SU424816A1 - METHOD FOR PROCESSING CHROMINE-CONTAINING SOLUTIONS - Google Patents

Description

one

This invention relates to a process for the treatment of chromium-containing solutions.

A known method of processing chromium-containing solutions, which are waste products of various organic industries, is that these solutions are treated at boiling point with sodium-containing reagents, which are alkaline solutions of sodium aluminate or sodium silicate or their mixture. The process is conducted to a pH of at least 6.0 to obtain mixed hydroxide compounds of chromium, aluminum and silicon.

In order to produce trisubstituted chromium phosphate, a method has been proposed for treating chromium-containing solutions by treating the latter with an alkaline solution of sodium orthophosphate in an amount of 100-105%, preferably 102%, of the processed solutions necessary for binding chromium to chromium phosphate. Proness lead to pGH 5.2-5.6 and at 95-98 ° C.

As chromium-containing solutions, waste from various organic industries is used, for example, citral, monomer 4,4-diaminodiphenylsulfone.

Example. 95 g of waste from the production of monomer 4,4-diaminodiphenylsulfone, containing 19.6% of trivalent chromium in terms of CGO3; 27.2% of sulfur compounds in terms of S04 and 6.2% of organic substances in terms of carbon are mixed with 300 ml of wash water from previous experience with a content of 26.1 g / l of phosphates in terms of

NzR04; 42.3 g / l sodium sulfate in terms of S04; 0.38 g / l CrO2 and 1.4 g / l C. The resulting mixture is heated to 98 ° C and then 125 ml of an alkaline solution of sodium phosphate, containing 26.7 g of Na3P04, are slowly poured.

and 10.3 g of NaOn. In total, about 102% of the phosphate of sodium required for chromium (P1) binding to chromium phosphate, which is theoretically necessary for the binding of chromium, is introduced.

The resulting reaction mass with a pH of about 5.3 is maintained at the temperature of the experiment for 0.5 hours, and then filtered on a filter funnel under vacuum. The average filtration rate was 1.31 ml / cm-min. For the purpose of sufficiently complete washing of the formed precipitate of middle chromium phosphate from sodium nitride compounds, washing is conducted with hot water acidified with phosphoric acid. The resulting washings are used in the following experiment.

The wet precipitate of chromium phosphate .iX 2О-P.J.) has the following composition: 14.1% CrO2; 12.9% RhoZ; 0.6% S04; 0.6% Na; 0.2% FeO and 0.06% organic matter in non-abstinence on carbon. 3 Subject of the invention. Method of processing chrome-containing plants. thieves by treating them with alkaline sodium-containing reagents followed by separating the precipitate formed and washing it from soluble impurities, characterized in that, in order to obtain three-part chromium phosphate, an alkaline solution of sodium orthophosphate in an amount of 100-105% is used , preferably 102%, of the processed solutions required for chromium binding to the average chromium phosphate and the process is carried out to a pH of 5.2-5.6 and at 95-98 ° C.