Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B34/00—Obtaining refractory metals
  • C22B34/30—Obtaining chromium, molybdenum or tungsten
  • C22B34/36—Obtaining tungsten
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
  • C22B5/04—Dry methods smelting of sulfides or formation of mattes by aluminium, other metals or silicon
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
  • C22B5/00—General methods of reducing to metals
  • C22B5/02—Dry methods smelting of sulfides or formation of mattes
  • C22B5/06—Dry methods smelting of sulfides or formation of mattes by carbides or the like

Definitions

• the present invention refers to a method for producing tungsten in oxidic form from tungsten ore.
• the method according to the invention consists of a series of steps, each of which is known in its principle.
• the invention gives the unexpected effect that the various methods now applied can be replaced by a single process, which further gives the possibility to process low grade ores with a high yield. This is not possible with known technique.
• the oxide is eventually reduced, e.g. with hydrogen tungsten powder.
• ore reduction reducing agents such as ferro silicon, calcium silicon, magnesium-silicon, aluminium, silicon calcium carbide, carbon, or the like.
• ferro silicon and aluminium because they make possible compact equipment and high recoveries.
• the reduction is suitably carried out in an arc furnace in a carbon crucible at a temperature of about 15002000 C., usually 1800- 2000 C. The temperature is dependant of ore composition, the type of ore and gangue, and of the reducing agent.
• the metallic ingot formed in the reduction gets the same general composition regardless of whether the ore is of scheelite or wolframate type.
• the essential influence of different ore types is on the iron content of the ingot. If this content should be too high for some ore a correction can easily be made by mixing with a suitable ore of low iron content.
• the digestion of the crushed tungsten ingot can be carried out for example by melting with alkali nitrate and/0r sodium carbonate whereby tungsten is converted into a water soluble form.
• the ingot can also be treated with acids, like aqua regia, or with acids followed by alkali, e.g. sodium carbonate or hydroxide, in Water solution.
• Tungsten is normally precipitated as ammonium paratungstate (by adding ammonia), or as tungstic acid.
• One further advantage with the invention is that fractions with lower tungsten content than what is normally used, can be utilized. This means for instance that the upgrading of the ore does not have to be carried as far as is presently needed, which can result in lower upgrading costs and more important higher yield of tungsten.
• a gangue as well as certain impurities are separated by reducing the ore to metal.
• the subsequent digestion will therefore be technically substantially simpler, require less chemicals and less time, and also give a better yield than is possible with conventional technique.
• the invention has made it technically and economically possible to process poor and highly impure ores, which is of great value with the present relatively limited supply of rich tungsten ores.
• a method of recovering tungsten oxide from tungsten ores which comprises:
• a reducing agent selected from the group consisting of ferrosilicon, calcium-silicon, magnesium-silicon, aluminum, silicon, calcium carbide and carbon,
• heating said charge to an elevated reducing tempera- 4 ture range from about 1500 C. to 2000 C. to form a melt of slag and a bath of molten metal comprising tungsten, separating said molten metal from said slag and any separable metal phases present, solidifying said molten tungsten metal to form an ingot thereof, crushing said ingot, and then treating said crushed ingot by digestion in a liquid comprising a melt selected from the group group consisting of at least one of the digestion agents alkali metal nitrate and sodium carbonate to form tungsten oxide, or a liquid consisting of an acid solution to form a solution of tungsten which is thereafter precipitated as tungsten oxide by making the solution alkaline.
• a liquid comprising a melt selected from the group group consisting of at least one of the digestion agents alkali metal nitrate and sodium carbonate to form tungsten oxide, or a liquid consisting of an acid solution to form a solution of tungsten which is thereafter precipitated as tungsten oxide by

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacture And Refinement Of Metals (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=20258988

Family Applications (1)

Country Status (4)

Cited By (1)

Family Cites Families (1)

• 1971
  • 1971-02-15 SE SE01871/71A patent/SE350073B/xx unknown
• 1972
  • 1972-02-14 US US00226255A patent/US3767761A/en not_active Expired - Lifetime
  • 1972-02-14 DE DE2206893A patent/DE2206893A1/de active Pending
  • 1972-02-15 FR FR7205057A patent/FR2125487B1/fr not_active Expired

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