Using impregnation method to produce zirconium tungstate, there are the producing processes as follow:
1.Taking a amount of ZrOCl2 • 8H20 dissolve in an appropriate amount of deionized water, and then drop ammonia to form hydrogel, to adjust the PH value of 9.0.
2.After place hydrogel at room temperature for 12h suction filtered and then using deionized water washed the precipitate until no chlorine ions. The filter cake was then soaked in ethanol and alcoholization in the oven for 12h, after cooling to room temperature then taken out, filtered to remove residual ethanol, dried at 383K, finely ground to obtain a white powdery zirconium hydroxide carrier.
3. The resulting Zr(OH) 4 precursors are impregnated by the following three ways to obtain catalyst:
(1) Preparation a small amount of ammonium metatungstate solution to soak irconium hydroxide powder with stirring to make them thoroughly mixed, dried and calcined at different temperatures to prepare a catalyst, referred to as WZH(A).
(2)The zirconium hydroxide powder was immersed in ammonium metatungstate solution, dried and distilled off the water at different firing temperatures, to prepare a catalyst referred to as WZH(B).
(3) The processes is similar to(2), but change ammonium metatungstate solution to ammonium tungstate solution, to prepare a catalyst referred to as WZH(C).

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Mineralogical examinations were performed to characterize the formation of secondary minerals of tungsten ore and natural removal process of dissolved As and trace metals (Pb, Zn and Cu) from sulfide oxidation. Laboratory-based leaching tests were also conducted to determine whether the concentrations of As and trace metals in the leachates from waste-rock materials and contaminated soil could be affected by the presence acids such as acid rainwater or acid mine drainage. Waste-rock materials and contaminated soil were compared by 4-day leaching tests using HNO3 solutions of increasing acidity (0.00001–0.1 mole/L). Mineralogical studies of the waste rocks confirmed the presence of Fe-(oxy)hydroxides (e.g. goethite), jarosite, elemental S, Fe-sulfates, amorphous Fe–As phases, anglesite and covellite as secondary minerals. These secondary minerals act as mineralogical scavengers of dissolved trace metals, View the MathML source and acidity released by sulfide oxidation. Arsenic was attenuated by the adsorption on Fe-(oxy)hydroxides and/or the formation of an amorphous Fe–As phase, with a Fe/As ratio = 1 (maybe scorodite: FeAsO4 · 2H2O). Electron probe microanalyses data showed that the Fe-(oxy)hydroxides had high concentrations of Pb (up to 21 wt%), with appreciable amounts of As (up to 7.7 wt%), Zn (up to 4.6 wt%) and Cu (up to 2.5 wt%) indicating that dissolved metals were co-precipitated and adsorbed onto Fe-(oxy)hydroxides, Fe(Mn)-hydroxides and Fe-sulfates.

The results of the leaching experiments within the pH-range 3.5–5.0 indicated that acidic rainstorms may leach minor amounts of Pb (ca. 1.7–4.0% of total), Zn (ca. 0.8–2.2% of total), Cu (ca. 0.0–0.2% of total) and As (ca. 0.02–0.1% of total) from waste rocks, including the dissolution of soluble secondary minerals previously formed during prolonged dry periods, while dissolution of these elements was negligible from the contaminated soil. In the pH-range 1.0–3.0, the leaching of Pb (ca. 2.4–31% of total) and As (ca. 0.1–5.8% of total) from the waste rocks was significant, which could influence the concentration of these metals in mine runoff. Strongly acidic solutions may also appreciably dissolve Zn (0.0–48% of total) and Cu (0.0–34% of total) in contaminated soil. Leach tests showed that the formation of less soluble secondary minerals had high retention of As, Pb, Zn and Cu, unless their solubilities were increased after the addition of strongly acidic solutions (pH of below 2.0). The precipitation of secondary minerals and the adsorption of trace metals are efficient mechanisms for decreasing the mobilities of As and other trace metals in the surface environment.

 

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Zirconium tungstate is a green light powder. Chemical formula of zirconium tungstate is ZrW2O8 and the molecular weight is 586.9. Its relativity system numbers are as follows: CAS number: 16853-74-0, MDL number: MFCD00168096, EINECS number: 240-876-3. It is stable at room temperature and atmospheric pressure, but should to avoid the light, flame and heat. Besides, it can be sealed and stored in tight, dry and airy place where away from light. Although ZrW2O8 to water is not harmful, but if there is no relevant government license, the material can not discharged into the surrounding environment. There are many ways for produce zirconium tungstate such as impregnation method, oxide direct synthesis method, co-precipitation method, combustion method, sol-gel method, spray drying method and hydrothermal synthesis method and so on.
Zirconium tungstate as raw materials are mainly used in engineering ceramics, electronic ceramics, metal matrix composites, ceramic matrix composites, cement-based composite materials, the optical devices, dental materials. In addition, because the unique cubic crystal structure of zirconium tungstate it can as the negative thermal expansion material which has been widespread concern.

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Tungsten mine waste mud (TMWM) was investigated for its potential use as repair material of ordinary portland cement (OPC) concrete. Bond strength between OPC concrete substrate and three repair materials was analysed. TMWM geopolymeric binder and two commercial repair products were used as repair materials. Bond strength behaviour was assessed from slant shear tests. A total of 128 slant shear specimens were made in order to evaluate bond strength at 1, 3, 7 and 28 days curing. Four kinds of concrete substrate surface treatment were used, as cast against metallic formwork, as cast against wood formwork, saw cut and acid etching. This study indicates that TMWM geopolymeric binders possess very high bond strength even at early ages and that behaviour is not affected by low surface treatment roughness. Commercial repair products on the other hand show very low bond strength and are very dependent on surface treatment roughness. Scanning electron micrographs reveal that TMWM geopolymeric binders chemically bond to the concrete substrate, while cost comparisons show this geopolymeric repair solution is by far the most cost efficient.

 

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