MetallurgyTechniques - Recovery of Tungsten Values from Low Grade Ore

Type of Technology : Indigenous

Area of Technology : Material and Material Science

Details of Present/existing/Technology. Shortfall/Technological gaps in the existing technology

Due to high density and high temperature properties, tungsten is a very important metal both strategically and industrially. Most of the present demand is met through imports of powder and concentrates. The available Indian deposits are of very low grade ranging from 0.04 to 0.2 % WO₃ against the commonly exploited ore grades of 0.5% WO₃ world over.

The existing process for the beneficiation of tungsten ore basically consists of processing of the ore by physical methods like gravity and magnetic separation to get the concentrate. But considering the low metal content and the fine dissemination of tungsten bearing minerals in the gangues in the run-of-mine ore, normally it is difficult to get the desired grade of the concentrate. Alternatively, efforts of obtaining a high grade concentrate by fine sized pulverisation and multi-stage processing leads to high losses of tungsten values. There has been a need to develop a suitable process for the recovery of tungsten values from lean grade ores. The new technology addresses this problem.

Approach adopted in new technology to evade technological gap in the existing one

The new technology developed at the National Metallurgical Laboratory, Jamshedpur adopts an integrated approach combining physical and chemical beneficiation methods to get the final product : ammonium para tungstate. In order to avoid tungsten losses in the fine size ranges, prior to final concentration, pre-concentration of the ore is carried out at relatively coarser size.

Advantage

The advantages of this technology includes the following :

• Higher recovery of tungsten values and the process results in the final product as ammonium para tungstate by a combination of physical & chemical methods.
  
• Reductions in energy towards comminution of ore by carrying out pre-concentration at relatively coarser size.

Reduction in water consumption because pre-concentration is a dry processing step etc.

Brief description

Extensive characterisation and physical & chemical beneficiation studies were undertaken at the National Metallurgical Laboratory, Jamshedpur on different tungsten ore samples from a typically low grade deposit located in Degana, Rajasthan, India. Based on these studies a process has been developed for the recovery of tungsten values from the low grade tungsten ore. The process basically consists of pre-concentration of the ore at relatively coarser size by dry magnetic separation, further upgradation by gravity methods followed by chemical processing to ammonium para tungatate.

Applications

Mineral, Metals & Materials
Lamp filaments, High speed tools, Wear resistant parts, Engine valves, Circuit breakes Chemicals for textiles etc.

Status of Development

Laboratory/Pilot plant scale

Ecological/Environmental Impact

No toxic effluents are generated in this process and as such it has no adverse effect on environment

Technology Transfer Assistance Offered

Evaluation of raw materials, Process know-how, Process flow-sheet, Equipment details. Advice and assistance in setting up the plant and operation on separate terms and conditions.

Contact for more information:

Director
National Metallurgical Laboratory
Jamshedpur-831 007, India

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