Research On Key Technology In The Beneficiation Of Sn-bearing Refractory Lead-zinc Mine In Southeast Yunnan

Southeast region of Yunnan province has abundant mineral resources, which are rich in tin, silver, indium, lead, zinc, tungsten, copper etc., southeast polymetallic deposits of Yunnan mainly locate in Gejiu, Bainiuchang and Dulong. This thesis studied on refractory lead-zinc mineral containing tin from Mengzi Bainiuchang, Yunnan province, the electrochemical flotation behavior of various sulfides and flotation performance of tin mineral were detailedly investigated. On this basis, flotation separation process of the ore has been designed and forms the key technology of mineral processing of refractoty lead-zinc sulfides containing tin of southeast region of Yunnan. The technology has successfully applied to production practice, providing theoretical guidances and feasible basises for mine practical production.The flotation behavior of galena, marmatite, pyrrhotite, pyrite and arsenopyrite of Bainiuchang were investigated and ascertained. Butyl xanthate, diethyldithiocarbamate, ammonium butyl aerofloat and aniline aerofloat have different collecting abilities to these five kinds of lead-zinc sulfides. On the weak basic condition, aniline aerofloat as collector has favarable selective performance to galena. On the alkaline condition, diethyldithiocarbamate have better selective performance only to galena, and the selective performance of ammonium butyl aerofloat is worst. The relationship between pulp potential and flotation behavior was studied, the results indicate that aniline aerofloat as collector, potential ranging from0.05mV to0.02mV is propitious to separate galena from the other sulfides. Diethyldithiocarbamate as collector, when lime conditions pulp pH=12.0and potential is lower than0.175V, galena can be separated from the other sulfides. Electrochemical testing, infrared spectroscopy, cyclic voltammetry testing were applied to study the oxidation mechanism of mineral surface in the presence of collector, probe into the adsorption reactions between collector and minaral surface, and their resultants on mineral surface.Experimental results of cassiterite show that, Benzohydroxamic acid collects micro-fine cassiterite effectively and its dosage is also small, but its collecting ability to quartz is also very strong. Ligninas inhibitor of quartz and calcite has significantly inhibitory effect, and has little effect on the flotation of cassiterite. The overflow sample of classification of gravity separation are deslimed and desulfurized by concentration. By flotation, the grade and recovery of tin concentrate reach45.71%,73.46%, respectively. With flotation collumn, the grade and recovery of tin concentrate reach42.68%,82.87%, respectively. Comparing to flotation machine, not only the mineral processing index is better but also technological process and reagent system are simpler, thus the mineral processing cost reduces greatly. The results of gravity separation indicate that the ore of Bainiuchang need to be desulfurizes before gravity separation due to its high sulfur concentration, therefore, higher grade and recovery of tin concentration can be achieved, sulfur concentration also can be recovered. These are beneficial to comprehensive recovery of resources.Bainiuchang mainly produces two different types of lead-zinc sulfides, one is with silver concentration of100g/t, the other is with silver concentration of65g/t. Base on these two types, potential-controlled flotations of low base and high-alkali were developed. When pulp pH is greater than12, pulp potential is about130mV, xanthate and diethyldithiocarbamate as collector and lime as regulator of pH, flotation separation of vanadium from other mineral can be achieved. The reagent system of high-alkali process is simple, but to lead-zinc ore, the recovery of silver is slow with this method. Aniline aerofloat and diethyldithiocarbamate as collector, zinc sulfate and sodium sulfite as inhibitor, under the condition of potential-controlled flotations of low base, the recovery of silver is enhanced greatly. Two production processes have gained favorable production targets of lead and zinc. In2010, the second plant mainly processed lead-zinc ore with high concentration of silver, the grade of lead concentrate reached52.62%and its recovery reached83.67%, the recovery of silver reached60.47%; the grade of zinc concentrate reached44.70%and its recovery reached93.59%. In2010, the third plant mainly processed lead-zinc ore with low concentration of silver, the grade of lead concentrate reached56.13%and its recovery reached80.15%, the recovery of silver reached51.12%; the grade of zinc concentrate reached45.31%and its recovery reached91.24%. using flotation collumn instead of flotation machine, the grade of lead concentration increased by8%, the grade of zinc concentration increased by5%.Through this study, the electrochemical flotation behavior of complex sulphides has been complehensively and profoundly understood, which is helpful to promote the application of potential-controlled flotation and form a new advanced technology of flotation separation of complex poly-metallic lead-zinc sulfides.This study was strongly supported by industrialization base of Central South University-Mengzi Mining limited liability company...