How is rhodium gold refined? What is the rhodium refining process like?

How is rhodium gold refined? What is the rhodium refining process like?

Rhodium and gold refining is a process of refining rhodium and gold from platinum group metal scrap. Rhodium and gold are precious metals, and they are widely used in electronics, chemicals, pharmaceuticals and other fields. The following is the general rhodium and gold refining process.
Raw material treatment: The scrap is treated to remove impurities and get the scrap containing rhodium and gold.
Melting treatment: The scrap containing rhodium gold and oxidizer are mixed and melted at high temperature to oxidize and remove impurities such as iron, copper and lead from the scrap.
Dissolution treatment: The molten waste is dissolved in hydrochloric acid or ammonium chloride solution, so that rhodium and gold are transformed into metal ions in solution.
Extraction separation: Separation using organic extractants to separate rhodium and gold from other metal ions.
Removal of impurities: Use chemical methods to remove iron, copper, lead and other impurities from the extracted solution.
Precipitation reduction: reduce the rhodium and gold in the solution by reducing agent, so that they are precipitated in metal form.
Refining and purification: The precipitated rhodium and gold alloy will be refined and purified to get high purity rhodium and gold.
It should be noted that the refining process of rhodium and gold requires strict operating conditions and technical requirements to ensure the extraction efficiency and product quality.
The refining of rhodium is carried out in solution, and the crude metal rhodium must be dissolved first, by melting sodium bisulfate - dilute sulfuric acid leaching, medium temperature chlorination roasting - dilute hydrochloric acid leaching, pretreatment activation - aqua regia dissolution, electrochemical dissolution, etc., to obtain the H3RhCl6 solution without chaos. All the above dissolution methods need high temperature equipment, complicated operation process, long period, sometimes need to repeat several times to dissolve completely.
Preparation of pure chlororhodium acid (salt): Preparation of higher purity chlororhodium acid or its salt compounds is the basic step of rhodium refining. There are mainly methods such as sodium sulfite with, ammonia with, ammonium sulfite with, extraction and ion exchange, etc. Sometimes it is necessary to use a variety of methods together.
Preparation of pure rhodium chloride (salt): Preparation of rhodium chloride or its salts with high purity is the basic step of rhodium refining. There are mainly methods such as sodium sulfite with, ammonia with, ammonium sulfite with, extraction and ion exchange, etc. Sometimes a variety of methods need to be used in combination.