RU2622072C1 - Method of utilisation of a processed copper-ammonium solution - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method involves treating the spent concentrated copper-ammonia solution with a solution of hydrochloric or sulfuric acid to a pH of 5.5-6.5 to separate the copper ions in the form of a precipitate of copper hydroxide. Then, the ammonium ion is isolated by introducing a solution of sodium hydroxide into the filtrate after separation of the copper hydroxide solution to pH 8.5-9.5, sodium hydrogen phosphate and chloride or magnesium sulfate to form a sparingly soluble magnesium ammonium phosphate compound. In this case, the treatment of the initial solution is carried out at a temperature of 10-25°C.

EFFECT: method allows a relatively small amount of reagents, once they are introduced, to return to production copper and produce the final product - a fertiliser containing ammonium nitrogen.

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Description

The present invention relates to methods for complex reagent processing of an spent solution containing ammonia and ammonia complexes of copper by sequential removal of copper and ammonium ions in the form of insoluble compounds. It can be used for the disposal of spent copper-ammonia solutions for etching printed circuit boards and a solution for the production of divinyl.

A common method of processing spent copper-ammonia solutions in order to extract copper is the electrochemical separation of the latter at the cathode [1].

The disadvantage of this method is the incomplete extraction of copper from the solution; the method is complex - it requires special hardware design, including cooling of the electrodes. The method is not reliable enough and requires special security measures. This method has a number of limitations associated with a significant release of chlorine at the insoluble anode, a significant consumption of electricity, which is due to the low cathode current output. The latter is associated with the chemical dissolution of copper released at the cathode by the reaction

Cu + Cu ²⁺ = 2Cu ⁺ .

This method does not provide for the utilization of ammonia.

The known method [2], which relates to the purification of spent alkaline copper plating solutions containing Trilon B or Rochelle salt as a ligand, which involves the reduction of copper (II) cations and the isolation of ethylene diamine tetraacetic acid or potassium hydrotartrate from an acid solution, respectively. Copper (II) cations are reduced by adding a monosaccharide to the alkaline solution when heated to form a copper (I) oxide precipitate, and after the separation of ethylenediaminetetraacetic acid or potassium hydrotartrate, the residual amounts of copper (II) are reduced by carburizing on iron in an acidic medium. The resulting copper oxide (I), ethylenediaminetetraacetic acid or potassium hydrotartrate regenerate. The method allows to isolate from the spent solutions complexons and copper cations for their use in the preparation of galvanic solutions and to treat waste water.

The disadvantage of this method is the use of a rather expensive monosaccharide, as well as the final removal of copper by cementation on iron waste, which leads to its irretrievable losses.

A known method of processing copper-ammonia solutions, including processing the solution with hydrochloric acid, the deposition of copper in the form of a precipitate - sparingly soluble compounds [3]. The precipitate is treated with a solution of Rochelle salt and sodium hydroxide. The disadvantage of this method is the rather slow filtering rate of the precipitate and its complex composition, which complicates its disposal, in particular, the isolation of copper in it in its pure form. The method does not allow to utilize ammonia, which is present in the solution.

A known method of processing copper-ammonia solutions, including processing solutions with a reagent (polyethylene oxide), heating the solutions, blowing off ammonia, isolating (filtering) the precipitate of copper hydroxide formed [4]. The disadvantage of this method is the insufficient completeness of the separation of copper from the solution, the difficulty of filtering the precipitate of copper hydroxide, and the need to use special reagents - polyethylene oxide, which complicates the method, and ammonia blowing leads to environmental pollution.

A known method [5] utilization of copper-ammonia solutions, including the processing of solutions with alkali to isolate copper in the form of a precipitate at a pH of 8-8.2. Copper oxide powder may be added to the solution to be treated to accelerate the formation of sediment. Then the solutions are heated to 75-90 ° C by sparging through solutions of water vapor or hot air and continue to be treated with alkali to a pH of 12.5-13.5 with stirring. The disadvantage of this method is the additional energy consumption for heating the solution, and sparging the solution with hot air or steam leads to environmental pollution by ammonia.

A known method of disposal of copper-ammonia solution [6], which consists in diluting it with water to a copper content of not more than 3 wt. % At the same time, fungicide is obtained for the prevention and treatment of leaf diseases of plants and foliar feeding of treated crops. The disadvantage of this method is the pollution of copper and ammonia in the environment and at the same time there are irretrievable losses of copper.

Removal of ammonia from the spent solution after removal of copper ions from the solution is supposed to be carried out by blowing it with air from the solution at a pH of more than 11 and subsequent absorption with water [7]. Using this method leads to the need to manufacture quite expensive equipment. At the same time, the possibility of ammonia entering the atmosphere not only of the working area, but also of nearby areas with residential buildings, is not ruled out.

Of the known closest in technical essence is the method [8] of regenerative purification of copper-ammonia etching solutions, which includes neutralizing the treated solution with hydrochloric acid or acidic copper plating, precipitating copper in the form of a sparingly soluble compound and separating the precipitate from the solution. The precipitate of a sparingly soluble copper compound is regenerated by dissolving in hydrochloric acid to obtain a copper chloride concentrate. Water is removed from the solution after separation of the copper precipitate, and in the presence of an organic solvent ammonium chloride is isolated, which can be used to prepare galvanic copper plating solutions. The organic solvent is regenerated by distillation, and the residual copper from the solution is removed by acidification with cementation by iron.

The disadvantage of this method is the incomplete extraction of copper from the solution, and the removal of copper by cementation on iron waste leads to its loss; the method is complicated - it requires special hardware design (distillation installation). The method is not reliable enough and requires the use of special safety measures, which is due to the use of an organic solvent.

The problem to which the claimed invention is directed, is to develop an effective, environmentally friendly and economically cheap method of disposal of the spent solution containing ammonia complexes of copper and ammonia, with the receipt of final products that can be used in other industries or constitute the final commercial product.

This is achieved by the fact that in this method, the disposal of the spent solution containing copper and ammonium ions is carried out in two stages. At the first stage, after diluting the solution with water (this is done for further rapid filtering of the precipitate) to a copper ion concentration of 5-10 g / l, copper is extracted from the solution by transferring it to a sparingly soluble compound - copper hydroxide.

At the second stage, ammonium ion is separated from the solution by transferring it to the precipitate in the form of a sparingly soluble compound of magnesium ammonium phosphate [9], which is formed by the addition of sodium phosphate and magnesium chloride or sulfate.

The method is as follows. First, prepare aqueous solutions of hydrochloric (10%) or sulfuric acid (5%), disubstituted sodium phosphate with a concentration of 5-10% and magnesium chloride or sulfate with a concentration of 5-10%.

Then, solutions of hydrochloric or sulfuric acid are introduced into a dilute solution containing copper and ammonium ions to a pH of 5.5-6.5. In this case, precipitation of copper (II) hydroxide occurs, and the solution above the precipitate becomes almost colorless and transparent. The formation of sediment occurs within 12-24 hours. Then, the solution over the precipitate is poured into the collection tank for further processing, and the precipitate is filtered through a “chlorine cloth” or in specialized filter units and dried. Dried sludge is handed over to the warehouse in plastic bags for further use in copper smelters.

In the second stage, after separation of the precipitate of copper hydroxide, solutions of disubstituted sodium phosphate and magnesium chloride or magnesium sulfate are introduced at a pH of 8.5-9.5 (supported by the introduction of sodium hydroxide solution). At the same time, within 12-24 hours, ammonium ion is released from the solution by transferring it to the precipitate in the form of a sparingly soluble compound magnesium ammonium phosphate, which is formed by the addition of salts in the indicated sequence. The completeness of the extraction of ammonium ion from the solution is checked by adding a solution of a salt of sodium hydrogen phosphate and magnesium chloride to a small volume of the filtered solution. If there is no precipitate, the addition of the above solutions is stopped.

Then the solution above the sludge is poured into the sewer to the treatment plant of the enterprise, and the remaining sludge is separated from the solution by filtration.

The content of copper ions in the filtrate after filtration does not exceed 0.05 mg / L, and ammonium nitrogen 1 mg / L. The processing of the solution is carried out at a temperature of 10-25 ° C.

The precipitate of magnesium ammonium phosphate can be used as fertilizer [10].

Table 1 shows the quality indicators of specially prepared and spent copper-ammonia solutions obtained from the Penza NLP Rubin OJSC and processed by the proposed method.

As can be seen from the table, in the prepared solutions and solutions taken from OAO NPP Rubin, before disposal, the concentration of copper ions is 5-10 g / l and ammonium nitrogen 50-120 g / l, and after the disposal process according to the proposed method, 0.035- 0.05 mg / L and 0.8-1.0 mg / L, respectively.

Thus, the data presented indicate a sufficiently high efficiency of the proposed method for the disposal of spent concentrated copper-ammonia solution. The proposed method is relatively simple and affordable.

Literature

1. Auth. St. No. 1407994, cl. C23G 1/36, 1986.

2. RF patent No. 2343225, cl. C23F 1/46 C23G 1/36.

3. Auth. St. No. 1303631, class C23G 1/36, 1986.

4. Auth. St. No. 1481209, class C02F 1/62, 1987.

5. RF patent 2016103 class. С22В 3/44 С22В 15.

6. RF patent No. 2131860, class. C05G 3/02 with A01N 59/20.

7. Pestrikov S.V., Zeldova A.I. Utilization of waste copper-ammonia solutions for etching printed circuit boards. - Ufa: State Unitary Enterprise RB “Ufa Printing Plant”, 2009. - 100 p.

8. RF patent №2334023, class. C22V C23G C25V

9. Kreshkov A.P. Fundamentals of analytical chemistry. Theoretical basis. Qualitative analysis. Ed. M .: Chemistry, 1965, Vol. 1. - 472 p.

10. Chemistry. Big Encyclopedic Dictionary / Ch. ed. I.L. Knunyants. - 2nd ed. - M: Big Russian Encyclopedia, 1998 .-- 792 p.

Claims (1)

The method of disposal of spent concentrated copper-ammonia solution, including its treatment at a temperature of 10-25 ° C with a solution of hydrochloric or sulfuric acid to a pH of 5.5-6.5 and the separation of copper ions in the form of a precipitate of copper hydroxide from the solution, characterized in that after separating the precipitate of copper hydroxide, sodium hydroxide is added to the solution to a pH of 8.5-9.5, sodium hydrogen phosphate and magnesium chloride or sulfate and provide the formation of a sparingly soluble compound of magnesium ammonium phosphate.