The process of tungsten wet smelting can be clearly divided into the following steps:
- Raw material processing
Ore crushing
Firstly, tungsten ore is crushed to smaller lumps by mechanical or artificial crushing for subsequent processing.
Grinding and Screening
The crushed ore is ground to achieve a certain fineness, usually requiring more than 90% of the ore particle size less than 0.043mm. Screening is used to further separate the different particle size of the ore, to improve the efficiency of the subsequent leaching process.
Second, leaching
Alkaline leaching
The finely ground tungsten ore is mixed with sodium hydroxide (NaOH) solution for alkaline leaching. Under appropriate temperature (e.g. 150~170℃) and pressure, tungsten in tungsten ore reacts with sodium hydroxide to form soluble sodium tungstate (Na2WO4). This process is usually carried out in a mechanically agitated tank to increase the reaction efficiency and leaching rate.
Acid leaching (for scheelite)
For scheelite, acid leaching can be used. Commonly used acids are sulfuric acid and hydrochloric acid. Under appropriate temperature and acid concentration, scheelite reacts with acid to produce crude tungstic acid.
III. Solid-liquid separation
Filtration or centrifugal separation: solid-liquid separation of the leached slurry to remove the ore residue and unreacted ore. Commonly used separation methods are filtration and centrifugal separation.
Fourth, solution purification and enrichment
Purification
Through precipitation, ion exchange or solvent extraction methods, remove impurity ions in the solution, such as silicon, phosphorus, arsenic, etc., in order to improve the purity of tungsten compounds.
Enrichment
Increase the concentration of tungsten compounds in the solution by evaporation and concentration, crystallization and other methods to facilitate the subsequent extraction steps.
- Extraction of metallic tungsten or intermediate compounds of tungsten
Reduction
Mix the purified sodium tungstate solution with reducing agent (e.g. carbon, aluminum powder) and carry out reduction reaction under high temperature to produce metallic tungsten powder.
Electrolysis or other methods
According to product requirements, electrolysis or other methods can be used to extract metallic tungsten or intermediate compounds of tungsten from the solution.
The tungsten wet smelting process mainly includes the steps of raw material treatment, leaching, solid-liquid separation, solution purification and enrichment, and extraction of metallic tungsten or tungsten intermediate compounds. In each step, attention needs to be paid to controlling the corresponding process parameters and operating conditions to ensure efficient extraction of tungsten and product purity. At the same time, attention needs to be paid to environmental protection and appropriate measures need to be taken to minimize the discharge of waste water, waste gas and solid waste.
More details of ammonium metatungstate product, please visit website: http://ammonium-metatungstate.com/
Please contact CHINATUNGSTEN for inquiry and order of ammonium metatungstate:
Email: sales@chinatungsten.com
Tel.: 86 592 5129595
