Process for recovering lead from lead-containing raw materials

• Main Author: KHODOV, NIKOLAI VLADIMIROVICH
• Format: Patent
• Language: English; French; German
• Published: 23.03.1994
• Edition: 5
• Subjects: CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION ORPROCESSING OF GOODS; FERROUS OR NON-FERROUS ALLOYS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; METALLURGY; PRETREATMENT OF RAW MATERIALS; PRODUCTION AND REFINING OF METALS; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; TREATMENT OF ALLOYS OR NON-FERROUS METALS

There is proposed a process for recovering lead, comprising the steps of: feeding molten caustic soda, lead-containing feed and an oxygen-containing gas into a reaction zone having a temperature of 600 to 700 DEG C, as a result of which there are obtained lead metal withdrawn from the process and a melt containing sodium sulphate, zinc and copper sulphides, and gangue. The melt is discharged from the reaction zone and subjected to a first leaching operation to obtain, as a result, a slurry representing a mixture of solid particles of sodium sulphate, zinc and copper sulphides, gangue and an aqueous solution containing essentially caustic soda. Further on, the slurry is filtered to produce a concentrated aqueous solution containing essentially caustic soda and a solid residue. The concentrated caustic soda solution is subjected to thickening by evaporation and the resulting caustic soda melt is fed into the reaction zone. The solid residue is subjected to a second leaching operation to obtain a suspension which is filtered to ultimately produce a cake representing solid particles of zinc and lead sulphides, and gangue having, adsorbed on their surface, a sodium sulphate solution, and an aqueous solution containing essentially sodium sulphate. Said solution is subjected to electrochemical treatment to obtain sulphuric acid withdrawn from the process, and alkali which is fed to said first leaching operation. The cake is washed to obtain a sodium sulphate solution which is fed to said second leaching operation.