The process of tungsten smelting mainly includes the following steps, which are aimed at extracting and purifying tungsten elements from tungsten ores:
- Raw material preparation and pretreatment
Ore beneficiation
According to the content and physical properties of tungsten in the ore, suitable tungsten ore is selected for smelting.
Crushing and Grinding
The selected ore is crushed and ground finely for subsequent operations such as beneficiation and flotation.
- Physical Separation
Selection
Separate the crushed ore by physical or chemical methods, mainly separating tungsten ore and impurities in tungsten ore.
Flotation
The selected ore is subjected to flotation treatment, using methods such as chemicals and air bubbles to separate tungsten ore from flotation bubbles and further improve the purity of tungsten ore.
Third, chemical treatment
Sintering
The ore after flotation is subjected to sintering treatment to remove impurities and sulfur from it.
Melting and refining:
Melting
The sintered ore is heated with an oxidizing agent to melt it.
Refining
Pure tungsten is obtained by cooling and crystallizing.
- Reduction and Extraction
Double-carbon reduction method: Pure tungsten and graphite are heated together at high temperature, so that the reduction reaction occurs and metallic tungsten is obtained.
- Subsequent treatment
Processing treatment: The obtained tungsten metal is processed and treated, including forging, calendering, welding, etc., so as to make it have specific shape and performance.
- Selection of process methods
Pyrometallurgy
Acid method
It is suitable for tungstic acid ore with high tungsten content, by reducing tungstic acid ore into acidized sodium tungstate at high temperature, and then adding sodium carbonate to reduce it into tungsten powder.
Alkali Method
It is suitable for the smelting of low tungstate, by converting the ore into ammonium tungstate by alkali under high temperature, and then obtaining tungsten metal through the process of heating, separating and drying.
Aluminum oxide reduction method
It is the most widely used method at present. Firstly, tungsten powder and alumina are mixed, and the reducing agent is added to pyrolyze together to obtain tungsten powder, and then sintering, hot pressing and other processes to obtain metallic tungsten.
Carbon and silicon thermal reduction method
It is suitable for tungsten ore with low content but high silicon content. Under high temperature, tungsten oxide in tungsten ore is reduced with carbon containing reductant and siliceous material to obtain tungsten-iron alloy, and then tungsten metal is obtained by liquid phase refining.
VII. Environmental protection and safety
In the whole smelting process, attention needs to be paid to environmental protection and safety supervision to ensure the sustainability and environmental friendliness of the production process.
To summarize, the process of tungsten smelting is a complex process involving multiple steps such as raw material preparation, physical separation, chemical treatment, reduction and extraction, and subsequent treatment. When choosing a smelting process, it is necessary to select a suitable process method according to the composition and characteristics of the ore, as well as the requirements of the product. Meanwhile, environmental protection and safety are also important aspects of the smelting process that cannot be ignored.
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