A process for separating and purifying sponge platinum from ammonium chloroplatinate

Abstract

The invention discloses a process for separating and purifying sponge platinum from materials containing ammonium chloroplatinate. The steps are: add water to slurry the crude ammonium chloroplatinate, add hydrochloric acid, raise the temperature to 90-95°C, and add sodium chlorate until the solid is completely dissolved. , heat up to 95-100°C to catch chlorine, cool and filter; after the filtrate is heated to 40-65°C, add ammonium chloride to precipitate platinum, and filter after cooling; repeat refining once, add NaOH to the secondary platinum solution for hydrolysis; The acidity of the hydrolysis filtrate is lowered, adding dimethylglyoxime to remove palladium; adding ammonium chloride to the filtrate, filtering to obtain pure ammonium chloroplatinate, reducing it with hydrazine hydrate to obtain high-purity platinum powder, and boiling it with nitric acid to obtain sponge platinum pink. The process of the present invention can stably produce sponge platinum meeting SM-99.99, and the process flow is simple, the raw material adaptability is strong, the recovery rate of platinum is high, and operations such as calcination of ammonium chloroplatinate and aqua regia dissolution are avoided, which overcomes the problem of nitrate catching Failure to completely cause a series of problems such as excessive palladium in platinum sponge.

Description

technical field [0001] The invention belongs to the field of separation and purification of platinum metal, and in particular relates to a process for separating and purifying 99.99% sponge platinum from ammonium chloroplatinate materials. Background technique [0002] Platinum sponge is a chemical substance, black powder, soluble in aqua regia; insoluble in water and inorganic acids. Density: 5.78g / ml, melting point: 1769°C, boiling point: 3827°C, platinum sponge is mainly used to make catalysts. There are many platinum refining processes, and the main methods currently used in production are: aqua regia dissolution-ammonium chloride repeated precipitation method, oxidation hydrolysis method, carrier hydrolysis method, carrier hydrolysis-ion exchange method, alkali dissolution-reduction method, reduction- Dissolution method, reduction dissolution-ammonium chloride repeated precipitation method and extraction and refining method, etc. Based on the aqua regia dissolution-am...

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Problems solved by technology

[0004] The purpose of the present invention is exactly to aim at the above-mentioned problem existing in the technical process of refining platinum at present, a kind of platinum refining process method is provided, the present invention adopts acidic system sodium chlorate to oxidize and dissolve crude ammonium chloroplatinate, concentrates hydrolysis to remove impurity process, avoids Operations such as ammonium chloroplatinate calcining and aqua regia dissolving have overcome a series of problems such as insufficient palladium in sponge platinum caused by incomplete nitration, and the invention can obtain sponge platinum with a purity higher than 99.99%.

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