System and method for preparing ammonium metavanadate crystals

[0050] Example 1

[0051] The structural schematic diagram of the system for preparing ammonium metavanadate of this embodiment is as figure 1 Shown.

[0052] The system includes the following units connected in sequence: a conversion reaction tank 1, a horizontal filter press 2, a filtrate buffer tank 3, a heat exchanger 4, a crystallizer 5, a thickener 6, a crystal slurry storage tank 7 and a horizontal A filter press 8, wherein a mother liquor storage tank 9 is provided between the thickener 6 and the horizontal filter press 8 for collecting supernatant;

[0053] The discharge port at the bottom of the conversion reaction tank 1 is connected to the horizontal filter press 2 through a feed pipe, and the upper discharge port of the conversion reaction tank 1 is formed with the feed pipe through a first return line Circulation loop

[0054] A second return line is provided between the horizontal filter press 2 and the first return line;

[0055] The pore size of the filter cloth of the

[0063] Example 2

[0064] In this example, the system described in Example 1 is used to prepare ammonium metavanadate, and the specific steps are:

[0065] 1) Circulate the mixture of calcium vanadate conversion solution and ammonium metavanadate solution in the conversion reaction tank 1 at a temperature of 95°C in the first return line for 3 minutes, close the first return line, and open the second return line Keep the slurry in the horizontal filter press 2 with a pore size of 15 μm for 2 minutes to form a filter cake layer, close the second return line, and collect the filtrate into the filtrate buffer tank 3;

[0066] 2) The obtained filtrate is transferred from the filtrate buffer tank 3 to the tube heat exchanger 4 at a temperature of 55°C by a transfer pump. After the first cooling, it is transferred to the continuous crystallizer 5 at a temperature of 35°C for the second Cool down twice to obtain crystal slurry;

[0067] 3) Transport the crystal slurry described in step 2) to t

[0070] Example 3

[0071] In this example, the system described in Example 1 is used to prepare ammonium metavanadate, and the specific steps are:

[0072] 1) Circulate the calcium vanadate conversion solution with a temperature of 90℃ in the conversion reaction tank 1 in the first return line for 5 minutes, close the first return line, and open the second return line so that the slurry has a diameter of 5μm. The horizontal filter press 2 is maintained for 3 minutes to form a filter cake layer, the second return line is closed, and the filtrate is collected in the filtrate buffer tank 3;

[0073] 2) The obtained filtrate is transferred from the filtrate buffer tank 3 to the tube heat exchanger 4 at a temperature of 50°C by a transfer pump. After the first cooling, it is transferred to the continuous crystallizer 5 at a temperature of 40°C for the second Cool down twice to obtain crystal slurry;

[0074] 3) Transport the crystal slurry described in step 2) to the thickener 6, the solid c