Method for concentrating metals from scrap containing metal

Abstract

The invention relates to a method for concentrating metals, in particular silver and/or tin and/or lead from scrap containing metal, by treating the material/scrap containing silver and/or tin and/or lead with a sulfonic acid of the formula RSO.sub.2OH in the presence of an oxidizing agent, wherein R can be an organic group or ammonia.

Claims

1. A method for the concentration of silver from silver-containing waste, comprising the steps that silver-containing waste is treated with a sulfonic acid of a formula RSO.sub.2OH in the presence of an oxidizing agent, wherein R is an organic group, to form a silver sulfonate solution, wherein a stoichiometric quantity of HCl is added to the silver sulfonate solution to precipitate silver as silver chloride and at the same time to reform sulfonic acid, and wherein treatment of the silver-containing waste takes place with at least 15% sulfonic acid that is 1/10 by mass of a 30% hydrogen peroxide solution, calculated on 50% sulfonic acid, which leads to the formation of the silver sulfonate.

2. A method according to claim 1, characterized in that the organic group is CH.sub.3 or NH.sub.2.

3. A method according to claim 2, characterized in that 15% to 50% by mass of methane sulfonic acid is used as sulfonic acid.

4. A method according to claim 1, characterized in that treatment occurs at ambient temperature.

5. A method according to claim 4, characterized in that the treatment time is reduced by increasing the temperature in comparison with the ambient temperature and/or an increase in the oxidizing agent concentration.

6. A method according to claim 1, characterized in that the method is operated continuously by continuous regeneration of the sulfonic acid.

7. A method for the concentration of silver from metal-containing waste, comprising the step that silver-containing waste is treated with a sulfonic acid of a formula RSO.sub.2OH in the presence of an oxidizing agent, wherein R is an organic group, and further, treatment of this silver-containing waste with at least 15% sulfonic acid that is 1/10 by mass of a 30% hydrogen peroxide solution, calculated on 50% sulfonic acid, leads to the formation of silver sulfonate.

8. A method for the concentration of silver from metal-containing waste, comprising the steps that silver-containing waste is treated with a mixture of sulfonic acid of a formula RSO.sub.2OH in the presence of an oxidizing agent, wherein R is an organic group, to form a silver sulfonate solution and a stoichiometric quantity of HCl is added to the silver sulfonate solution to precipitate silver as silver chloride and at the same time to reform sulfonic acid, such that the silver-containing waste is treated by a hydrometallurgical method, the mixture of sulfonic acid comprises hydrogen peroxide (H.sub.2O.sub.2) and methane sulfonic acid (CH.sub.3SO.sub.2OH or CH.sub.4SO.sub.3), the silver is dissolved from the silver-containing waste, and the silver is selectively precipitated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained below in closer detail by reference to a drawing and embodiments.

(2) FIG. 1 shows a diagram on the basis of the example for the system of silver-containing waste/methane sulfonic acid/hydrogen peroxide how a continuous extraction and thus concentration of the metal (silver in this case) is carried out.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(3) The principal sequence according to FIG. 1 on the basis of the example silver and methane sulfonic acid is the following:

(4) Silver-containing waste 1.1 in the form of Ag/matrix is treated with a mixture of hydrogen peroxide 2 (H.sub.2O.sub.2) and methane sulfonic acid 3 (HOSO.sub.2CH.sub.3 or CH.sub.4SO.sub.3). Silver mesylate 4 (AgOSO.sub.2CH.sub.3) is obtained at first which is highly soluble. The silver was thus removed from the silver-containing waste 1.1, so that the demetallised waste 1 can be disposed of or recycled in another manner. The silver content of the obtained solution can be determined analytically, so that the low-soluble silver chloride 6 (AgCl) can be precipitated subsequently with the stoichiometric quantity of hydrogen chloride (HCl). In this process, the hydrogen ion of HCl is exchanged for the silver, so that in the end methane sulfonic acid (HOSO.sub.2CH.sub.3) is formed back again.

(5) A number of specific embodiments are explained below:

Embodiment 1

(6) A mixture of 100 g of 50% methane sulfonic acid (CH.sub.4O.sub.3S) and 10 g of 30% hydrogen peroxide (H.sub.2O.sub.2) were added to 100.39 g of used silver-containing catalyst material (waste material). The originally dark colour of the catalyst material disappeared immediately and the white base body of the waste material of aluminium oxide became visible. The solution was filtered out and analysed. The silver content was determined at 35 g/L. 0.626 g of 32% hydrochloric acid (HCl) were added to 78.08 g of this solution, wherein the silver (Ag) was precipitated immediately as low-soluble silver chloride (AgCl). It was filtered out, washed and dried. The silver chloride thus obtained had a mass of 2.68 g. The filtrate contained the reclaimed methane sulfonic acid CH.sub.4O.sub.3S.

Embodiment 2

(7) 13.89 g of silicon cell rupture material, on which only the silver-containing contacts were present, were coated with a mixture of 20 g of 50% methane sulfonic acid and 2 g of 30% hydrogen peroxide. The silver strands on the silicon platelets dissolved rapidly, wherein the solution became slightly grey and turbid, which was caused by the insoluble components of the silver pastes. This solution was filtered and analysed. The silver content was 8.1 g/L. After the addition of 170 mg of 32% hydrochloric acid, the precipitated silver chloride was washed, dried and weighed. The yield was 0.21 g.

Embodiment 3

(8) 5 g of silver powder were covered with 13.5 g of a 25% amidosulfonic acid solution (NH.sub.2SO.sub.2OH). For this purpose, 10 drops of a 35% hydrogen peroxide solution were added slowly. After the complete dissolution of the silver, 12 g of a 31% solution were added to the clear solution and the obtained white precipitation of silver chloride was filtered out. Yield: 6.6 g of AgCl.

Embodiment 4

(9) 20 g of waste, consisting of flexible thin-film photovoltaic cells, were cut and a total of 500 mL of a 40% methane sulfonic acid solution were added thereto. 40 mL of a 50% hydrogen peroxide solution were added under stirring and filtering was performed after the dissolution of the photoactive connecting semiconductor layer and the silver contacts and the solution was analysed: 2000 mg/L of Ag, 2000 mg/L of Se, 400 mg/L of Cu, 750 mg/L of In and 120 mg/L of Ga. 1 g of a 33% HCl solution was dripped into this solution, wherein a white precipitation was produced immediately. It was filtered out and dried. Yield 1.3 g of AgC. No silver was found any more in the filtrate, but certainly the other metals.

(10) A method is provided with a solution in accordance with the invention with which it is possible to extract ecologically and economically valuable metals such as silver, lead, tin from respective metal-containing waste such as catalysts or waste from the photovoltaic industry and to make such metals available for further use.

LIST OF REFERENCE NUMERALS

(11) 1 Demetallised waste (matrix)

(12) 1.1 Silver-containing waste (Ag matrix)

(13) 2 Hydrogen peroxide (H2O2)

(14) 3 Methane sulfonic acid, the simplest organo-sulfonic acid (HOSO2CH3)

(15) 4 Silver mesylate, the simplest silver organo-sulfonate (AgOSO2CH3)

(16) 5 Hydrogen chloride (HCl)

(17) 6 Silver chloride (AgCl)