Posted on Dec 4 2011 at 07:25:43 PM in B2B
Tungsten Process,Tungsten Ore Dressing,Tungsten Processing Machine
Most tungsten concentrates are processed chemically to ammonium paratungstate. Secondary raw materials like (oxidized) scrap and residues are another important feed for chemical tungsten processing (Single Toggle Jaw Crusher usually used). Wolframite concentrates can also be smelted directly with charcoal or coke in an electric arc furnace to produce ferrotungsten which is used as alloying material in steel production. Pure scheelite concentrate may also be added directly to molten steel.
Recycling is an important factor in the world's tungsten metal supply. It is estimated that today some 30% is recycled, and the tungsten ore processing industry is able to treat almost every kind of tungsten-containing scrap and waste to recover tungsten and, if present, other valuable constituents.
Contaminated cemented carbide scrap, turnings, grindings machine are oxidized and chemically processed to APT in a way similar to that used for the processing of tungsten metal ores. If present, cobalt, tantalum and niobium are recovered in separate processing lines. Other tungsten containing scrap and residues might require a modified process.
Clean cemented tungsten carbide inserts and compacts are converted to powder (Flour Grinding Mill Costs) by the zinc process (treatment with molten zinc which is dissolved in the cobalt phase and is then distilled off, leaving a spongy material which is easily crushed). This powder is added back to the manufacture of ready-to-press powder. By this process, not only tungsten carbide but also cobalt, tantalum carbide and other carbides are recycled.
Recycling of tungsten metal in high speed steel is high, and a typical melt contains 60 to 70% scrap, including internally generated scrap. On the other hand, recycling in such applications as lamp filaments, welding electrodes and chemical uses is low. Although tungsten seems to be relatively harmless to the environment, environmental concerns have led to an increasing recycling rate, especially when the material contains other metals in addition to tungsten. Recycling is always more environmentally friendly and usually more economic than waste disposal.