Ammonium Paratungstate(APT) Granular Control
There’re many factors affecting the physical properties (grain size and grain size distribution, morphology, density, etc.), purity and particle size control of ammonium paratungstate , mainly the temperature of the solution, over saturation, stirring intensity, evaporation rate and crystallization rate. Respectively, this article talks about the impact of various factors on the particle size of ammonium paratungstate under control.
1. Temperature
| No. | Evaporation Crystallization Temperature/ ℃ | Apparent Density/ g·cm-3 |
| 1 | 60-70 | 1.36-1.65 |
| 2 | 84-88 | 1.60-1.70 |
| 3 | 90-94 | 1.66-1.85 |
| 4 | 95-100 | 1.82-2.01 |
2. Agitation Intensity
| No. | Agitation Speed / r·min-1 | FSSS Granularity / μm |
| 1 | 85 | 30 |
| 2 | 62 | 40 |
| 3 | 50 | 42 |
| 4 | 40 | 45 |
3. Agitation Time
| No. | Agitation Time/ min | Apparent Density/ g·cm-3 |
| 1 | 30 | 1.40-1.80 |
| 2 | 60 | 1.80-1.95 |
| 3 | 120 | 1.66-2.20 |
| 4 | constant stirring | 2.20-2.40 |
4. Supersaturation
| No. | (NH4)2WO4 solution g/L |
NH4Cl g/L |
NH3 g/L |
FSSS Granularity / μm |
| 1 | 125 | 100 | 30 | 30 |
| 2 | 115 | 65 | 40 | 39 |
| 3 | 113 | 40 | 40 | 42 |
| 4 | 120 | 80 | 40 | 38 |
| 5 | 114 | 60 | 40 | 40 |
5. Others
Heating rate, evaporation time.
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