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A hardmetal drill scrap (old scrap) may be recycled by a chemical process to extract both tungsten and cobalt (the constituents of such a hardmetal). The resulting tungsten oxide may be converted to tungsten metal powder and used to produce a heavy metal alloy (first-use product) for counterweights (end-use product) in airplanes.
Methods for recycling tungsten can be broadly divided into two types: direct methods and indirect methods. Direct methods mean that tungsten scrap is transformed into powder of the same composition by either chemical or physical treatment, or a combination of both. A typical example of the direct methods is the zinc treatment method.
Tungsten products manufactured from scrap by chemical (ie indirect) recycling have exactly the same properties and performance as tungsten products made from tungsten concentrate (primary raw material) due to the purification steps in the process.
Tungsten recycling is expected to keep growing at about 8% per year over the next five years, increasing global production of recycled tungsten materials from 23% of total supply in 2012 to 28% of global supply in 2018. The main regions for growth in tungsten recycling are most likely to be Europe and Asia, as collection programs for tungsten ...
Tungsten recycling is that procedure that is used for making repeated use of the metal. With the increasing utilization of the metal, it could be said that the scrap of that valuable metal must not be wasted. The more the metal is precious, the more effective the recycling process should be rendered. It is the duty of the industry professional ...
Tungsten Recycling: An Overview. Tungsten is an important and rare metal with a concentration in the earth's crust of about 1.5 parts per million (ppm). Due to its unique combination of mechanical and thermal properties, tungsten is considered a valuable material that must be sustainably managed and utilised.
Recycling of tungsten 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 (average coil weight: <30 mg; absolutely not economic to recycle), welding electrodes and chemical uses is low.
Recycling of tungsten 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.
Recycling – a plus for business partners and the environment. H.C. Starck Tungsten Powders is a world leader in the recycling of materials containing tungsten. Thanks to decades of experience, we are able to extract pure tungsten from almost all forms of tungsten scrap and production waste. The quality of the reclaimed raw material is ...
The other part comes from the recycling and reuse of solid waste slag and terminal consumer product waste from the tungsten production process, such as waste cemented carbide, tungsten materials, alloy steel, tungsten contact materials, and chemical catalysts. This part accounts for about 24 %.
chemical process to extract both tungsten and cobalt (the constituents of such a hardmetal). The resulting tungsten oxide may be converted to tungsten metal powder and used ... the tungsten recycling rate is mainly influenced by its use in …
The common tungsten extraction methods are surface (or open pit) mining and sub-surface (or underground) mining, or a combination of both. Modern tungsten processing methods dissolve scheelite and wolframite concentrates by an alkaline pressure digestion, and tungsten can also be recycled from Scrap.
Tungsten carbide (WC) is chemically a binary compound of tungsten and carbon in the stoichiometric ratio of 93.87% tungsten and 6.13% carbon. However, industrially the term usually implies cemented tungsten carbides (CWC); a sintered powdered metallurgical product consisting of very fine grains of pure tungsten carbide bound or cemented together in a …
Other tungsten containing scrap and residues might require a modified process. Clean cemented carbide inserts and compacts are converted to powder 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).
In yet another direct recycling process, tungsten carbide scrap is first thermally bloated and then crushed. The bloating and crushing method of recycling the scrap metal is based upon the embrittling effect when cemented carbide is heated to about 1800 °C followed by rapid quenching.
In the case of tungsten, the expression recycling is further divided into direct recycling, indirect recycling (also called chemical recycling) and semi-direct recycling (a combination of both), which is explained in more detail in a separate "Newsletter" dealing with recycling technologies.
10%The process developed at CSIR-NML for their recycling is superior to presently practiced APT based chemical processing technologies in terms of: (1) higher tungsten and other valuable metal recovery efficiencies (98% vs 85–90%); (2) low capital investment and operating costs (capital and operating costs are ~50% of the currently …
Direct recycling is a quality specific process in terms of chemical composition, tungsten carbide grainsize and foreign substance contamination. In keeping with this requirement, scrap of high purity is treated in this process.
With the continuous improvement of the recycling rate of tungsten secondary resources in various countries, the technology of tungsten resource recycling is also increasing. Common methods include mechanical crushing method, saltpeter method, zinc melting method, electrolysis method, leaching method, reduction method, roasting-ammonia leaching method, etc.
Tungsten Metal Powder- This chemical recycling generally use furnace installed in boats or rotator furnaces which heated between 700-1000 degree Celsius. Tungsten Carbide- It is obtained from tungsten metal powder after reacting with pure carbon powder, for example- carbon black, at 900 – 2200°C in batch or pusher furnaces, a process known ...
Tungsten in the form of finely divided powder is highly flammable and may ignite spontaneously on contact with air. Powdered tungsten may also cause fire or explosion on contact with oxidants (HSDB 2009; NIOSH 2016). Exhibit 1: Physical and Chemical Properties of Elemental Tungsten (ATSDR 2005; NIEHS 2003; NIOSH 2016) Property Value
US-8617985-B2 chemical patent summary.
34 · Industrialization of Tungsten Recovering from Used Cemented Carbide Tools 3. Features of Newly Developed Tungsten Recycling Technology Carbide tool recycling methods are roughly classi-fied into two types: direct and indirect. The direct method processes hard scrap into powder with the chemical composition intact. The indirect method