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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]

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]