A method for efficiently separating and purifying palladium and rhodium from alloy flakes containing palladium and rhodium alloy

Abstract

The invention provides a method for efficient separation and purification of palladium and rhodium from an alloy sheet containing palladium-rhodium alloy. The method comprises the steps that the palladium-rhodium alloy sheet is dissolved with a nitromurlatic acid solution, then palladium is dissolved in the nitromurlatic acid solution, while rhodium resistant to corrosion from the nitromurlatic acid solution is not dissolved and deposits at the bottom of a container in the form of fine powder, so that palladium and rhodium are separated; potassium permanganate and ammonium chloride are added into the solution containing palladium, so that red palladium sediment is obtained to realize purification, and then a chemical reagent is added to generate dichlorodiamminepalladium which is used as araw material for synthesizing tetraamminepalladium sulfate; and the insoluble rhodium is roasted together with sodium peroxide and is then soaked in acid to be dissolved to obtain rhodium-containingliquor, and rhodium powder with the purity of 99.95% is obtained after purification and reduction.

Description

technical field [0001] The invention belongs to the field of metallurgy of platinum group metals, in particular to a method for efficiently separating and purifying palladium and rhodium from alloy flakes containing palladium and rhodium. Background technique [0002] Both palladium and rhodium metals belong to the platinum group metals and have many unique and superior physical and chemical properties. They have important special applications in the electronics industry, military industry and aerospace industry and cannot be replaced by other metals or materials. They have been honored as " "Modern industrial vitamin" and "the first high-tech metal", so it is of great significance to the recovery of platinum group metals. Due to their special physical and chemical properties, platinum and rhodium metals have strong corrosion resistance to acid and alkali, and it is difficult to dissolve them with a single acid or alkali, which also brings certain difficulties to their recyc...

AI Technical Summary

Problems solved by technology

Generally, the purification of palladium to 99.95% requires repeating steps ③→⑤2-3 times to achieve, resulting in a large amount of waste water; if the raw material contains many impurity elements, step ③ will generate a large amount of sediment, which is large in size, suspended or floating In the solution, it forms a paste, entrains palladium, and the filtration speed is slow when filtering. After filtration, a large amount of palladium remains in the filter residue. The distribution ratio of palladium in the filter residue to the filtrate is between 4:6-2:8. One-time separation and purification of palladium The effect is poor, and the filter residue needs to repeat steps ①-⑦ many times to reduce the palladium content in the residue to below 1%.

This method is currently the most common method used in the industry. It not only takes a long time, consumes a lot of acid-base reagents, but also has a large amount of wastewater and a low recovery rate.