98% sodium tungstate dihydrate may be studied by TG-DTG technology to know its dehydration process. And the non-isothermal kinetic data of the dehydration process is analyzed using the thermal analysis kinetic data processing method proposed by Malek et al. Processing Methods of Kinetic Data Malek et al. proposed a relatively complete set of kinetic data processing methods. The steps are as follows: 1. Activation energy E was calculated using Ozawa method and Kissiger method among the multiple scanning rate method.…

Industrial grade sodium tungstate dihydrate is also known as technical grade sodium tungstate dihydrate with molecular formula of Na2WO4•2H2O. The thermal decomposition of Na2WO4•2H2O and its kinetics was studied in a static air by TG-DTG. The thermal decomposition process of the Na2WO4•2H2O occurred in one stage. By the kinetic method of processing thermal analysis data put forward by Malek et al, it is defined that the kinetics model for the dehydration process in SB (m, n). The activation energy E…

Chemically pure sodium tungstate is a good inhibitor for carbon steel in simulated seawater, and the inhibition efficiency increased with the increase of inhibitor concentration, and the adsorption of sodium tungstate onto the surface of carbon steel followed the amended Langmuir adsorption isotherm equation. Composite of sodium tungstate and SLS has better corrosion performance than that of sodium tungstate alone, which shows excellent synergistic effect. Compound inhibitor has higher efficiency, with lower Tafel slope on the cathode and anode and…

High purity sodium tungstate dihydrate is a colorless or white crystalline powder that can be decomposed by strong acids into tungstic acid (water-insoluble). It is easily weathered in dry air. And it is stable in air, but heated to lose crystal water into anhydrous salt at 100°C. Besides, it is soluble in water and insoluble in ethanol. High purity sodium tungstate dihydrate can be applied for the preparation of tungstic acid, and tungstate, etc. And it can also be used…

Industrial grade sodium tungstate is also known as technical pure (TP) sodium tungstate, whose purity is lower than that of guarantee grade (GR), analytical grade (AR), chemical purity (CP) and laboratory purity (LR). These grades are classified in accordance with different uses. The TP sodium tungstate is suitable for the laboratories which are not so strict on the purity requirements. There are many ways to control equipment corrosion in industrial cooling water systems, among which adding corrosion inhibitors is one…

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…