Tungsten Ore Flotation Organic Inhibitor – Oxalic Acid

Among tungsten ore flotation inhibitor, sodium silicate is the most widely used one. But when encounters some complex accompanying tungsten mine deposition, sodium silicate may become useless. 

So not only high effective collecting agent is needed, inhibitor is also necessary. Although organic inhibitor can not deal with every case like sodium silicate, it has diverse structure and has good selectivity for mineral. It is promoted in recent years.

Oxalic acid exists in plants, it has wide resource. It is colorless column crystal, soluble in water, insoluble in diethyl ether and other organic solvent, is slightly toxic. Oxalic acid can be used to inhibit calcite, barite and garnet during tungsten ore flotation.

Oxalic acid mainly deals with calcite in tungsten scheelite. Calcite is a calcium carbonate mineral, there aggregation can be a bunch of crystal, or grain, block, fibrous, bell-like, soily, is fragile and can be easily cracked if is stroke. It is calcium ion structure like calcium tungstate, so they are difficult to be separated. It is the main reason why scheelite is cheap. So eliminates calcite is vital for scheelite.

Chemical formula of oxalic acid is H₂C₂O₄, there are many strong hydrophilic group which will chelates with surface lattice ion of calcite to form Ca²⁺ chelating. For organic inhibitor, inhibiting activity depends on numbers and types of polar group. There are two –COOH polar hydrophilic group in oxalic acid and there is no hydrocarbyl which will lower inhibiting activity. However, its efficiency is far lower than citric acid and tartaric acid, its advantages may be cheap. In practical application, oxalic acid is easy to obtain, has wide access and stable chemical property. It is effective for calcite, barite and garnet. So it can be considered if main gangues in tungsten concentrate are above three.                  

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