The purpose is to study a new process method suitable for the production of low tantalum and low miscellaneous niobium, which is not only simple in process, easy to operate, reduce material consumption, but also can control the cost increase to the minimum, and has obvious advantages in quality compared with similar products.
The niobium purification method for producing low tantalum niobium and low miscellaneous Niobium by using the industrial grade ordinary reverse niobium solution as raw material with sec-octanol primary extraction is characterized in that it consists of A and partial secondary extraction by the following three processes. With N - 503 + 40% and 60% of volume ratio of organic liquid mixture of kerosene, with 1.3 1.6 moL/L - H2SO4 and 2-3 moL/L HF solution for 2-octyl alcohol system of industrial-grade ordinary niobium liquid with low acid under the condition of some secondary extraction, niobium in the ordinary niobium liquid fluorine complex 30 ~ 40%, 80 to 90% of the remaining tantalum fluorine complex extraction to the organic phase, forming load organic phase mixture, and get more in the water phase has significantly reduced the low liquid tantalum niobium tantalum content.
Tantalum-niobium concentrate is ground, decomposed with hydrofluoric acid and sulfuric acid, and an aqueous solution or slurry containing tantalum-niobium is prepared after acid adjusting. Then the fluorocomplex of niobium and tantalum is extracted into the organic phase with organic solvents such as MIBK, secondary octanic acid and N-503. And separate it from other impurities. In order to remove a small amount of impurity elements brought into the organic phase during the extraction process, the organic phase was washed with sulfuric acid solution and a small amount of impurity was transferred into the aqueous phase. The washed organic phase containing tantalum and niobium fluoride complex was extracted back into the aqueous phase with dilute sulfuric acid. In the reverse extraction of niobium fluoride complex, a small amount of tantalum fluoride complex will enter the niob-containing aqueous phase. However, the content of tantalum and other impurity elements in the niobium solution obtained by such an extraction is relatively high. The available data show that tantalum is at 0.05 ~ 0.1% level and other impurities are at 0.005 ~ 0.01% level. Although this process can meet the requirements of general industrial grade niobium oxide and metal niobium products, it is difficult to meet the quality requirements of low tantalum and low miscellaneous niobium. Two is currently our recognized mature after blunt niobium method is secondary extraction under the condition of high acidity and oxalic acid solution crystallization purification process of niobium, these two kinds of suitable for the production of optical glass and single crystal of high purity niobium pentoxide, defect is high cost and small scale production, not suitable for mass production than high purity niobium level is low, the low price low tantalum niobium and niobium products.
