Tungsten and Molybdenum Separation - Paratungstate B Guanidine Salt Precipitation Method
Paratungstate B guanidine salt precipitation method is a method for separating molybdenum and tungsten. It is known that there are three kinds of orthopolyacids, namely, paratungstic acid A, paratungstic acid B, paratungstic acid Z, the structure of B is the most special, and its chemical formula is Na 10 [H 2 W 12 O 42 ], containing two H atoms, so the selectivity is strongest. The key point of B guanidine precipitation method is how to convert A into B. Scholars have found that SiO 2 has a significant catalytic effect on the transition reaction, and can shorten the conversion process to a few hours, which makes the feasibility of B guanidine salt precipitation method. After the conversion of sec-tungstic acid A to paratungstic acid B, the pH of the solution was increased from 6.7 to 8.1, ensuring that Mo 4 2- could be polymerized in a large concentration range, in order to use guanidine salt precipitation agent can effectively separate and in suitable conditions of pH tun...