CZ124698A3 - Process of re-doing ammonia alum to multipurpose fertilizer - Google Patents

Abstract

The method of processing aluminum-ammonium alum into a multi-purpose fertilizer consists in mixing aluminum-ammonium alum with ammonia or ammonia water or with magnesium carbonate or magnesium oxide in order to achieve a pH of the reaction mixture of 4 to 8.

Description

Method of processing of alum ammonium alum to multipurpose fertilizer

Technical field

The present invention relates to a process for the reprocessing of alum ammonium alumina resulting from, for example, the rehabilitation of a deposit contaminated with acidic saline solutions after the end of hydrochemical uranium mining.

BACKGROUND OF THE INVENTION

For the remediation of groundwater contaminated by chemical mining of uranium in the North Bohemian deposit, a procedure is considered which produces a significant amount of alum ammonium alum. The basic problem is to find an economically acceptable way of its use or disposal. The prior art processes for the processing of alum ammonium alum are directed to its thermal decomposition or ammoniacal decomposition directed at the effective separation of all its constituents, or alkaline decomposition by lime compounds in which ammonia is separated to form a storable mixture of gypsum and aluminum hydroxide. The use of alum for the production of aluminous cements or its consolidation is also monitored. The main disadvantages of the above mentioned procedures are high investment, operational and ecological demands of individual solutions.

SUMMARY OF THE INVENTION

To a large extent, the method of converting alum ammonium alum to a multipurpose fertilizer according to the present invention comprises treating the alum ammonium in dissolved or crystalline form with ammonia or magnesium oxide or magnesium carbonate or all of these components in a predetermined ratio and ordering the resulting pH of the reaction mixture to be 4-8. The result of this reaction is a multipurpose industrial fertilizer - ammonium sulphate or magnesium-ammonium sulphate with aluminum hydroxide, which has a positive effect on soil sorption properties. If preferred, the ammonium alum alum is treated with magnesium oxide so that the resulting pH of the mixture is above 8. The treatment of the ammonium alum under these conditions generates gaseous ammonia, which can advantageously be recycled into alum production technology and a mixed fertilizer composition magnesium sulfate and aluminum hydroxide. Said process can be carried out by treating ammonia or magnesium oxide or magnesium carbonate or all of these components in a predetermined ratio and order on the alum ammonium in dissolved or crystalline form or in the form of a suspension, where part of the alum is dissolved and part of the alum is in the form of crystals. After the neutralization reaction, free water is evaporated from the resulting mixture of aluminum hydroxide and ammonium sulphate or magnesium sulphate or magnesium sulphate, which are partially or predominantly dissolved, and the dissolved sulphates are converted to crystalline form.

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Examples of embodiments of the invention

Example. 1;

1000 kg of alum ammonium alum are mixed with ammonia gas and water at 60-100 ° C to achieve a pH of 4-8 in the reaction mixture. The dosing of water is governed by the mixing conditions of the resulting reaction mixture. The resulting aluminum hydroxide reaction mixture in ammonium sulfate solution was dried to a residual water content of less than 10%. Possible sinters of aluminum hydroxide and crystalline ammonium sulphate are crushed.

Example 2:

100 kg of alum ammonium alum are mixed with 135-160 kg of magnesium oxide and the temperature of the reaction mixture is adjusted (for example by preheating the alum) to 50-100 ° C. The resulting mixture was allowed to react and then cooled.

Example 3

1000 kg of crystalline alum ammonium alum are mixed with 450 - 470 kg of ammonia water with a concentration of 25% ammonia and the resulting mixture is dried so that the residual water content is less than 10%. Possible sinters of aluminum hydroxide and crystalline ammonium sulphate are crushed.

Industrial applicability

The invention can be used wherever problems arise with aluminum ammonium waste alum.

Claims (9)

PATENT CLAIMS Method for converting alum ammonium alum into a multipurpose fertilizer, characterized in that the alum ammonium in crystalline or dissolved form or in the form of a crystal and dissolved alum suspension is treated with ammonia, magnesium oxide or magnesium carbonate or these components in a preselected ratio and in order to achieve a pH of 4-8 in the reaction mixture, the resulting reaction mixture is dried to form a multipurpose industrial fertilizer containing aluminum hydroxide and ammonium sulfate or magnesium sulfate and / or magnesium ammonium sulfate. A process for converting alum ammonium alum into a multi-purpose fertilizer according to claim 1, wherein the alum ammonium alum comprises ferric and potassium alum as an admixture. Method for converting alum ammonium alum into a multi-purpose industrial fertilizer according to claim 1 or 2, characterized in that the alum is completely or partially dissolved in the crystal water itself by heating. A process for converting alum ammonium alum into a multi-purpose industrial fertilizer according to claim 1 or 2, characterized in that the alum is completely or partially dissolved by the addition of water. A process for processing alum ammonium alum into a multi-purpose industrial fertilizer according to claim 1 or 2, characterized in that the alum is completely or partially dissolved by a combination of water addition and heating. Method for converting alum ammonium alum into a multi-purpose industrial fertilizer according to claim 1 or 2, characterized in that the ammonia is used in the gaseous state or as ammonia water. 7. A process for processing alum ammonium alum into a multi-purpose industrial fertilizer according to claim 1 or 2, wherein ammonia and magnesium oxide are first treated with ammonia and then magnesium oxide in the case of simultaneous application of ammonia and magnesium oxide. A process for converting alum ammonium alum into a multipurpose industrial fertilizer according to claim 1 or 2, characterized in that in the case of simultaneous application of magnesium carbonate with ammonia or magnesium oxide to the fully or partially dissolved alum, magnesium carbonate is first applied and then ammonia or magnesium oxide. . A process for converting alum ammonium alum into a multi-purpose industrial fertilizer according to claim 1 or 2, characterized in that the pH of the reaction mixture is raised above 8 under the action of magnesium oxide and the ammonia released from the alum is recycled to the production technology thereof. • · · · · -410. The process of converting an ammonium alum to a multipurpose industrial fertilizer according to claims 1 or 2, characterized in that water is evaporated from the mixture resulting from the decomposition of aluminum ammonium alum containing aluminum hydroxide and dissolved ammonium or magnesium or magnesium or ammonium sulphates, and said sulphates crystallized.