Process of regenerating and recovering lead sulphate-containing wastes
First Claim
1. A process of regenerating and recovering lead from lead battery scrap which comprises(i) contacting the lead battery scrap with an aqueous solution of ammonium carbonate to form lead carbonate and ammonium sulphate,(ii) subjecting the solid phase containing the lead carbonate obtained by solid-liquid separation of the reaction product so formed to roast-reduction at a temperature ranging from about 350°
- C. to about 700°
C. in the presence of a carbon material reducing agent to generate and recover the lead,(iii) double decomposing the liquid phase containing the ammonium sulphate obtained by said solid-liquid separation by the addition of calcium hydroxide in an amount such that the molar ratio of the calcium hydroxide added, expressed as Ca(OH)2 /(NH4)2 SO4 is about 1.05 to about 1.90 and that the concentration of a calcium sulfate slurry formed as by-product is about 5 to about 10%, and further contacting ammonium hydroxide thus formed with carbon dioxide gas, to recover ammonium carbonate in a form of an aqueous solution for reuse in said contacting step (i), and(iv) recycling the aqueous ammonium carbonate solution to step (i).
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Abstract
A process of regenerating and recovering lead from lead sulphate-containing wastes which comprises
(i) contacting the lead battery scrap with an aqueous solution of ammonium carbonate to form lead carbonate and ammonium sulphate,
(ii) subjecting the solid phase containing the lead carbonate obtained by solid-liquid separation of the reaction product so formed to roast-reduction at a temperature ranging from about 350° C. to about 700° C. in the presence of a carbon material reducing agent to generate and recover the lead,
(iii) double decomposing the liquid phase containing the ammonium sulphate obtained by said solid-liquid separation by the addition of calcium hydroxide in an amount such that the molar ratio of the calcium hydroxide added, expressed as Ca(OH)2 /(NH4)2 SO4, is about 1.05 to about 1.90 and that the concentration of a calcium sulfate slurry formed as a by-product is about 5 to about 10%, and further contacting ammonium hydroxide thus formed with carbon dioxide gas, to recover ammonium carbonate in a form of an aqueous solution for reuse in said contacting step (i), and
(iv) recycling the aqueous ammonium carbonate solution of step (iii) to step (i).
19 Citations
6 Claims
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1. A process of regenerating and recovering lead from lead battery scrap which comprises
(i) contacting the lead battery scrap with an aqueous solution of ammonium carbonate to form lead carbonate and ammonium sulphate, (ii) subjecting the solid phase containing the lead carbonate obtained by solid-liquid separation of the reaction product so formed to roast-reduction at a temperature ranging from about 350° - C. to about 700°
C. in the presence of a carbon material reducing agent to generate and recover the lead,(iii) double decomposing the liquid phase containing the ammonium sulphate obtained by said solid-liquid separation by the addition of calcium hydroxide in an amount such that the molar ratio of the calcium hydroxide added, expressed as Ca(OH)2 /(NH4)2 SO4 is about 1.05 to about 1.90 and that the concentration of a calcium sulfate slurry formed as by-product is about 5 to about 10%, and further contacting ammonium hydroxide thus formed with carbon dioxide gas, to recover ammonium carbonate in a form of an aqueous solution for reuse in said contacting step (i), and (iv) recycling the aqueous ammonium carbonate solution to step (i). - View Dependent Claims (2, 3, 4, 5)
- C. to about 700°
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6. A process of regenerating and recovering lead from lead battery scrap which consists essentially of
(i) contacting the lead battery scrap with an aqueous solution of ammonium carbonate to form lead carbonate and ammonium sulphate, (ii) subjecting the solid phase containing the lead carbonate obtained by solid-liquid separation of the reaction product so formed to roast-reduction at a temperature ranging from about 350° - C. to about 700°
C. in the presence of a carbon material reducing agent to generate and recover the lead,(iii) double decomposing the liquid phase containing the ammonium sulphate obtained by said solid-liquid separation by the addition of calcium hydroxide in an amount such that the molar ratio of the calcium hydroxide added, expressed as Ca(OH)2 /(NH4)2 SO4 is about 1.04 to about 1.90 and that the concentration of a calcium sulfate slurry formed as a by-product is about 5 to about 10%, and further contacting ammonium hydroxide thus formed, with carbon dioxide gas, to recover ammonium carbonate in a form of an aqueous solution for reuse in said contacting step (i), and (iv) recycling the aqueous ammonium carbonate solution of step (iii) to the step (i).
- C. to about 700°
Specification
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- Resources
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Current AssigneeDiamond Engineering Private Limited
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Original AssigneeDiamond Engineering Private Limited
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InventorsOkuda, Masaaki, Tomisaki, Kiyotaka
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Primary Examiner(s)Ozaki, G.
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Application NumberUS05/971,827Time in Patent Office637 DaysField of Search75/120, 75/77, 75/115, 423/92, 423/104US Class Current75/432CPC Class CodesC22B 13/045 Recovery from waste materialsY02P 10/20 RecyclingY02W 30/84 Recycling of batteries or f...
