roll of four high mill is predicted. The method adopted in this paper is simple and effective. A new method is provided for predicting fatigue crack initiation life backup roll of four high mill.

Inhomogeneous materials with doubly periodic non-uniform cracks under antiplane shear is dealt with. By using conformal mapping technique and elliptic function theory, the stress field and stress intensity factor at the tip of each crack are derived in closed form. Numerical examples show the influences of some microstructure parameters of crack distribution on stress intensity factor.

The sorption and desorption characteristics of four kinds of organic phosphorus with different molecular structures (glycerophosphate (GP), glucose-6-phosphate (G6P), adenosine triphosphate (ATP), and myo-inositol hexakisphosphate (IHP)) on three kinds of aluminum (oxyhydr)oxides (amorphous Al(OH)3, boehmite, and alpha-Al2O3) were studied. The underlying mechanisms were also illustrated. Results showed that the maximum sorption amounts of OP onto Al (oxyhydr)oxides, on a per gram dry weight basis, decreased as following: amorphous Al(OH)3boehmitealpha-Al2O3. This mainly related to the mineral crystallinity and surface heterogeneity. With the exception of sorption of IHP on amorphous Al (OH)3, the maximum sorption density decreased with increasing molecular weight (MW) of OP, following the order: GPG6PATPIHP. However, the sorption amount of IHP on amorphous Al (OH)3 was much higher than those of other OP, due to the transformation of surface complexes of IHP to surface precipitation and thus enhancing the sorption. The sorption kinetics results showed that sorption of OP underwent the first onset rapid sorption, i. e. a certain amount of sorption occurred within an onset extremely short period, and a following long and slow sorption process. Amorphous Al (OH)3 had the greatest onset rapid sorption density, and the onset rapid sorption density of OP on Al (oxyhydr) oxides decreased with increasing MW. Desorption capacities of OP by KCl and citrate solutions related to the surface affinity between OP and boehmite. Initial desorption percentages by KCl decreased in the order: G6P (10.53%)GP(6.91%)ATP (3.06%)IHP (0.8%). The maximum desorption percentages of OP by citrate were 4-5 times greater than those by KCl. During resorption process of P by KCl, the maximum desorption rate achieved after a fast desorption in a few hours, followed by diffusion-resorption during which the desorption percentage gradually decreased. Specially, both diffusion-resorption and surface precipitation promoted the resorption of IHP on mineral surface. Conclusively, the strong specific sorption of OP occurs on the surface of Al (oxyhydr) oxides, and molecular structure and size of OP as well as the crystallinity and crystal structure of minerals are the key factors affecting the interfacial reactions and environmental behaviors of OP.

Applied fatigue damage mechanics and finite element method to study the fatigue crack initiation life problems of component. Fatigue crack initiation life is obtained by using the method of additional load, just a stiffness matrix calculation, greatly reducing the workload of calculation. With the damage degree of the critical element partitioning step of the damage evolution, the damage degree increases unceasingly obtains the corresponding, corresponding to the stress field, strain field and the load matrix, and then to calculate the equivalent stress, the application of damage evolution equation for calculating fatigue crack forming life corresponding. Until the damage degree of the critical element to 1 so far, the fatigue crack initiation life is obtained by adding the fatigue crack initiation lives with different damage variable.

Acid birnessite was treated with Na4P2O7 at pH 2, 4, 5 respectively. After the treatments, the species and content of manganese ion in the complex solution, and the variation of average oxidation state (AOS) of Mn in birnessite, and the amount of adsorbed Pb2+ and released Mn2+, H+ during the Pb2+ adsorption were investigated. The results indicate that after acid birnessite, the AOS of Mn is 3.670 which is treated by Na4P2O7 at different pH, Mn( III) located in the layer edge and part of Mn(III) located in the interlayer are released to the solution through complexation with Na4P2O7. The content of Mn(III) in the structure of original birnessite is very low. Small amount of Mn(II), which accounts for 4.70%-7.46% in the molar percentage of total released Mn, is also released simultaneously. The AOS of Mn of birnessites after treatment increases to 3.783 (pH 2), 3.786 (pH 4), 3.824 (pH 5) respectively. While the crystal structure of birnessite does not change after treatment, the amount of Mn(III) located above or below vacant cation sites decreases, and the amount of H+ located above or below vacant cation sites goes up in the structure of birnessites. The amount of vacant cation sites responsible for Pb2+ adsorption increases, which lead to the increase of the maximum amount of adsorbed Pb2+. Additionally, the distribution of Mn(III) in the structure of acid birnessite is deduced. About one sixth of Mn(III) locates in the layer edge, and five sixths of Mn(III) locates in the interlayer and the non layer edge.

Adsorption characteristics of mineral surface for heavy metal ions are largely determined by the type and amount of surface adsorption sites. However, the effects of substructure variance in manganese oxide on the adsorption sites and adsorption characteristics remain unclear. Adsorption experiments and powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) were combined to examine the adsorption characteristics of Pb2+, Cu2+, Zn2+ and Cd2+ sequestration by birnessites with different Mn average oxidation state (AOS), and the Mn AOS dependent adsorption sites and adsorption characteristics. The results show that the maximum adsorption capacity of Pb2+, Cu2+, Zn2+ and Cd2+ increased with increasing birnessite Mn AOS. The adsorption capacity followed the order of Pb2+Cu2+Zn2+Cd2+. The observations suggest that there exist two sites on the surface of birnessite, i. e., high-binding-energy site (HBE site) and low-binding-energy site (LBE site). With the increase of Mn AOS for birnessites, the amount of HBE sites for heavy metal ions adsorption remarkably increased. On the other hand, variation in the amount of LBE sites was insignificant. The amount of LBE sites is much more than those of HBE sites on the surface of birnessite with low Mn AOS. Nevertheless, both amounts on the surface of birnessite with high Mn AOS are very close to each other. Therefore, the heavy metal ions adsorption capacity on birnessite is largely determined by the amount of HBE sites. On birnessite surface, adsorption of Cu2+, Zn2+, and Cd2+ mostly occurred at HBE sites. In comparison with Zn2+ and Cd2+, more Cu2+ adsorbed on the LBW sites. Pb2+ adsorption maybe occupy at both LBE sites and HBE sites simultaneously.

In order to study the effects of transition metal ions on the physic-chemical properties of manganese dioxides as environmental friendly materials, three-dimensional nano-microsphere cobalt-doped birnessite was synthesized by reduction of potassium permanganate by mixtures of concentrated hydrochloride and cobalt (II) chloride. Powder X-ray diffraction, chemical analysis, N2 physical adsorption, field emission scanning electron microscopy (FE-SEM) and X-ray photoelectron spectra (XPS) were used to characterize the crystal structure, chemical composition and micro-morphologies of products. In the range of molar ratios from 0.05 to 0.20, birnessite was fabricated exclusively. It was observed that cobalt incorporated into the layers of birnessite and had little effect on the crystal structure and micromorpholgy, but crystallinity decreased after cobalt doping. Both chemical analysis and XPS results showed that manganese average oxidation state decreased after cobalt doping, and the percentage of Mn3+ increased. Co(III) OOH existed mainly in the structure. With the increase of cobalt, hydroxide oxygen percentage in molar increased from 12.79% for undoped birnessite to 13.05%, 17.69% and 17.79% for doped samples respectively. Adsorption capacity for lead and oxidation of arsenite of birnessite were enhanced by cobalt doping. The maximum capacity of Pb2+ adsorption increased in the order HB (2 538 mmol/kg)CoB5 (2798 mmol/kg)CoB10 (2932 mmol/kg)CoB20 (3 146 mmol/kg). Oxidation percentage of arsenite in simulated waste water by undoped birnessite was 76.5%, those of doped ones increased by 2.0%, 12.8% and 18.9% respectively. Partial of Co3+ substitution for Mn4+ results in the increase of negative charge of the layer and the content of hydroxyl group, which could account for the improved adsorption capacity of Pb2+. After substitution of manganese by cobalt, oxidation capacity of arsenite by birnessite increases likely due to the higher standard redox potential of Co3+/Co2+ than those of Mn4+/Mn3+/Mn2+. Therefore, Co-doped birnessite is more applicable for the remediation of water polluted with heavy metal ions, implying new methods of modification of manganese dioxides in practice.

Cr(III) could be oxidized only by manganese oxide minerals as natural inorganic oxidants in nature, and so the rate and mechanism of interaction between manganese oxide minerals and Cr(III) were widely concerned. The effects of Mn(III) in birnessites, the most common Mn oxide mineral in the environment, on the rate of Cr(III) oxidation with birnessites and the kinetic characteristics were investigated through batch kinetic technique. The results show that Cr(III) oxidation rate follows a pseudo-first-order reaction, and the apparent rate constant K(obs), is 0.031 3 min(-1) when the average oxidation state (AOS) of Mn is about 3.50 in birnessite. When the birnessite is pretreated with Na4P2O7 solution, and the Mn(III) can be complexed out from the solid oxides. Therefore the content of Mn(III) in the birnessites decreases and the AOS of manganese increases. The AOSs of Mn for the pretreated birnessites increase from 3.50 to 3.63, 3.73 and 3.78 when the concentrations of Na4P2O7 are about 10, 20 and 50 mmol/L respectively. The Mn(III) content does not affect the initial oxidation rate of Cr(III) markedly, although oxidation amount of Cr(III) increases with the AOS of Mn. The apparent rate constants for the corresponding pretreated birnessites are 0.035 1, 0.032 5 and 0.0309 min(-1) respectively. The oxidation rate of Cr( III) is markedly influenced by the amount of Mn(III) produced in the transformation process of Mn(VN) --Mn(III). The newly formed Mn(III) is complexed by Na4P2O7 and the oxidation rate decreases to 45%-88%. The lower content of Mn(III) in birnessites, the more Mn(III) newly formed from the transformation of Mn(IV) is complexed out from the minerals, and the greater amplitude in the decrease of Cr(III) oxidation rate. Thus the newly formed Mn(III) is highly active and possesses fast rate of electron transfer, however the rate of electron transfer in the transformation process of Mn(IV) --Mn(III) is relatively slow. It could be deduced that the controlling step of initial oxidation rate of Cr(III) with birnessites may be the electron transfer process of Mn(IV) --Mn(III).

Vacant sites in Mn oxides, commonly occur in soils, play an important role in their heavy metal adsorption behavior. The dependence of Pb2+ adsorption capacity for the synthesized birnessites and their d110-interplanar spacing on the respective Mn average oxidation state (AOS), and the relationship between Pb2+ adsorption and the Mn2+, H+, K+ released during adsorption were investigated. The results show that Mn AOS of birnessites apparently reflects their amount of vacant sites which largely account for the Pb2+ adsorption. Significant positive correlation between Pb2+ adsorption capacity and the Mn AOS of corresponding birnessites (r = 0.97790.6614, n = 14, alpha = 0.01), negative correlation between d110 spacing and the Mn AOS (r = -0.9035-0.6614, n = 14, alpha = 0.01), and significant positive correlation between Pb2+ adsorption and the Mn2+, H+, K+ released during adsorption(r = 0.99620.6614, n = 14, alpha = 0.01) are found. The vacant sites amount increases with Mn AOS for birnessites, which causes the increase of Pb2+ adsorption. Therefore, the Pb2+ adsorption capacity of birnessite is largely determined by the amount of vacant sites, from which Mn2+, H+, and K+ released during adsorption are mostly derived.