Hunan ShenYe platinum and rhodium refining project

1, Basic principle.
After the dissolution of NaClO3 oxidation, add ammonium chloride to sink platinum, filter the sunken platinum residue after roasting to get crude platinum, crude platinum after chlorination and oxalic acid in addition to gold, add ammonium chloride to sink platinum again, in roasting to get crude platinum, repeat the operation several times, until you get a more pure platinum powder (cement-like).

2, reaction equation
3Pt+2NaClO3+18HCl=3H2PtCl6+2NaCl+6H2O,
H2PtCl6+2NH4Cl=(NH4)2PtCl6↓+2 HCl
2HAuCl4+3H2C2O4=2Au↓+6CO2↑+8HCl
(NH4)2PtCl6== (heating)==3Pt+2NH4Cl+16 HCl+2N2↑

3, production process and process conditions
1. Leaching
Platinum chloride leaching is under the action of strong oxidizing agents such as aqua regia, NaClO3, at a certain temperature and acidity conditions, so that all base metals and precious metals are oxidized and dissolved into the solution, silver is generated silver chloride precipitation in the slag, when the chloride slag is completely precipitated, filtered, the filter residue washed with 3N hydrochloric acid colorless.
2. Neutralization
The acidity of the leachate is high, adjust the pH=1 by adding NaOH, then filter and wash the slag with pH=1 hydrochloric acid until colorless.
3. Precipitation of platinum
At a certain temperature, add ammonium chloride to the neutralized and filtered liquid until the addition of ammonium chloride does not generate yellow precipitate, stop adding ammonium chloride, cool the liquid sharply to room temperature, let it stand and clarify, filter, and wash the filter residue with 10% ammonium chloride at room temperature 2-3 times.
4. Roasting
Put the filtered ammonium wave acid into the muffle furnace for roasting, ammonium chloroplatinate by high temperature decomposition for light gray sponge platinum, remove the sponge platinum, grinding again by chlorination, neutralization, oxalic acid in addition to gold, ammonium chloride sink platinum, and then roasting, repeated several times until you get a more pure platinum powder.