Sponge rhodium powder and preparation method thereof

Abstract

The invention provides sponge rhodium powder and a preparation method thereof. The preparation method comprises the following steps: step a, preparing an alkali solution: adding alkali and an organic dispersant into water, stirring until the alkali and the organic dispersant are completely dissolved, heating the solution to 60-90 DEG C, and carrying out steam condensation reflux to obtain the alkali solution; step b, simultaneously dripping a reducing agent and a rhodium halide solution into the alkali solution by adopting a peristaltic pump to obtain a mixed solution, continuously monitoring the pH value of a mixed solution in the dripping process to ensure that the pH value of the mixed solution is greater than or equal to 10, and after the dripping of the reducing agent and the rhodium halide solution is completed, continuously reacting the mixed solution for 2 hours to obtain rhodium powder slurry; and c, filtering the rhodium powder slurry prepared in the step b, washing with pure water, and carrying out vacuum drying at 35-45 DEG C to obtain the sponge rhodium powder. The method is simple in preparation, low in energy consumption and high in operability, and the prepared sponge rhodium powder is small in granularity and easy to dissolve by adopting a chemical method.

Description

technical field [0001] The invention belongs to the technical field of precious metal preparation, in particular to a rhodium sponge powder and a preparation method thereof. Background technique [0002] Rhodium is widely used in industrial catalysts such as automobile exhaust catalysts, pharmaceutical catalysts, and petrochemical catalysts. During processing, rhodium must first be dissolved and converted into basic compounds of rhodium, and then further processed into rhodium nitrate solution, the precursor of automobile exhaust catalysts, Methanol carbonylation of rhodium iodide and chiral hydrogenation of rhodium homogeneous catalysts, etc. So rhodium dissolution technology is very important. [0003] The current rhodium powder dissolution technology mainly includes: chemical solution, Microwave dissolution method, ③high temperature melting method, ④electrochemical dissolution method. Among them, the chemical dissolution method has high requirements on the physical ...

AI Technical Summary

Problems solved by technology

The microwave dissolution method has high requirements on equipment, and must be dissolved in a microwave reactor under high temperature and high pressure conditions. The amount of batch dissolution is small, and it cannot meet the requirements of industrialization at present. It is only used in laboratory analysis and testing.

The high-temperature smelting method is to mix rhodium powder and potassium chloride, and react with chlorine gas under high temperature conditions. This is an industrialized process at present. It has the advantages of maturity and simple process, but it consumes a lot of energy and uses highly toxic chemicals during the reaction process. chlorine gas, and the reaction temperature needs to reach 550°C, which has certain risks

The reaction process of the electrochemical dissolution method is mild, but the energy consumption is too high, and the reaction process is very slow, which cannot meet the requirements of industrialization

These methods all have high requirements on the particle size of rhodium powder. Too large particle size will easily lead to slow reaction, and some even do not react.

At present, the production quality of precious metal rhodium powder and sponge rhodium powder in the domestic market is poor, the particle size is large and uneven, and it is easy to cause problems such as insoluble