Current situation and development trend of titanium metal industry in China

Titanium metal and alloy are key materials for technological development,which significantly promote the development of the hightech economy in China.The consumption of high-end titanium materials and the developmental level of the titanium industry are important indexes of a country’s comprehensive power.However,at present,the application amount and level of high-end titanium materials in China are limited by many factors,including the dependence of raw materials on imports,high processing cost,and structural imbalance of products.Based on the characteristics of titanium resources and the current situation of the titanium industry,the whole titanium industrial chain in China should be updated.Improving the quality of raw materials is important to produce low-cost,high-end titanium materials using titanium resources with high calcium and magnesium contents in the Panxi region.In addition,the steel-titanium joint production is a vital step to reduce the processing cost of titanium materials.Moreover,the consumption structure of titanium materials should be completed to expand their application.Gradually implementing these suggestions,the overall level of China’s titanium industry will be greatly improved,thereby rapidly establishing an advanced scientific and technological country.

Catalytic mechanism of manganese ions and visible light on chalcopyrite bioleaching in the presence of Acidithiobacillus ferrooxidans

The bioleaching of chalcopyrite is low cost and environmentally friendly,but the leaching rate is low.To explore the mechanism of chalcopyrite bioleaching and improve its leaching rate,the effect and mechanism of manganese ions(Mn^(2+))and visible light on chalcopyrite mediated by Acidithiobacillus ferrooxidans(A.ferrooxidans)were discussed.Bioleaching experiments showed that when both Mn^(2+)and visible light were present,the copper extraction was 14.38%higher than that of the control system(without Mn^(2+)and visible light).Moreover,visible light and Mn^(2+)promoted the growth of A.ferrooxidans.Scanning electron microscopy(SEM)and energy dispersive spectrometer(EDS)analysis revealed that Mn^(2+)promoted the formation of extracellular polymeric substance(EPS)on the surface of chalcopyrite,changed the morphology of A.ferrooxidans,enhanced the adsorption of bacteria on chalcopyrite surface with light illumination,and thus promoted the bioleaching of chalcopyrite.UV–vis absorbance spectra indicated that Mn^(2+)promoted the response of chalcopyrite to visible light and enhanced the catalytic effect of visible light on chalcopyrite bioleaching.Based on X-ray photoelectron spectroscopy(XPS),the relevant sulfur speciation of chalcopyrite before and after bioleaching were analyzed and the results revealed that visible light and Mn^(2+)promoted chalcopyrite bioleaching by reducing the formation of passivation layer(S_(n)^(2-)/S0).Investigation into electrochemical results further indicated that Mn^(2+)and visible light improved the electrochemical activity of chalcopyrite,thus increasing the bioleaching rate.

Chalcocite(bio)hydrometallurgy-current state,mechanism,and future directions:A review

There has been a strong interest in technologies suited for mining and processing of low-grade ores because of the rapid depletion of mineral resources in the world.In most cases,the extraction of copper from such raw materials is achieved by applying the leaching procedures.However,its low extraction efficiency and the long extraction period limit its large-scale commercial applications in copper recovery,even though bioleaching has been widely employed commercially for heap and dump bioleaching of secondary copper sulfide ores.Overcoming the technical challenges requires a better understanding of leaching kinetics and on-site microbial activities.Herein,this paper reviews the current status of main commercial biomining operations around the world,identifies factors that affect chalcocite dissolution both in chemical leaching and bioleaching,summarizes the related kinetic research,and concludes with a discussion of two on-site chalcocite heap leaching practices.Further,the challenges and innovations for the future development of chalcocite hydrometallurgy are presented in the end.

Inhibition of hematite on acid mine drainage caused by chalcopyrite biodissolution

Even though biodissolution of chalcopyrite is considered to be one of the key contributors in the formation of acid mine drainage(AMD),there are few studies to control AMD by inhibiting chalcopyrite biodissolution.Therefore,a novel method of using hematite to inhibit chalcopyrite biodissolution was proposed and verified.The results indicated that chalcopyrite biodissolution could be significantly inhibited by hematite,which consequently decreased the formation of AMD.In the presence of hematite,the final biodissolution rate of chalcopyrite decreased from 57.9%to 44.4%at 20 day.This in turn suggested that the formation of AMD was effectively suppressed under such condition.According to the biodissolution results,mineral composition and morphology analyses,and electrochemical analysis,it was shown that hematite promoted the formation and accumulation of passivation substances(jarosite and Cu2-xS)on chalcopyrite surface,thus inhibiting the biodissolution of chalcopyrite and limiting the formation of AMD.

Electrochemical behaviors of silicon wafers in silica slurry

The electrochemical behaviors of n-type silicon wafers pH value and solid content of the slurry on the corrosion of silicon in silica-based slurry were investigated, and the influences of the wafers were studied by using electrochemical DC polarization and AC impedance techniques. The results revealed that these factors affected the corrosion behaviors of silicon wafers to different degrees and had their suitable parameters that made the maximum corrosion rate of the wafers. The corrosion potential of （100） sttrface was lower than that of（111）, whereas the current density of （100） was much higher than that of（111）.

改性电炉钛渣矿相解构法制备富钛料新工艺研究

以氧化后的钛精矿电炉冶炼渣为研究对象,采用一段氟化氢铵浸出-二段盐酸浸出的新工艺制备可用于沸腾氯化生产的富钛料原料,从浸出反应热力学和改性钛渣浸出行为两方面进行了系统的研究。氟化氢铵浸出热力学研究表明,氟化氢铵浸出可分解硅酸盐和部分黑钛石,并形成CaMg_(2)Al_(2)F_(12),CaF_(2)和AlF_(3)沉淀,浸出后杂质元素硅主要以(NH_(4))_(2)SiF_(6)的形式进入到浸出液中。氟化氢铵浸出实验表明,在氟化氢铵浓度为15wt%、液固比为10:1、温度20℃、浸出时间2 h的条件下,Si,Al,Ti,Fe,Ca和Mg元素的浸出率分别为93.55wt%,28.03wt%,3.88wt%,20.50wt%,3.40wt%和2.45wt%。浸出渣中主要的物相为金红石、黑钛石和钙镁氟化盐。氟化浸出残渣的盐酸浸出热力学表明,CaMg_(2)Al_(2)F_(12),CaF_(2),AlF_(3)沉淀和剩余的黑钛石可溶解于盐酸溶液中。盐酸浸出实验表明,在盐酸浓度为20wt%、液固比为8:1、温度120℃、浸出时间2 h的条件下,Ca,Al,Mg,Ti,Si和Fe的浸出率分别为86.78wt%,62.33wt%,92.31wt%,18.08wt%,40.23wt%和75.36wt%。盐酸浸出后浸出渣主要物相为金红石,TiO2品位95.20wt%、CaO含量为0.49wt%、MgO含量为0.48wt%,满足沸腾氯化法对原料成分的要求。

Hollow spherical rare-earth-doped yttrium oxysulfate： A novel structure for upconversion

A facile biomolecule-assisted hydrothermal route followed by calcination has been employed for the preparation of monoclinic yttrium oxysulfate hollow spheres doped with other rare-earth ions （Yb3＋ and Eu3＋ or Er3＋）. The formation of hollow spheres may involve Ostwald ripening. The resulting hybrid materials were used for upconversion applications. The host crystal structure allows the easy co-doping of two different rare-earth metal ions without significantly changing the host lattice. The luminescent properties were affected by the ratio and concentration of dopant rare-earth metal ions due to energy transfer and the symmetry of the crystal field. The type of luminescent center and the crystallinity of samples were also shown to have a significant influence on the optical properties of the as-prepared products.