Yunnan A Lead And Zinc Flotation Process Optimization Studies

The lead-zinc ore locates in a certain place of Yunnan province, of which the crude ore includes 1.46% of lead,51.28% oxidation rate of the zinc,4.38% of zinc, and 11.75% oxidation rate of zinc. Because of the problems of the low grde of lead concentrate,only 38.38% , and the high grade of zinc,6.84% hapenning due to the characteristic of the crude ore changed, so it is necessary to improve the old process flowsheet.The exploring tests prove that the galena of the crude ore is floatable comparatively, the recovery of lead is low, and the low grade concentrate of lead includes quite a little zinc since the difficulty of separating lead and zinc due to about 20% easy floatable sphalerite in crude ore.Firstly, the study of collective flotation is carried out because of many advantages for using collective flotation, such as reducing the numbers of floatation machine, convenience of recycling water and saving reagent and so on. By the tests, it is found that the results of separating lead and zinc is not very satisfactory, and lead-zinc includes each other seriously. For the problems of Inefficient lead-zinc separating without dereagent,the lead-zinc separating tests by regrinding the collective concentrate, and by reagent removal with Na2S, adsorption with carbon.But the results are not good. The separation of lead and zinc is still difficult by using conventional way of reagent removal.For reaching regular concentration of lead and zinc, we had a preferential flotation test for optimization of process.Through the experiment on selective flotation, we found that the grade and recovery of lead concentrate is low, and the grade of zinc is high in lead concentrate. On the base of analyzing the possibility, the experiments on technology optimum that is the comparisons of inhibitors and its locations, raising the quality of the lead concentrate, and stage grinding and stage separation are carried out. Tough the index of lead concentrate is enhanced, the radical solution is still unsolved. In the experimental study of raising the recovery of lead, optimum Na2s is added before the flotation, and easily floatated plumbous oxide and plumbous sulfide is flotated together. When sodium sulfide is fed in the milling pit, not only the grade and recovery of lead is graduated up remarkably, but also the zinc contents of lead concentrate is lower. Further investigate shows that recovery of lead varies a little, while grade of that raises more than 2% and zinc contents are lower markedly along with increase of sodium sulfide.The flow recommended is selective flotation,It is reached that the lead grade of 41.56%,recovery of 45.80%,and contents 3.86% of zinc in lead concentrate,and that of zinc concentrate is the zinc grade of 55.65%,recovery of 83.73%,and contents 1.74% of lead by the test of closed ciruit. The former is not sastisfactory enough, but the latter is better.by means of which the grade of lead is raised above 3% and that of zinc reduced about 3% respectively compared with the old one, and the solution of high grade of zinc in lead concentrate is improved. But more research is still need to be carried out because the grade and recovery of lead concentrate are low.