EP0011475B1 - Recovery of tungsten values from tungsten-bearing materials - Google Patents

Recovery of tungsten values from tungsten-bearing materials Download PDF

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Publication number
EP0011475B1
EP0011475B1 EP79302549A EP79302549A EP0011475B1 EP 0011475 B1 EP0011475 B1 EP 0011475B1 EP 79302549 A EP79302549 A EP 79302549A EP 79302549 A EP79302549 A EP 79302549A EP 0011475 B1 EP0011475 B1 EP 0011475B1
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EP
European Patent Office
Prior art keywords
tungsten
values
ore
water
roasted
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Expired
Application number
EP79302549A
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German (de)
French (fr)
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EP0011475A1 (en
Inventor
George Stephen James
Alfred Murray Harris
Gwilym James Rees
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anglo American Corp of South Africa Ltd
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Anglo American Corp of South Africa Ltd
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Priority to AT79302549T priority Critical patent/ATE1681T1/en
Publication of EP0011475A1 publication Critical patent/EP0011475A1/en
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Publication of EP0011475B1 publication Critical patent/EP0011475B1/en
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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

Definitions

  • Tungsten is generally found in nature in scheelite type ores and wolframite type ores. These two ores differ substantially in their chemical composition being a calcium tungstate and an iron-manganese tungstate, respectively. Consequently, different processes have generally been used to recover the tungsten values from each type of ore.
  • the classical prior art process is to treat the ore with hydrochloric acid to produce insoluble tungstic acid.
  • the tungstic acid is taken up in an ammonia solution to produce ultimately ammonium paratungstate (APT).
  • APT ammonium paratungstate
  • Wolframite on the other hand is usually decomposed by fusing the ore with sodium hydroxide/sodium carbonate which extracts the tungsten as sodium tungstate.
  • the cooled fused product is leached with water to extract the soluble sodium tungstate.
  • this may be treated with hydrochloric acid to precipitate tunstic acid which is taken up in an ammonia solution to produce APT.
  • British patent specification No. 1,089,913 describes a process for recovering tunsten values from both scheelite and wolframite type ores or concentrates.
  • This process comprises fusing powdered scheelite and/or wolframite type ores or concentrates with a fluxing mixture of sodium carbonate, sodium chloride and sodium nitrate (which mixture also contains, in the case of the starting material containing calcium, at least sufficient siliceous material to form calcium silicate therewith), leaching the cooled, fused material with water and separating a tungsten-bearing alkaline leach liquor from water-insoluble impurities, acidifying the separated leach liquor and adding thereto sufficient of a fluoride or hydrofluoric acid to form compounds which are substantially insoluble in organic media, extracting the thus-treated material with an organic solution comprising an organic amine capable of forming a water-insoluble organic amine tungsten complex to transfer tungsten from the aqueous to the organic phase, separating the phases, treating the separated organic
  • This process involves, as an essential step, the fusion of powdered scheelite and/or wolframite type ores or concentrates with a mixture of sodium carbonate and sodium chloride. Indeed, it is stated in the specification that a fluid melt should be produced. Typical temperatures at which the fusion take place are 698°C to 825°C.
  • Fox U.S. Patent No. 3,800,025 describes a process of extracting tungsten values from low grade tungsten ores which includes the steps of roasting a particulated tungsten-containing ore in a water containing atmosphere in the presence of sodium chloride and at least one of the reagents selected from sodium carbonate and sodium phosphate at a temperature in the range of about 600°C to about 900°C for about 1 to 3 hours, water leaching the resulting calcines to dissolve soluble tungsten values and filtering.
  • This process is restricted in application to low grade tungsten ores and requires a water containing atmosphere for its operation.
  • relatively high roast temperatures and relatively low amounts of sodium reactant are generally used.
  • French Patent Specification 992821 describes a process for extracting tungsten values from low grade tungsten-containing slags in which a mixture of crushed slag and an alkali metal salt is roasted at a temperature below the melting point and the roasted product is leached in order to extract tungsten values.
  • tungsten bearing ore or concentrate is a high grade ore or concentrate which is a mixture of wolframite and scheelite and that after extraction of the water-soluble values from the roasted product, the latter is roasted again, without fusion, in the presence of the reagent and further water-soluble tungsten values are extracted from the re-roasted product.
  • roasting takes place without general fusion, that is the mix of ore or concentrate and reagent must not form a fluid melt during roasting.
  • a melt is not produced confers a much greater flexibility in process design and can result in energy savings.
  • the roasted product is an easily handleable material.
  • the tungsten values in the roasted product will be in the form of water-soluble alkali metal tungstate.
  • This product may thereafter be treated in known manner to recover the tungsten values as tungsten metal.
  • the tungsten values may be water leached from the roasted mixture and the leach liquor then treated in the manner described in British patent specification No. 1,089,913. These treatment steps are essentially an application of chemistry known in the art.
  • the tungsten-bearing ore or concentrate is ⁇ - high grade one, i.e. one containing at least 20 percent by weight tungsten as tungsten oxide (W0 3 ). Such materials may contain up to 80.5 percent by weight tungsten as tungsten oxide.
  • the reagent is an alkali metal chloride, an alkali metal carbonate or a mixture thereof.
  • the alkali metal for both the chloride and the carbonate reagent is preferably sodium. It is a particularly preferred feature of the process that the reactive composition consists solely of an alkali metal carbonate, such as sodium carbonate. It has surprisingly been found that excellent tungsten recoveries, at relatively mild temperatures can be achieved using sodium carbonate alone.
  • the roasting temperature will vary according to the nature of the ore or concentrate being treated and the type and quantity of reagent. The important point is that a temperature must be chosen which will not result in fusion bf the mixture of ore or concentrate and reagent taking place, but will yet be high enough for the desired reaction to take place in a reasonable time. As a general rule temperatures in the range 600° to 800°C will be used.
  • the step of re-roasting the extracted material in the presence of further reagent and extracting tungsten values from the re-roasted material can be repeated until as much of the tungsten as desired has been extracted from the ore.
  • the amount of reagent present during roasting will also vary according to the nature of the ore or concentrate. There should be at least sufficient sodium present to combine with all the tungsten to form sodium tungstate and it is generally preferred to use a stoichiometric excess of sodium.
  • the roasting must take place for a sufficient time to convert as much as possible of the tungsten to sodium tungstate.
  • the roasting time is typically up to 120 minutes, although for many ores no particular advantage has been found by heating for a period of longer than 60 minutes.
  • the reagent may also contain a suitable oxidising agent, such as sodium nitrate. It may be desirable in some cases to include finely divided silica in the reactive composition. The silica reacts with the calcium to form tricalcium silicate which is subsequently readily separable from the sodium tungstate.
  • the tungsten-bearing ore or concentrate and the reagent will generally both be provided in finely divided state and will be intimately mixed prior to roasting.
  • the product may be leached with water. It has been found experimentally that one leach and a replacement wash under appropriate conditions are generally sufficient.
  • leaching may take place on the roasted product as such without subjecting that product to a crushing or like step. Moreover, leaching may take place while the roasted product is still hot.
  • the leach liquor is treated by commonly known methods to remove impurities such as aluminium, magnesium, phosphorous, silicon, antimony, arsenic and molybdenum.
  • the filtrate may be further purified by treatment with a fluoride or hydrofluoric acid.
  • the adequately purified solution is then subjected to a conventional solvent extraction procedure.
  • the tungsten contained in the organic phase may be extracted with ammonium hydroxide to provide an aqueous ammonium tungstate solution.
  • Tungsten metal powder may be produced from the ammonium tungstate by known methods.
  • the ore (or extracted residue) and reagent was in finely divided or particulate form and was roasted as a mixture. After roasting, the sodium tungstate was leached with water, the residue separated from the leach liquor by filtration and washing and the leach liquor treated in the manner generally described above to recover the tungsten values.
  • a scheelite concentrate containing 74.8% of W0 3 and a wolframite concentrate containing 68.1% W03 were mixed 1:1 by weight and the mixture was mixed with sodium carbonate in the proportion of 1 part of sodium carbonate to four parts of the mixture.
  • the specific quantities used were 300 g of scheelite, 300 g of wolframite and 150 g of sodium carbonate (the theoretical stoichiometric amount of sodium carbonate was 98 g).
  • the final mixture was roasted at 650°C for four hours. After roasting, the material was leached with water as described above to give a percentage extraction of tungsten of 58%.
  • the overall tungsten extraction is 90 and 95 percent at residue: Na 2 CO 3 ratios of 7:3 and 1:3.
  • the particular ratio chosen will depend on the particular economic circumstances under which-the process is, operated at any given time.

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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)
  • Inorganic Compounds Of Heavy Metals (AREA)

Description

  • Tungsten is generally found in nature in scheelite type ores and wolframite type ores. These two ores differ substantially in their chemical composition being a calcium tungstate and an iron-manganese tungstate, respectively. Consequently, different processes have generally been used to recover the tungsten values from each type of ore. In the case of scheelite ores, the classical prior art process is to treat the ore with hydrochloric acid to produce insoluble tungstic acid. The tungstic acid is taken up in an ammonia solution to produce ultimately ammonium paratungstate (APT). Wolframite on the other hand is usually decomposed by fusing the ore with sodium hydroxide/sodium carbonate which extracts the tungsten as sodium tungstate. The cooled fused product is leached with water to extract the soluble sodium tungstate. Similarly, this may be treated with hydrochloric acid to precipitate tunstic acid which is taken up in an ammonia solution to produce APT.
  • British patent specification No. 1,089,913 describes a process for recovering tunsten values from both scheelite and wolframite type ores or concentrates. This process comprises fusing powdered scheelite and/or wolframite type ores or concentrates with a fluxing mixture of sodium carbonate, sodium chloride and sodium nitrate (which mixture also contains, in the case of the starting material containing calcium, at least sufficient siliceous material to form calcium silicate therewith), leaching the cooled, fused material with water and separating a tungsten-bearing alkaline leach liquor from water-insoluble impurities, acidifying the separated leach liquor and adding thereto sufficient of a fluoride or hydrofluoric acid to form compounds which are substantially insoluble in organic media, extracting the thus-treated material with an organic solution comprising an organic amine capable of forming a water-insoluble organic amine tungsten complex to transfer tungsten from the aqueous to the organic phase, separating the phases, treating the separated organic phase, with aqueous ammonia to form a water-soluble ammonium tungstate, and separating the aqueous phase containing ammonium tungstate from the organic phase. This process involves, as an essential step, the fusion of powdered scheelite and/or wolframite type ores or concentrates with a mixture of sodium carbonate and sodium chloride. Indeed, it is stated in the specification that a fluid melt should be produced. Typical temperatures at which the fusion take place are 698°C to 825°C.
  • Fox U.S. Patent No. 3,800,025 describes a process of extracting tungsten values from low grade tungsten ores which includes the steps of roasting a particulated tungsten-containing ore in a water containing atmosphere in the presence of sodium chloride and at least one of the reagents selected from sodium carbonate and sodium phosphate at a temperature in the range of about 600°C to about 900°C for about 1 to 3 hours, water leaching the resulting calcines to dissolve soluble tungsten values and filtering. This process is restricted in application to low grade tungsten ores and requires a water containing atmosphere for its operation. Moreover, relatively high roast temperatures and relatively low amounts of sodium reactant are generally used.
  • French Patent Specification 992821 describes a process for extracting tungsten values from low grade tungsten-containing slags in which a mixture of crushed slag and an alkali metal salt is roasted at a temperature below the melting point and the roasted product is leached in order to extract tungsten values.
  • We have now developed an improved method of recovering tungsten values from mixtures of wolframite and scheelite.
  • According to the present invention, we provide a method of recovering tungsten values from a tungsten-bearing ore or concentrate in which the ore or concentrate is roasted, without fusion, in the presence of a reagent which is an alkali metal chloride or carbonate or a mixture thereof and water-soluble tungsten values are extracted from the roasted product, characterised in that the tungsten bearing ore or concentrate is a high grade ore or concentrate which is a mixture of wolframite and scheelite and that after extraction of the water-soluble values from the roasted product, the latter is roasted again, without fusion, in the presence of the reagent and further water-soluble tungsten values are extracted from the re-roasted product.
  • It is essential to the process that roasting takes place without general fusion, that is the mix of ore or concentrate and reagent must not form a fluid melt during roasting. The fact that a melt is not produced confers a much greater flexibility in process design and can result in energy savings. The roasted product is an easily handleable material.
  • The tungsten values in the roasted product will be in the form of water-soluble alkali metal tungstate. This product may thereafter be treated in known manner to recover the tungsten values as tungsten metal. For example, the tungsten values may be water leached from the roasted mixture and the leach liquor then treated in the manner described in British patent specification No. 1,089,913. These treatment steps are essentially an application of chemistry known in the art.
  • The tungsten-bearing ore or concentrate is α- high grade one, i.e. one containing at least 20 percent by weight tungsten as tungsten oxide (W03). Such materials may contain up to 80.5 percent by weight tungsten as tungsten oxide.
  • The reagent is an alkali metal chloride, an alkali metal carbonate or a mixture thereof. The alkali metal for both the chloride and the carbonate reagent is preferably sodium. It is a particularly preferred feature of the process that the reactive composition consists solely of an alkali metal carbonate, such as sodium carbonate. It has surprisingly been found that excellent tungsten recoveries, at relatively mild temperatures can be achieved using sodium carbonate alone.
  • The roasting temperature will vary according to the nature of the ore or concentrate being treated and the type and quantity of reagent. The important point is that a temperature must be chosen which will not result in fusion bf the mixture of ore or concentrate and reagent taking place, but will yet be high enough for the desired reaction to take place in a reasonable time. As a general rule temperatures in the range 600° to 800°C will be used.
  • The step of re-roasting the extracted material in the presence of further reagent and extracting tungsten values from the re-roasted material can be repeated until as much of the tungsten as desired has been extracted from the ore.
  • The amount of reagent present during roasting will also vary according to the nature of the ore or concentrate. There should be at least sufficient sodium present to combine with all the tungsten to form sodium tungstate and it is generally preferred to use a stoichiometric excess of sodium.
  • The roasting must take place for a sufficient time to convert as much as possible of the tungsten to sodium tungstate. The roasting time is typically up to 120 minutes, although for many ores no particular advantage has been found by heating for a period of longer than 60 minutes.
  • Where necessary, depending on the ore composition and/or type of heating equipment being used, the reagent may also contain a suitable oxidising agent, such as sodium nitrate. It may be desirable in some cases to include finely divided silica in the reactive composition. The silica reacts with the calcium to form tricalcium silicate which is subsequently readily separable from the sodium tungstate.
  • The tungsten-bearing ore or concentrate and the reagent will generally both be provided in finely divided state and will be intimately mixed prior to roasting. After roasting, the product may be leached with water. It has been found experimentally that one leach and a replacement wash under appropriate conditions are generally sufficient. The fact that there is no fusion during roasting means that leaching may take place on the roasted product as such without subjecting that product to a crushing or like step. Moreover, leaching may take place while the roasted product is still hot.
  • After leaching, the leach liquor is treated by commonly known methods to remove impurities such as aluminium, magnesium, phosphorous, silicon, antimony, arsenic and molybdenum.
  • After the first purification step, the filtrate may be further purified by treatment with a fluoride or hydrofluoric acid. The adequately purified solution is then subjected to a conventional solvent extraction procedure. The tungsten contained in the organic phase may be extracted with ammonium hydroxide to provide an aqueous ammonium tungstate solution.
  • Tungsten metal powder may be produced from the ammonium tungstate by known methods.
  • In order that the invention may be more fully understood, the following example is given by way of illustration.
  • In this exampfe, the ore (or extracted residue) and reagent was in finely divided or particulate form and was roasted as a mixture. After roasting, the sodium tungstate was leached with water, the residue separated from the leach liquor by filtration and washing and the leach liquor treated in the manner generally described above to recover the tungsten values.
    • Example
  • A scheelite concentrate containing 74.8% of W03 and a wolframite concentrate containing 68.1% W03 were mixed 1:1 by weight and the mixture was mixed with sodium carbonate in the proportion of 1 part of sodium carbonate to four parts of the mixture. The specific quantities used were 300 g of scheelite, 300 g of wolframite and 150 g of sodium carbonate (the theoretical stoichiometric amount of sodium carbonate was 98 g). The final mixture was roasted at 650°C for four hours. After roasting, the material was leached with water as described above to give a percentage extraction of tungsten of 58%.
  • The extracted residue was again mixed with sodium carbonate and roasted at 650°C and two tests conducted with different amounts of sodium carbonate. The results are given in Table I.
    Figure imgb0001
  • The overall tungsten extraction is 90 and 95 percent at residue: Na2CO3 ratios of 7:3 and 1:3. The particular ratio chosen will depend on the particular economic circumstances under which-the process is, operated at any given time.

Claims (2)

1. A method of recovering tungsten values from a tungsten-bearing ore or concentrate in which the ore or concentrate is roasted, without fusion, in the presence of a reagent which is an alkali metal chloride or carbonate or a mixture thereof and" water-soluble tungsten values are extracted from the roasted product, characterised in that the tungsten-bearing ore or concentrate is a high grade ore or concentrate which is a mixture of wolframite.and scheelite and that after extraction of the water-soluble values from the roasted product, the latter is roasted again, without fusion, in the presence of the reagent and further water-soluble tungsten values are extracted from the re-roasted product.
2. A method according to claim 1 characterised in that the roasted product is leached with water while it is hot in order to extract tungsten values therefrom.
EP79302549A 1978-11-17 1979-11-13 Recovery of tungsten values from tungsten-bearing materials Expired EP0011475B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT79302549T ATE1681T1 (en) 1978-11-17 1979-11-13 PRODUCTION OF TUNGSTEN FROM A BASE MATERIAL CONTAINING TUNGSTEN.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ZA786478A ZA786478B (en) 1978-11-17 1978-11-17 Recovery of tungsten values from tungsten-bearing materials
ZA786478 1978-11-17

Publications (2)

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EP0011475A1 EP0011475A1 (en) 1980-05-28
EP0011475B1 true EP0011475B1 (en) 1982-10-20

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Country Status (12)

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EP (1) EP0011475B1 (en)
JP (1) JPS595657B2 (en)
AR (1) AR224633A1 (en)
AT (1) ATE1681T1 (en)
AU (1) AU525137B2 (en)
BR (1) BR7907441A (en)
CA (1) CA1136422A (en)
DE (1) DE2963902D1 (en)
ES (1) ES486063A1 (en)
PT (1) PT70465A (en)
TR (1) TR21615A (en)
ZA (1) ZA786478B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8034319B2 (en) 2003-05-30 2011-10-11 Jfe Mineral Co., Ltd. Method for producing complex oxide of metal

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JPS6176854U (en) * 1984-10-24 1986-05-23
US10607435B2 (en) 2007-04-11 2020-03-31 Cfph, Llc Game of chance display
US8216056B2 (en) 2007-02-13 2012-07-10 Cfph, Llc Card picks for progressive prize
US8764541B2 (en) 2006-09-19 2014-07-01 Cfph, Llc Secondary game
US8393954B2 (en) 2006-12-29 2013-03-12 Cfph, Llc Top performers
US8070582B2 (en) 2007-03-01 2011-12-06 Cfph, Llc Automatic game play
US8398489B2 (en) 2007-04-05 2013-03-19 Cfph, Llc Sorting games of chance
US8932124B2 (en) 2006-08-31 2015-01-13 Cfph, Llc Game of chance systems and methods
US8500533B2 (en) 2007-08-29 2013-08-06 Cfph, Llc Game with chance element and strategy component that can be copied
US8758111B2 (en) 2008-08-20 2014-06-24 Cfph, Llc Game of chance systems and methods
JP2013536002A (en) 2010-07-22 2013-09-19 ザ プロクター アンド ギャンブル カンパニー Outer cover for absorbent articles
US9078792B2 (en) 2011-06-30 2015-07-14 The Procter & Gamble Company Two-piece wearable absorbent article having advantageous front waist region and landing zone configuration
US9060905B2 (en) 2013-03-08 2015-06-23 The Procter & Gamble Company Wearable absorbent articles
US9078789B2 (en) 2013-03-08 2015-07-14 The Procter & Gamble Company Outer covers and disposable absorbent inserts for pants
CN105969977B (en) * 2016-07-05 2018-06-22 江西理工大学 A kind of method that tungsten is extracted from scheelite
CN109897962B (en) * 2019-03-14 2020-11-17 厦门钨业股份有限公司 Method and device for recovering tungsten in tungsten-containing waste by adopting oxidation smelting method
CN114956181A (en) * 2022-05-19 2022-08-30 崇义章源钨业股份有限公司 Method for removing potassium in scheelite by roasting waste acid liquor
CN115433840B (en) * 2022-08-24 2023-06-02 崇义章源钨业股份有限公司 Method for separating and recovering tungsten and tin in fine-fraction black-white tungsten-tin bulk concentrate
CN115747530B (en) * 2022-11-23 2023-12-01 郑州大学 Method for separating and extracting molybdenum and tungsten from molybdenum-tungsten bulk concentrate

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US2187750A (en) * 1936-07-31 1940-01-23 Marvin Metals Inc Treatment of ores
US2394362A (en) * 1943-03-30 1946-02-05 Us Vanadium Corp Treatment of tungsten ores
US2501952A (en) * 1944-08-07 1950-03-28 Bennett Preble Method for the alkaline roasting of an acidic oxide ore
FR992821A (en) * 1949-05-31 1951-10-23 Roechlingsche Eisen & Stahl Process for recovering tungsten and tungsten compounds from slag containing tungsten
US3256057A (en) * 1962-10-26 1966-06-14 Burwell Blair Process of recovering high purity tungsten compositions from tungsten-bearing ores
GB1089913A (en) * 1964-10-23 1967-11-08 Alfred Gordon Evans Robiette Recovery of tungsten values from ores
US3800025A (en) * 1972-03-30 1974-03-26 Union Carbide Corp Recovery of tungsten from low grade tungsten ores

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8034319B2 (en) 2003-05-30 2011-10-11 Jfe Mineral Co., Ltd. Method for producing complex oxide of metal

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AU5291879A (en) 1980-05-22
ZA786478B (en) 1980-02-27
BR7907441A (en) 1980-07-08
JPS595657B2 (en) 1984-02-06
ATE1681T1 (en) 1982-11-15
JPS5589446A (en) 1980-07-07
TR21615A (en) 1984-11-29
AU525137B2 (en) 1982-10-21
DE2963902D1 (en) 1982-11-25
EP0011475A1 (en) 1980-05-28
CA1136422A (en) 1982-11-30
ES486063A1 (en) 1980-09-01
AR224633A1 (en) 1981-12-30
PT70465A (en) 1979-12-01

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