A hydrometallurgical process for the separation of lead and bismuth from lead bismuthite

Abstract A hydrometallurgical process to efficiently separate and recover bismuth and lead from lead bismuthite was proposed. It included the dissolution of lead bismuthite in a solution containing 4.2 mol/L HNO 3 and 5.0 wt.% of carbamide at a temperature of 70–90°C followed by bismuth precipitation by adding lead carbonate to precipitate basic bismuth nitrate [Bi 6 O 4 (OH) 4 ](NO 3 ) 6 ∙ H 2 O of a technical grade. The lead‐containing solution was further evaporated to produce lead nitrate Pb(NO 3 ) 2 of a chemically pure grade, while the basic bismuth nitrate was further purified from metal impurities. Basic bismuth nitrate was dissolved in a ~6.0 mol/L HNO 3 solution at a temperature of 60–70°C, diluted with distilled water two times, and mixed with an aqueous ammonium carbonate solution to adjust the pH to 0.9 at a temperature of 55°C and to precipitate bismuth. After washing and drying of the precipitate at a temperature of 90–100°C, the high purity basic bismuth nitrate [Bi 6 O 5 (OH) 3 ](NO 3 ) 5 ∙ 3H 2 O was obtained. The large‐scale laboratory trials confirmed the relevance of the proposed technology for hydrometallurgical processing of lead‐ and bismuth‐containing raw materials. It is an easy and economical way to produce high purity bismuth and lead compounds.