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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