I. Introduction Zinc has a wide range of uses and plays an important role in the national economy [1] . With the development of the economy, once resources are depleted, the use of secondary resources becomes inevitable [2] , wet zinc smelting has accounted for more than 80% of the world's total zinc smelting, is the development direction of the world zinc smelting production, and wet method zinc zinc leaching residue in output caused by environmental pollution and waste of resources [3] enhance dross valuable metals recycling, to maximize use of mineral resources, increase economic efficiency. A certain group company in Hunan is a production enterprise integrating mining, selection and smelting. The company produces tens of thousands of tons of metal products every year, and also emits hundreds of thousands of tons of smelting slag. The zinc grade in zinc conventional leaching slag is as high as 16.8. %, commissioned by the company, the zinc in the zinc leaching residue was subjected to hot acid leaching and flotation recovery tests, and achieved good results. Second, the nature of raw materials The test raw materials were from the wet zinc slag of a smelter in Hunan. The raw materials contained 16.8% zinc and 17.8% iron . X-ray diffraction analysis showed that the zinc in the raw material was mainly in the form of zinc ferrite (ZnFe 2 O 4 ) and zinc sulfide (ZnS). There was no single zinc oxide (ZnO). After particle size analysis, the particle size of the smelting slag was -0.074mm accounts for 90.5%. Third, the experimental results and analysis (1) Effect of temperature on leaching rate Figure 1 The effect of temperature on the dip The experimental results show that the zinc leaching rate increases with the increase of leaching temperature. When the temperature is 90 ° C, the zinc leaching rate reaches 72.0%, and the temperature continues to increase. The zinc leaching rate is not significantly increased, but this also consumes a large amount of energy and increases the cost, so the leaching temperature is preferably 90 ° C. (B) the impact of time on the leaching rate Under the conditions of liquid-solid ratio of 3:1, leaching temperature of 90 °C and initial acid concentration of 250 g/L, the effects of different leaching time on zinc leaching rate were investigated. The results of leaching at different times are shown in Fig. 2. Figure 2 Effect of time on leaching The test results show that as the leaching time increases, the zinc leaching rate increases. The leaching rate reached 73.3% at 3 hours of leaching, and the leaching time continued to increase. The leaching rate of zinc was not significantly increased. The industrial cost of leaching time was also greatly increased, so the leaching time was determined to be 3 hours. (3) Effect of liquid-solid ratio on leaching rate The leaching temperature was 90 ° C, the sulfuric acid concentration was 250 g / L, and the leaching time was 3 hours. The effect of different liquid-solid ratio on zinc leaching rate was investigated. The test results are shown in Fig. 3. Figure 3 Effect of liquid-solid ratio on leaching rate The test results show that with the increase of liquid-solid ratio, the zinc leaching rate increases. When the liquid-solid ratio is 4:1, the leaching rate of zinc reaches 74.2%, and the liquid-solid ratio continues to increase. The increase is not obvious, but this will consume a large amount of sulfuric acid, which will increase the residual acid of the leachate, which is unfavorable for the subsequent process. So choose a liquid to solid ratio of 4:1. (4) Effect of initial acid concentration on leaching rate The liquid-solid ratio was 4:1, the leaching temperature was 90 ° C, and the leaching time was 3 hours. The results of examining the zinc leaching rate of different acidity are shown in Fig. 4. Figure 4 Effect of initial acid concentration on leaching rate The results show that with the increase of sulfuric acid dosage, the leaching rate of zinc increases. When the concentration of sulfuric acid is 310g/L, the leaching rate of zinc has reached 75.3%, and the concentration of leaching acid is continuously increased. The leaching rate of zinc is not improved much. When the initial acid concentration in the test is 310 g/L, it is optimal. (5) Flotation test The leaching rate of zinc by hot acid leaching has reached 75.3%, but the hot acid leaching slag still contains 4.12% of zinc. X-ray diffraction analysis indicates that zinc in the hot acid leaching residue exists in the form of zinc sulfide, which leads to hot acid leaching. The reason why zinc cannot be completely dissolved. In order to additionally recover the part of zinc sulfide, it is treated by flotation method, and the flotation experiment adopts a rough selection and a selected test procedure. - roughing conditions Pharmacy: lime 3000g / t, copper sulfate 1000g / t, xanthate 200g / t, 2 # oil 40g / t, roughing index: selection agent concentrate grade conditions for 9.7%, 92.4% recovery Therefore, the original rough-concentrated concentrate was further tested. ——Select a coarse concentrate, add 500g/t sodium silicate (NaSiO 4 ) as dispersant and inhibitor, the concentrate grade is 18.9%, and the recovery rate is 89.4%. Fourth, the conclusion ——The zinc in the wet smelting zinc slag of a smelting plant mainly exists in the form of zinc ferrite and zinc sulfide; ——With hot acid leaching, the zinc leaching rate is 75.3% under the conditions of leaching temperature 95 ° C, initial acid concentration 310 g / L, liquid-solid ratio 4:1, leaching for 3 hours, and image analysis shows that hot acid leaching Zinc ferrite has been completely dissolved under the conditions, but zinc sulfide is difficult to dissolve; ——Recovering zinc sulphide from hot acid leaching residue by flotation method, using one rough selection and one selected flotation process, yellow medicine, lime, copper sulfate, sodium silicate, 2 # oil as flotation agent, zinc can be obtained The concentrate grade is 18.9%, and the recovery rate of zinc sulfide is 89.4%. references: [1] Tu Hailing, Zhao Guoquan, Guo Qingwei. Nonferrous Metallurgy, Materials, Recycling and Environmental Protection [M]. Chemical Industry Press, 2002, 66. [2] Liu Qing, Zhao Guodong, Zhao Yicai. Technology and Status Quo of Valuable Metal Recovery in Nonferrous Metallurgical Waste Residues [J]. Nonferrous Metals Design and Research, 200(3): 22-26. [3] Liu Bin, Wang Weitao. Discussion on the problem of leaching slag in wet zinc smelting process[J]. Sichuan Environment, 2007(2): 105-108. Power Steering Pump Pulley,Steel Spinning Pk Pulley,Spinning Steering Pump Pulley,Auto Power Pulley Taizhou Chenhui Machinery Manufacturing Co., Ltd , https://www.chenhuipulley.com
Selecting and smelting combines zinc recovery from zinc leaching residue