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Research on the Extraction of Molybdenum and Tungsten

Author: ZhangHui
Tutor: LiuZhen
School: Henan University of Science and Technology
Course: Chemical processes
Keywords: tungsten molybdenum extraction complex solvent
CLC: TD925.6
Type: Master's thesis
Year: 2013
Downloads: 20
Quote: 0
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Abstract


Molybdenum, a rare and refractory metal, has many good qualities, and is widelyused in the alloy, aerospace, chemical products and other fields. However, it isdifficult to seperate tungsten from molybdenum because of their similar ionic radius,atomic structure and chemical properties by the influence of the lanthanide contractionand their being often symbioticin in minerals and wastes. In addition, tungsten andmolybdenum are short in resources, single concentrates are less and less and thedemaning of tungsten and molybdenum products, especially the numeroussophisticated use of the desired product impurities increasingly grows. Therefore,tungsten and molybdenum separation research has the vital significance.In this paper, the influence of single extractant and mixed extractant on theextraction of tungsten and molybdenum under different conditions of temperature,concentration and distribution ratio was studied by selecting the TBP、TOA、P204、N1923as the extraction agent and sulfonated kerosene as the diluent. Using X-raypowder diffraction (XRD), scanning electron microscope (SEM), infrared spectra (IR)technology,the reaction mechanism of the extraction process was analyzed.Researches show that:1.In the process of tungsten and molybdenum separation and extraction, theacidity has important influence on the extraction process. If the acidity is toohigh,emulsification phenomenon easily happens, which is not conducive to theconduct of extraction.2.In the process of extracting tungsten and molybdenum by single extractant, theextraction ratio decreases with increasing temperature, which indicates extractionreaction is exothermic process..Besides, the molybdenum extraction rate increaseswith the increasing volume of extraction solvent and extraction time. Among the fourkinds of extractants, N1923extraction works best with extraction rate up to96.87%under the condition of acidity between pH=2-3, temperature at25℃, extraction time 15min, oscillation time3min and N1923: sulfonated kerosene=4:13. In the complex solution, the molybdenum extraction rate first increases andthen decreases as the temperature increases,25℃for the highest extraction rate.Specifically speaking, With (N1923+P204) as the complex solution, the molybdenumextraction rate is up to98.97%and the separation factor is11.74, which increased by33.7%compared with that by single extractant under the condition of acidity betweenpH=3-4, the temperature at25℃, the extraction separation time15min,oscillationtime3min and (N1923+P204): sulfonated kerosene=4:1,

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