1. Choice of the decomposition process of tungsten mineral raw material

Decomposition of tungsten ore is the most important working procedure of tungsten smelting process,the decomposition technology desides the choice of raw materials and the whole process development.Tungsten mineral mainly consists of wolframite and scheelite and mixed ore.From the view of thermodynamics,tungsten minerals can decompose with inorganic acid and alkali,in addition,the chemical reaction of carbonate, fluoride and phosphate solution of alkali metal.Consider all the practical factors,soda pressure leaching,caustic soda leaching,decomposition and sintering of soda water immersion method would be better.At the same time, the theory proves that the high temperature chloride method and the fluoride method can also be used to decompose the tungsten ore, but it is not used in the actual production.Although WO3 leaching rate is very high, and the process is very short,alkali leaching process is limited by the capacity of equipment, and can not applied widely.

 

If we set workshop annual capacity APT about 1000t,considering various factors from the composition of raw material and product regulations, business model and investment perspective,a clear contrast is to choose caustic soda leaching method.Caustic soda leaching method is mainly used for low calcium wolframite concentrate.Because of its low reaction equilibrium constant, low reagent consumption, low temperature requirement and short reaction time, high rate decomposition.caustic soda can also decomposite scheelite when the high temperature,high basicity and a certain amount of additives exist,and tht decomposition rate reached 99%.The amount of caustic soda was significantly less than the amount of soda.

 

2. The choice of purification process.Purification removal process determines whether the APT product quality standards or not.With the continuous development of tungsten industry, purification industry also continues to make progress, especially in the separation of tungsten and molybdenum. At present, the main methods of purifying crude sodium ion in industry are: classical chemical purification, solution extraction, ion exchange and so on. Different methods have their own properties, but linked to each other and mutual penetration, for example, the solution extraction using precipitation purification method to get rid of impurities.

 

For ammonium paratungstate production process analysis 1/3, please see in http://news.chinatungsten.com/en/tungsten-information/81822-ti-10584.