New Process Study On Preparation Of Bismuth Production From Lead Dust Bearing Bismuth

A novel process for treating the smoke dust containing Bi-Pb to produce bismuth chemical products is developed. The first stage is a reduction-chlorination-distillation process simply named as CR process, in which arsenic distilled in to distillate for producing Cu3(AsO4)2, Bi,Cu, Zn, Cd, and et al is going into leached solution, Pb, Ag and et al is going into leached residue, but Sn enter into a water washed solution. The leached solution is hydrolyzed to obtain BiOCl for producing bismuth chemical products. At the same time, the valuable elements including Cu, Ge, Sn, Zn, Cd and Pb are comprehensively recovered in the forms of copper sulfide slag, germanium concentrate, tin concentrate, grade zinc oxide, copper-cadmium residue and lead slag, respectively.The process has good comprehensive utilization and high metal recovery, where the recoveries of Bi, Pb, Zn, Cu, Sn, Cd, As elements can reach 99.36%, 99.23%, 86.81%, 98.34%, 75.68%, 91.56% and 98.67%, respectively. Bismuth chloroxide is used to prepare bismuth nitrate by removing chlorine, which transforms bismuth hyponitrate, then bismuth hypocarbonate and finally bismuth oxide by calcinations. The metal impurities of bismuth nitrate, bismuth hyponitrate, bismuth hypocarbonate and bismuth oxide products achieve analytic grade, and only anion impurities of part products need be further removed. Besides, entirely avoiding environmental protection of noxious Pb and As, so CR method is a benign environment method, where arsenic product is in the form of copper arsenate, tin product is the concentrate containing 70% Sn by use of adding NH4Cl toenrich tin in washing solution.