Platinum refining method

Abstract

The invention discloses a platinum refining method. The method comprises the following steps: adding water to crude ammonium chloroplatinate, slurrying the crude ammonium chloroplatinate and water toobtain a slurry, heating the slurry to 90-95 DEG C, and adding sodium sulfite or sodium pyrosulfite while stirring until the crude ammonium chloroplatinate is completely dissolved; cooling the obtained solution, filtering the cooled solution, heating the obtained filtrate to 90-95 DEG C, adding hydrochloric acid and sodium chlorate with stirring, and stopping the addition of the hydrochloric acidand sodium chlorate when no ammonium chloroplatinate crystals are precipitated from the solution; cooling the obtained solution to room temperature, adding ammonium chloride, performing stirring to dissolve the ammonium chloride, and filtering the obtained solution to obtain a solid that is pure ammonium chloroplatinate; washing the obtained pure ammonium chloroplatinate with a hydrochloric acid and ammonium chloride mixed solution; and repeating above steps to obtain pure ammonium chloroplatinate, and finally carrying out high-temperature calcination on the pure ammonium chloroplatinate to obtain spongy platinum. The method avoids ammonium chloroplatinate calcination, aqua regia dissolution and the like, overcomes excessive palladium in the spongy platinum and other problems caused by insufficient nitrate removal of the platinum in the sponge platinum, and obtains the spongy platinum with a purity reaching up to 99.99%.

Description

technical field [0001] The invention relates to the technical field of heavy metal refining process in the metallurgical industry, in particular to a platinum refining process method. Background technique [0002] Platinum is a silver-white shiny metal with a melting point of 1772°C, a boiling point of 3827±100°C, and a density of 21.45g / cm at 20°C. 3 , relatively soft, has good ductility, thermal conductivity and electrical conductivity. Platinum sponge is a gray spongy substance with a large specific surface area and a strong ability to absorb gases (especially hydrogen, oxygen and carbon monoxide). Powdered platinum black can absorb a large amount of hydrogen. Platinum is chemically inactive and stable in air and humid environments. When heated below 450°C, a platinum dioxide film is formed on the surface, and can react with sulfur, phosphorus, and halogens at high temperatures. Platinum is insoluble in hydrochloric acid, sulfuric acid, nitric acid, and Alkaline solutio...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is exactly to provide a kind of platinum refining process for the above-mentioned problems existing in the technical process of refining platinum at present, the present invention adopts sodium sulfite or sodium pyrosulfite to reduce and dissolve crude ammonium chloroplatinate, avoiding the use of ammonium chloroplatinate calcining, Operations such as dissolving aqua regia have overcome a series of problems such as excessive palladium in sponge platinum caused by incomplete nitrate removal, and the invention can obtain sponge platinum with a purity higher than 99.99%.