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Sodium tungstate dihydrate may be prepared by different methods such as alkaline hydrolysis, crystallization, extraction, soda solution pressure cooking, and so on. Alkaline Hydrolysis to Prepare Sodium Tungstate Dihydrate Step 1: Wolframite ore is crushed to 320 mesh, and alkaline hydrolysis is carried out in reactor with 30% caustic soda. The reaction equation is as follows: MnWO4?FeWO4+4NaOH→2Na2WO4+Fe(OH)2?Mn(OH)2 Step 2: The reaction product obtained in step 1 is reacted with calcium chloride to obtain calcium tungstate. The reaction equation is as…

Analytical reagent sodium tungstate is referred to as sodium tungstate that meets the purity standards, which ensures the scientific precision and reliability of chemical analysis, chemical reaction or physical testing. Coprecipitation Separation of Trace Impurities in Sodium Tungstate and Determination by ICP-AES Using lanthanum hydroxide as co-precipitant, trace metal impurity elements (calcium, cadmium, zinc, iron, manganese, nickel, and zinc) in sodium tungstate were coprecipitated, separated, enriched, and measured by ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). Analytical reagent means the sodium…

Sodium tungstate crystal may be prepared by the crystallization of sodium tungstate solution. Removal of Arsenic and Silicon from Sodium Tungstate Solution by Crystallization The removal of arsenic and silicon from impure Na2WO4 solution was investigated by crystallization using the liquors (m(As)/m(WO3)=0.32×10-3~2.94×10-3, m(Si)/m(WO3)=1.26×10-3~5.84×10-3) from middle-grade mixed wolframite and scheelite concentrate decomposed with NaOH by mechanical activation and tungsten residue leached by traditional digestion. The influences of the crystallization ratio and the addition of Al2O3 on removing impurities of As and…

Sodium polytungstate has been found to be used as heavy-liquid to separate and concentrate materials by density with the deepening of research. For example, it can be used to separate the worn carbon composites in brake pads. Sodium polytungstate is a kind of inorganic heavy-liquid with the characteristics of high density and cyclic utilization. And it is nontoxic and easily prepared. Also, the sodium polytungstate density separation operation is simple and stable, and most importantly the physic-chemical property of matter…

Sodium tungstate solution containing high impurities should be purified. Purification of Sodium Tungstate Solution with High Impurities Sodium tungstate solution out of sodium phosphate decomposition of scheelite contains high impurities. To solve this problem, the purifying effects of fluoride (F), phosphorous (P), silicon (Si) and arsenic (As) by basic magnesium carbonate was studied. Effects of basic magnesium carbonate dosage, pH value, reaction temperature, reaction time on impurities purifying were researched. The removal mechanism of impurities was also researched. The results…

Reagent grade sodium tungstate, RG sodium tungstate for short, may be applied for precision analysis and scientific research. Reagent-grade chemical substances are labeled red. There are a variety of chemical reagents, so that it is difficult to prepare them into multiple grades or different specifications at the same time. So, it is hard to obtain reagents of the required purity or grade sometimes. And therefore, it is of significance for users to know how to purify reagents. There are many…