Research On Hot-pressing Acidic Selective Leaching Technology Of High-iron-zinc Reduction Calcin

Guangxi Dachang indium-rich high-output marmatite years using hot acid leaching of high iron and zinc calcine,jarosite heavy iron,indium enrichment through volatilization into the second rotary kiln zinc oxide fumes,in addition to rail system huge,jarosite slag slag volume,resulting in the recovery of zinc,indium low for this situation need to develop new technology to improve the high-speed rail sphalerite comprehensive recycling levels.By self-motivated innovation and integrated innovation,basing on the previous research results and production experience,using the preponderant mineral resources of indium,zinc etc in Guangxi,the project has firstly proposed an technical approach applying reduction roasting and hot-pressing acid selective leaching to refine indium or zinc mineral bearing high content of iron.The core of the approach involves decomposing the zinc ferrite in zinc concentrate thoroughly by reduction roasting in the first place,selective leaching and deironing under high pressure at high temperature.The technology has achieved remarkable effects on both separating iron from indium or zinc and comprehensive utilization of iron,briefed the process and recovery rate of refining indium and zinc,acquired the goals of both notable energy efficiency and process simplification.The project has carried out reduction roasting and hot-pressing acid selective leaching treatment to refine zinc mineral,varied the experimental factors,including reducibility of reduction roasting,acid to mineral ratio,temperature,oxygen partial pressure and reaction time,and investigate their effects to provide a basis for the industrialization of the project.The experimental results have indicated the conclusions below:1.The hot-pressing acid selective leaching treatment is technically feasible with a high leaching rate of indium and zinc,while separating the iron from zica thoroughly.The optimal treatment conditions demonstrated by single-factor experiment:reducibility of reduction roasting>90%,acid to mineral ratio is 1:1,temperature is 195℃,oxygen partial pressure is 0.4Mpa,and reaction time is 180mins.2.The zinc calcine must be reduction roasted before hot-pressing acid selective leached with a ferric reducibility>80%to enrich iron in slag.The slag rate is 38%with an average iron grade of 51%,which can be used as ironmaking or construction material.3.On the premise of certain leaching rate of indium and zinc,control the acid to mineral ratio to lower the iron concentration under 1g/L,which will increase the iron grage to 56%and reduce the sulphur content in slag.4.Hot-pressing temperature has a primary effect on the leaching rate of indium and zinc,when which is above 190℃,all targets may be well acquired as 98.6%,91.5%and 6.3%leaching rate of zinc,indium and iron each,a 49.6%iron grade in slag and a 34.3%slag rate.5.Oxygen partial pressure affects the result slightly.The optimal leaching rate of indium is attained when the oxygen partial pressure is 0.4Mpa,and the lowest sulphur content in slag is attained when the general pressure is above 1.8Mpa.6.Comprehensive test results obtained zinc leaching rate of 98.9%,the leaching rate of 91.4%indium,iron leaching rate of 6.4%,obtained 51.15%grade iron slag,iron slag sulfur content of 2.13%.7.The new technology could add 1,560 tons of zinc,indium yield 8.82 tons,the new annual profit of 35.14 million yuan.