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Aiming at the problem of over-grinding and under-grinding and the influence of grinding mode and feed size on ore grinding effect. Cassiterite polymetallic sulfide ore was taken as the research object. The grain size distribution of grinding minerals and grinding behavior characteristics were explored based on batch grinding test, by changing grinding method, feed sizes, grinding time and other factors affecting grinding. It was shown by the results that attrition grinding process was a low-energy grinding, the force of ore was small, and the under-grinding was easy to occur, whereas drop grinding and impact grinding processes were high-energy grinding, the ore was subjected to greater force, more fully broken, easy to occur over-grinding phenomenon. The variation amplitude of grinding technical efficiency E and grinding mineral substance tw was stable with grinding time under grinding conditions, and the product size distribution was uniform. Grinding technical efficiency E and grinding product t10 were changed obviously with the grinding time under drop grinding and impact grinding, and the change range was large, and in general, the two grinding indexes are greater than that of attrition grinding. Complicated and without obvious rule was the relationship between the grinding behavior of ore and the feeding size. A theoretical basis for the subsequent research on the strength and interaction of attrition and impact forces in the dropping state was provided by the research results. [ABSTRACT FROM AUTHOR]

In this paper, zinc calcines, sulfuric acid, ferric nitrate nine-hydrate, zinc nitrate hexahydrate, titanium oxide sulfate, sodium hydroxide and ammonia water were selected as raw materials, and the methods of sulfuric acid leaching and chemical coprecipitation were used to prepare purified zinc ferrite, synthetic zinc ferrite, synthetic titanium dioxide and its composite with purified zinc ferrite. And characterized by BET, UVVis and FTIR. The results showed that: SO42- existed in purified zinc ferrite. Purified zinc ferrite, synthetic zinc ferrite and purchased had different specific surface area, pore volume and average pore size. The specific surface area of synthetic zinc ferrite decreased with the increase of calcination temperature. The three kinds of zinc ferrite had good absorption of ultraviolet light and visible light. Purchased ferric acid had the strongest absorption of UV light and synthetic zinc ferrite had the strongest absorption of visible light, and purified zinc ferrite had the absorption of UV light and visible light between the two. The specific surface area of titanium dioxide prepared by chemical coprecipitation method was greatly affected by calcination temperature. With the increase of calcination temperature, the specific surface area decreased from 123.633 to 28.036m2·g-1, and the average pore diameter was less affected by calcination temperature. For the zinc ferrite/titanium dioxide composite prepared by chemical coprecipitation method, a certain amount of purified zinc ferrite was added to facilitate the absorption of visible light by titanium dioxide.

In this paper, sulfuric acid leaching high iron zinc calcine was used to prepare and purify zinc ferrite, high temperature roasting method was used to prepare synthetic zinc ferrite, and sol-gel method was used to prepare TiO2. The properties of the prepared samples ware characterized by XRD, FT-IR, BET, SEM and other methods. The results show that the synthetic zinc ferrite is pure zinc ferrite, and the purified zinc ferrite contains impurities PbSO4. The TiO2 crystal form prepares at the calcination temperature of 300~550°C is basically the same, and the crystal form transformation occurs at the calcination temperature of 550~600°C. TiO2 samples calcines at 400°C (T400) have higher specific surface area, larger total pore volume and average pore diameter. The crystalline degree of synthetic zinc ferrite is high, the micropores on the crystal surface are closed, and the grains bond with each other. The specific surface area, total pore volume and average pore diameter of purified zinc ferrite are larger than those of synthetic zinc ferrite. The effects of specific surface area, pore volume and pore structure on the adsorption capacity and catalytic efficiency are as follows: T400> purified zinc ferrite > synthesized zinc ferrite.

In this paper, the methods of sulfuric acid leaching and chemical coprecipitation were used to prepare products such as purified zinc ferrite, synthetic zinc ferrite, synthetic titanium dioxide and its complex with purified zinc ferrite. The morphology and microstructure of the above samples were characterized and analyzed by XRD and SEM. The results showed that the purified zinc ferrite contained a small amount of ZnO, SiO2, Al2O3 and PbSO4. Its particle size was the largest and the crystallinity was the best, but the surface was not smooth, the particle size distribution was not uniform and there was agglomeration phenomenon. The purchased zinc ferrite had high purity, the smallest particle size and the worst crystallinity. Its surface was smooth, particle size distribution was uniform, and it was loose and porous. The synthetic zinc ferrite had high purity, smooth surface, uniform particle size distribution and obvious agglomeration. The prepared titanium dioxide had no other impurities, good crystallinity, smooth surface and certain agglomeration phenomenon. For the zinc ferrite/titanium dioxide composite, adding a small amount of purified zinc ferrite would change the crystallinity of titanium dioxide, but it had little effect on the grain size of titanium dioxide. The surface was rough, the particle size distribution was not uniform, and there was agglomeration phenomenon.

With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(VI) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(VI). The waste amidoxime resin was first modified with H3PO4 and ZnCl2, and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(VI) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(VI) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(VI) to Cr(III) and decrease the toxicity of Cr(VI) during adsorption. PPR-Z exhibited Cr(VI) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(VI) adsorption are the chemical reduction of Cr(VI) into Cr(III) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(VI) pollution and realizes the concept of "treating waste with waste". [ABSTRACT FROM AUTHOR]

Gossan ore is typically abandoned after mining, which not only increases mining production costs but also wastes mineral resources, and its long-term accumulation can easily lead to environmental pollution hazards. Therefore, this paper takes zinc-containing gossan ore as the research object and, based on the high content of zinc and iron minerals in gossan ore, this study conducts a roasting experiment to prepare ZnFeO4. X-ray diffraction is used to characterize and analyze the ZnFeO4 sample prepared by roasting zinc-containing gossan ore. The experimental results indicate that controlling the particle size of the roasted ore sample to −0.074 mm can effectively remove impurities and facilitate the reaction. The influence of roasting temperature and time on the formation of ZnFeO4 is remarkable. The conditions for roasting zinc-containing gossan ore to maximize the ZnFeO4 content are as follows: −0.074 mm particle size ore sample, reaction zinc/iron molar ratio of 1:2, mechanical activation time of 120 min, roasting temperature of 1050 °C, and roasting time of 120 min. These findings provide new ideas for the utilization of gossan ore and lay a theoretical foundation for the efficient development and utilization of difficult-to-select zinc-containing gossan ore. [ABSTRACT FROM AUTHOR]