Chromium doped ammonium paratungstate may be produced by doping chromium (Cr) in evaporation crystallization process during the production of ammonium paratungstate. Adopting chromium acetate (CH3COO)3Cr (analytical reagent) and ammonium tungstate solution obtained by dissolving high-purity WO3 with ammonia water as…

Arsenic doped ammonium paratungstate may be prepared by adopting simple arsenic, nitric acid solution and ammonium paratungstate (APT) as raw materials and forming in liquid phase, the preparing steps are as below: 1. Dissolve a certain amount of simple arsenic…

Sodium doped ammonium paratungstate may be used to prepare coarse grain size tungsten trioxide (WO3), and the content of sodium (Na) may affect the particle size of tungsten (W) powder prepared by WO3. APT with high sodium content may be…

Coarse ammonium paratungstate has advantages of large apparent density and good fluidity, and its demand increases year by year as customers are requiring more and more strictly on the performance of subsequent products now. Preparation of Coarse Ammonium Paratungstate 1.…

Super grade ammonium paratungstate is ammonium paratungstate with grade of APT-0, which is divided by national standard. Generally, traditional process to prepare high-purity ammonium paratungstate is first to dissolve super grade ammonium paratungstate by ammonia-dissolving method, and then evaporation recrystallization.…

Grade 1 ammonium paratungstate is a national standard product of APT with grade of APT-1. The ammonium paratungstate may be obtained by the process of losing ammonia in ammonium tungstate solution. Its chemical equation is as follows: 12(NH4)2WO4→5(NH4)2O•12WO3•nH2O+(7-n)H2O+14NH3↑ Ammonium tungstate…

APT crystalline mother liquor’s main components are ammonium chloride, ammonium tungstate, a small amount of sulfur ions and sulfate ions. Tungsten and ammonia in mother liquor of APT crystal can be recovered by adopting one-step method, calcium hydroxide or calcium…

Ammonium paratungstate hexahydrate’s chemical formula is (NH4)10H2W12O42•6H2O (APT•6H2O). Stability of Ammonium Paratungstate Hexahydrate It is key to generate ammonium paratungstate tetrahydrate ((NH4)10H2W12O42•4H2O or APT•4H2O) from aqueous solution of ammonium tungstate in the production of tungsten powders. Studies have shown that…

Ammonium paratungstate tetrahydrate or APT•4H2O may be prepared by crystallization process from pure ammonium tungstate solution by batch process and continuous process. But APT•4H2O will lose part of crystal water in the drying process of this industrial production. Therefore, repeated…

Large grain size ammonium paratungstate is an important intermediate product in the preparation of tungsten powder from tungsten concentrates. The physical properties of APT such as particle size, particle size distribution, and crystal morphology have an important influence on the…