| In our country, the low concentration of sulfur dioxide smoke, which produced in the smelting of lead and antimony sulfides concentrates, is hard to make acid, and it caused serious environment pollution. In the thesis, a new smelting process of lead, antimony ,and bismuth sulfides concentrates with free sulfur dioxide- reducing-matting smelting by use of pyrite cinder as a fixed sulfur agent has been proposed. In the process, the matting reactions should occur in strong reducing atmosphere. The principle and technics of this process for smelting lead sulfide and Jamesonite concentrates and the treating ferrous matte has been researched, and some valuable conclusions is obtained.The thermodynamic calculation of reducing-matting reactions with ferric oxide as a fixed sulfur agent has been done. It is firstly found that the reducing-matting reactions of lead sulfide, antimony sulfide, Jamesonite, and bismuth sulfide are feasible, but is infeasible for zinc sulfide. To be based on JIEMUJIN model the formula for calculating distribution coefficients of impurity elements between metals phase andferrous matte phase was got: D = and the calculated results aremet with experimental data. The solubility of lead in the system of FeS-Na2S was determined at temperature of 1373K and 1473K. It is important for controlling content of lead in the ferrous matte.In the experiments of the new process smelting with lead and antimony sulfide concentrates without sulfur dioxide, pyrite cinder rich in ferric oxide was firstly used for a fixed sulfur agent in stead of purity ferric oxide, and which is important for solving problems on the pollution of low concentration of sulfur dioxide smoke and recovery of gold in the pyrite cinder containing gold and decreases the cost of the process, so that its industrial application becomes feasible.In the experiment of the reducing-matting smelting of lead sulfide concentrates the influence of the technics conditions such as smelting time and temperature, the addition of pyrite cinder and additive on the reducing-matting smelting is notable. Under the optimum condition of the table experiments, the direct recovery of lead and silver is higher than 88% and 70%, respectively, and the ratio of sulfur fixed is higher than 96%. The pilot test of the new process was conducted in a reverberator furnace with area of 1m2. In the case of the smelting scale being enlarged 1200 factors the new process is also feasible. A good result of the experiment was abtained that the direct and sum recovery of lead is 87.13%and 96.44%,respectively, the ratio of sulfur fixed is more than 96% and the content of sulfur dioxide in dust smoke is lower than thecountry standard. The content of copper and zinc in rude lead is lower than 0.05%, so the rude lead can be directly electrolyted for refining. But reverberator furnace has the disadvantage of lower heat efficiency and productivity and it is infeasible for this process.In the experiments of the reducing-mattig smelting on Jamesonite concentrate, sodium antimonate slag or alkali slag containing arsenic was firstly used as additive instead of soda and sodium sulfate, that is not only decreased the cost of the process, but also has great significance for treating alkali slag produced in alkali refining of rude lead ,rude antimony and their alloy. In the table experiment using soda and sodium sulfate as additive, the direct recovery of lead, antimony ,and silver is 68.50%,83.26%,and70%, respectively, and the sum recovery of metals and the ratio of sulfur fixed is more than 95% and 96%, respectively. In the experiment using sodium antimonite slag as additive, the direct recovery ratio of lead and antimony is 78.24%and 90.43%, respectively.In the experiment using alkali slag containing arsenic as additive, arsenic reacted with antimony and iron to produce a great amount of slag containing As, Fe , Sb and Pb,thereby, the recovery of metals decreased greatly. In the case of addition pyrite cinder being 70% of the theory amount the most high direct recovery of lead a...
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