CS218293B1 - A method for obtaining molybdenum and copper from wastewater after producing phthalocyanine pigments - Google Patents

Abstract

The invention relates to a method for recovering molybdenum and copper from wastewater after the production of phthalocyanine pigments. Its essence lies in the fact that molybdenum is separated from wastewater by a solution of a high molecular weight amine in an organic, water-immiscible solvent, after which copper is separated by electrolysis. Molybdenum trapped in a solution of a high molecular weight amine can be separated into an aqueous solution by means of carbonates, or hydroxides of alkali metals, or ammonium.

Description

The invention relates to a process for recovering molybdenum and copper from wastewater after the production of phthalocyanine pigments.

So far, molybdenum, copper and other metals have been removed from the wastewater by precipitation with hydroxide or calcium carbonate, ion exchange, ion flotation of hydrophobic precipitates and electrolysis. However, these methods do not address the issue of obtaining individual metals.

This disadvantage is overcome by the process of recovering molybdenum and copper from wastewater after the production of the phthalocyanine pigments according to the invention. The process consists in extracting molybdenum from the waste water with a solution of a primary secondary or tertiary high molecular weight amine having a carbon number of 8 to 40, a molecular weight of 127 to 600, a concentration of 2 to 15% by weight in an organic water-immiscible solvent. the weight ratio of aqueous to organic phase is 10: 1 to 1: 10. The copper is then eliminated by electrolysis. The molybdenum trapped in the high molecular amine solution can be precipitated into the aqueous phase by means of carbonates or alkali metal hydroxides or ammonium at a concentration of 1 to 10% by weight at an aqueous to organic phase ratio of 10: 1 to 1:10.

An advantage of the process according to the invention is that it makes it possible to recover molybdenum and copper from waste water after the production of phthalocyanine pigments, which are very important metals for the national economy. Another advantage of the method is a relatively simple device for its implementation.

The process according to the invention is explained in more detail by way of examples.

Example 1

From the waste water containing 550 mg / l copper and 125 mg / l molybdenum, molybdenum was eliminated with a 0.1 mol / l solution of tri-n-octylamine in mineral benzene in a four-stage apparatus. Upon exclusion, the raffinate effluent contained 5 mg / l molybdenum and 545 mg / l copper. The organic phase was re-extracted with 10% ammonium hydroxide solution. During the reextraction in the two-stage apparatus, all molybdenum went into the aqueous phase. The regenerated organic phase was returned to the process. In the second phase, copper was removed from the wastewater by electrolysis on a rotating disc electrode.

Example 2

From the waste water with the same metal content as in Example 1, molybdenum was eliminated with a 0.1 mol / l solution of diononylamide in tetrachlorethylene in four extraction stages. After extraction, the raffinate effluent contained 6 mg / l molybdenum. Both the organic phase and the raffinate were further processed as in Example 1 with the same results.

Example 3

From the waste water with the same metal content as in Example 1, molybdenum was separated by a 0.1 mol / l solution of a mixture of primary amines having a carbon number of 17 to 24 in carbon tetrachloride in four extraction stages. The organic phase after extraction and the raffinate were further processed as in Example 1 with the same results.

Claims (3)

Process for recovering molybdenum and copper from wastewater after the production of phthalocyanine pigments, characterized in that molybdenum is extracted from the wastewater by a solution of a high molecular weight amine having a carbon number of 8 to 40, a molecular weight of 127 to 600, a concentration of 2 to 15% by weight. an organic solvent, wherein the weight ratio of the aqueous phase to the organic phase is 10: 1 to 1: 10, whereupon the copper is eliminated by electrolysis. 2. The process of claim 1 wherein the molybdenum retained in the high molecular amine solution is re-extracted with an aqueous solution of carbonates or alkali metal hydroxides or ammonium at a concentration of 1 to 10% by weight at an organic to aqueous phase ratio of 1:10 to 10: 1. . 3. The process of claim 1 wherein the high molecular weight amine organic phase is returned to the process after molybdenum reextraction.