Machine centrifugal extraction solvent extraction from the extraction of palladium in acidic solution
The platinum group metal refining traditional way is to have a series of precipitation -
Dissolving process, and low recovery efficiency, long production cycle, high cost, is not conducive to continuous production.
Therefore, there is a growing concern to adopt new technology to replace the traditional precipitation.
Solvent extraction technology because of large quantity, convenient operation, good separation effect, high recovery rate, high product purity, low cost, easy to realize automation advantages and more and more get people's attention.
Extraction of palladium, tianyi extraction to do a lot of research, and has made certain progress.
as you can see a large number of literature reports, for aqueous leaching palladium, from acid extraction of palladium chloride medium, there are also some extraction of palladium from nitric acid and sulfuric acid medium.
From organic light, the extracting agent including neutral, acid, alkali and chelating extraction agent, etc.
1, neutral extraction agent: neutral extraction agent such as sulfoxide, sulfide, alkyl oxide phosphorus, phosphate, etc. , they generally in the water is neutral, occupies an important position in the extraction and separation of precious metals.
sulfoxide divided into synthetic sulfoxide and petroleum sulfoxide, is a new type of neutral 60 s extractant, gaining industrial application in the 70 s, has wide sources, small toxicity, stable performance, etc.
Compared with sulfoxide, sulfur ether extraction ability, selective, but its extraction kinetics is slow.
2, acid extraction agent, mainly including carboxylic acid and acid phosphorus, sulfur, such as extracting agent.
In general acidic aqueous solution.
3, amine extraction agent, including primary amine, secondary amine and tertiary amine and quaternary ammonium salt and amide.
4, chelating extraction agent: refers to metal generated claw ring extraction compound extraction agent, including the beta
Two ketones, 8 -
Hydroxyquinoline, oxime, etc. , its extraction ability, good selectivity, and separation factor is big, is effective for palladium � � agent.
5, synergistic extraction agent: refers to a system containing two or more metal extraction solvent extraction, can produce synergistic extraction effect of extracting agent.
for neutral extractant, sulfoxide and corresponding sulfide ratio, its antioxidant capacity is strong, fast extraction, high capacity, no smell, wide application range.
Synthetic sulfoxide composed of a single, stable performance, but is expensive;
Petroleum sulfoxide cheap, but the composition complex, at present both in industrial test stage.
Compared with sulfoxide, sulfur ether extraction ability, good selectivity, and the common non-ferrous metals and other platinum group metals in general are not under the condition of extraction.
acid extraction agent and low price, but due to its high water solubility, so extraction solvent loss serious during extraction, and selective is bad, produce, platinum and palladium extraction.
amine extractant for palladium extraction ability, good selectivity, fast extraction.
But for primary, secondary, tertiary amine salt extractant, reverse extraction difficulty is the Achilles' heel, even with very high concentrations of hydrochloric acid is difficult to reverse extraction.
chelating extraction agent distribution ratio and selectivity of palladium is high, but the price is more expensive.
Due to the slow dynamics, phase equilibrium for a long time, when extraction need to add three octyl amine such as accelerating agent;
To adapt to the acidity range is narrow, only appropriate in weak acid solution for extraction;
From the organic phase, and the extraction of palladium are difficult from palladium extraction liquid was prepared with a long cycle of pure metal, unfavorable and production of high pure palladium.
for synergistic extraction agent, quaternary ammonium salt and sulfide, hydroxyl oxime and acid extraction agent can act as phase transfer catalyst, to speed up the extraction of palladium reaction rate, but also increased the extraction cost.
days use. cwl - extraction
M type centrifugal extraction machine solvent extraction from the extraction of palladium in the acid solution.