Solvent extraction can be used as an important technique to improve the efficiency of traditional smelting process in addition to impurities or as an intermediate product of high purity extraction technology. To improve the purity of nickel, the key is how to remove one of the most difficult impurities to separate-cobalt. In this sense alone, solvent extraction is also the extraction of high purityNickelAn important technology. Although solvent extraction can be fromNickelIn the salt aqueous solution, the impurity drill is given priority and effective removal, but there are not many kinds of extracts that can be used in industry.
pc-88a and CYANEX-272 Two medicaments can be used as practical extracts when removing the drill with impurity morphology coexisting in nickel sulfate aqueous solution by solvent extraction. No matter which extraction agent is diluted with organic solvent into the appropriate concentration of the solution as an organic phase, so that it is mixed with the raw material nickel sulfate solution (water phase). The impurity drilling ions in the water phase are extracted and removed into the organic phase by generating complexes with the extraction agent of the organic phase.
For example, extraction under the condition of ph5-6, it is difficult to separate the removed drill ions can easily be extracted into the organic phase, while nickel ions remain in the water phase. It can also be shown that if Fe, Zn, Al, Cu, Mn, Mg and CA plasma also coexist in impurity form at this time, they can be extracted and removed together with the drill. In this way, solvent extraction is an excellent refining method to remove all kinds of impurities together at the same time.
Nickel chloride isNickelAnother important salt in the intermediate product. Using the third stage amine as extractant solvent extraction to remove the impurity cobalt co-produced in nickel chloride, the mechanism of extracting the drilling in nickel chloride solution with the third stage amine is cobalt chloride anion and the third stage amines diluted to the appropriate concentration in the organic solvent to produce ion pairs.
For example, a drill that coexists in the form of impurities in a nickel chloride solution with a chloride ion concentration of 280-300g/l can be extracted as a priority for removal into the organic phase, while nickel remains in the water phase. And, if there are Zn, Fe, Cu, MN and other impurities co-exist, it can also be extracted and removed together with the drill.
In this way, if solvent extraction technology is used, the drilling in nickel sulfate or nickel chloride solution can be extracted and removed in all the same time, and high purity nickel higher than the existing purity is obtained by electrolytic reduction from the refined nickel acid or nickel chloride solution.
According to the above analysis, the electrolytic nickel obtained from the traditional smelting process and the nickel chloride aqueous solution are used as anodes and electrolytes respectively, while the third stage amine is the extraction agent in the net liquid of the electrolyte, if only from the metal composition, electrolytic nickel after refining can be more easily obtained impurity content from 10-20ppm 4 9 grade nickel. But if gas impurities are taken into account, it is difficult to guarantee 4 9 grades.
In the case of hydrogen dissolution, for example, nickel metal does not dissolve at high concentrations after the formation of hydride, but is much larger than the solubility of metal iron and metal diamonds, and the concentration of hydrogen in electrolytic nickel is generally dozens of ppm. In addition, electrolytic nickel usually contains dozens of-hundreds of ppm of oxygen, containing dozens of ppm of nitrogen. Therefore, to obtain a higher purity metal nickel, these gas components must be removed. For this reason, the gas is usually removed by vacuum melting approximations, but oxygen removal is difficult and the residual oxygen is about. In this regard, the concentration of oxygen, nitrogen and hydrogen can be reduced to a few ppm if heat treatment is added to hydrogen before melting nickel, followed by vacuum melting to free gas.
The purity of nickel metal obtained by traditional nickel smelting method is in. Above, it is refined by electrolysis, which includes solvent extraction of net liquid, and then vacuum melting after hydrogen treatment to release the gas, it becomes the above metal nickel.
In order to make metal nickel of higher purity, the use of regional refining methods may be considered. such as as an analysis of the standard and available metal nickel has been refined in the region, but despite this, the grade is generally only 99.995%.
To obtain a higher purity metal nickel, several different refining methods are combined to remove impurities. Elements can be effectively extracted with high purity. And the last residue that remains as an impurity is the gas element.
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