The present invention provides a method for the treatment of sludge containing iron and between 4.5% to 12% by weight of zinc. This method includes a leaching step wherein leaching agents include hydrochloric acid and chlorate, and wherein the pH of the leachate directly resulting from this leaching step is set at a value below 1.5. A recycling method and treatment installation are also provided.

The present invention provides a method for the treatment of sludge containing iron and between 4.5% to 12% by weight of zinc. This method includes a leaching step wherein leaching agents include hydrochloric acid and chlorate, and wherein the pH of the leachate directly resulting from this leaching step is set at a value below 1.5. A recycling method and treatment installation are also provided.

Any metal having a low α-ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an α-ray after heating the metal at 100° C. in an atmosphere for six hours is 0.002 cph/cm.sup.2 or less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an α-ray emission of 10 cph/cm.sup.2 or less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.

Any metal having a low α-ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an α-ray after heating the metal at 100° C. in an atmosphere for six hours is 0.002 cph/cm.sup.2 or less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an α-ray emission of 10 cph/cm.sup.2 or less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.

An agent for selective antimony and arsenic removal and tin retaining includes 10-30 wt % of aluminum, 65-85 wt % of calcium, 1-10 wt % of coke powder, and 1-5 wt % of lead powder. According to the content of antimony in lead, the antimony and arsenic removal and tin retaining agent is added to a molten lead which is at a temperature of about 550-650° C. at a certain proportion so as to carry out an antimony and arsenic removal reaction; after the reaction is completed, cooling is carried out, and antimony and arsenic scum is fished out to obtain a molten lead with antimony and arsenic removed; the content of antimony and arsenic is reduced to 0.0005 wt % or less, and the content of tin is substantially unchanged. The production costs for lead alloy preparation are reduced, and no smoke and odor appear in an antimony and arsenic removal reaction process.

An agent for selective antimony and arsenic removal and tin retaining includes 10-30 wt % of aluminum, 65-85 wt % of calcium, 1-10 wt % of coke powder, and 1-5 wt % of lead powder. According to the content of antimony in lead, the antimony and arsenic removal and tin retaining agent is added to a molten lead which is at a temperature of about 550-650° C. at a certain proportion so as to carry out an antimony and arsenic removal reaction; after the reaction is completed, cooling is carried out, and antimony and arsenic scum is fished out to obtain a molten lead with antimony and arsenic removed; the content of antimony and arsenic is reduced to 0.0005 wt % or less, and the content of tin is substantially unchanged. The production costs for lead alloy preparation are reduced, and no smoke and odor appear in an antimony and arsenic removal reaction process.

An agent for selective antimony and arsenic removal and tin retaining includes 10-30 wt % of aluminum, 65-85 wt % of calcium, 1-10 wt % of coke powder, and 1-5 wt % of lead powder. According to the content of antimony in lead, the antimony and arsenic removal and tin retaining agent is added to a molten lead which is at a temperature of about 550-650° C. at a certain proportion so as to carry out an antimony and arsenic removal reaction; after the reaction is completed, cooling is carried out, and antimony and arsenic scum is fished out to obtain a molten lead with antimony and arsenic removed; the content of antimony and arsenic is reduced to 0.0005 wt % or less, and the content of tin is substantially unchanged. The production costs for lead alloy preparation are reduced, and no smoke and odor appear in an antimony and arsenic removal reaction process.

An agent for selective antimony and arsenic removal and tin retaining includes 10-30 wt % of aluminum, 65-85 wt % of calcium, 1-10 wt % of coke powder, and 1-5 wt % of lead powder. According to the content of antimony in lead, the antimony and arsenic removal and tin retaining agent is added to a molten lead which is at a temperature of about 550-650° C. at a certain proportion so as to carry out an antimony and arsenic removal reaction; after the reaction is completed, cooling is carried out, and antimony and arsenic scum is fished out to obtain a molten lead with antimony and arsenic removed; the content of antimony and arsenic is reduced to 0.0005 wt % or less, and the content of tin is substantially unchanged. The production costs for lead alloy preparation are reduced, and no smoke and odor appear in an antimony and arsenic removal reaction process.

Any metal having a low -ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an -ray after heating the metal at 100 C. in an atmosphere for six hours is 0.002 cph/cm.sup.2 or less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an a-ray emission of 10 cph/cm.sup.2 or less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.

Any metal having a low -ray emission, the metal being any one of tin, silver, copper, zinc, or indium, wherein an emission of an -ray after heating the metal at 100 C. in an atmosphere for six hours is 0.002 cph/cm.sup.2 or less. Any metal of tin, silver, copper, zinc and indium each including lead as an impurity is dissolved to prepare a hydrosulfate aqueous solution of the metal and lead sulfate is precipitated and removed in the solution. The lead sulfate is precipitated in the hydrosulfate aqueous solution by adding a lead nitrate aqueous solution including lead having an a-ray emission of 10 cph/cm.sup.2 or less to the hydrosulfate aqueous solution, from which the lead sulfate has been removed, and, at the same time, the solution is circulated while removing the lead sulfate to electrowinning the metal using the hydrosulfate aqueous solution as an electrolytic solution.