摘要:
A process for the soda ash digestion of refractory tungsten concentrates is provided, the process comprising forming a slurry of the concentrate in an aqueous solution to which sodium carbonate is added in stages while digesting the slurry in an autoclave at a selected elevated temperature of at least about 180.degree. C. to control the concentration of the sodium carbonate during digestion to provide high extraction yields of the contained WO.sub.3. The total amount of the Na.sub.2 CO.sub.3 added stage-wise to complete the digestion is substantially inversely correlated to the digestion temperature and substantially directly correlated to the Na.sub.2 CO.sub.3 /WO.sub.3 weight ratio such as to effect dissolution of at least about 97%, and generally at least about 98%, of the WO.sub.3 in the concentrate and provide a pregnant liquor containing WO.sub.3, the stage-wise addition of the sodium carbonate being such as to inhibit the dissolution of gangue minerals, such as silica, contained in the concentrate.
摘要翻译:提供了一种用于对难熔钨精矿进行苏打灰消化的方法,该方法包括在阶段中加入碳酸钠的水溶液中形成浓缩物的浆液,同时在高压釜中以选定的升高的温度至少消化浆料 约180℃以控制消化期间碳酸钠的浓度,以提供含有WO 3的高提取产率。 逐步添加以完成消化的Na 2 CO 3的总量与消化温度基本上成反比,并且与Na 2 CO 3 / WO 3重量比基本上直接相关,例如至少约97%的溶解,并且通常至少约 98%的浓缩物中的WO 3,并提供含有WO 3的怀孕液体,逐步加入碳酸钠以抑制浓缩物中所含的脉石矿物如二氧化硅的溶解。
摘要:
A process is disclosed for recovering tungsten and molybdenum values from tungsten concentrates containing molybdenum in an amount at least about one-twentieth of the amount of contained WO.sub.3. The concentrate, generally a wolframite concentrate, is subjected to dissolution in hot NaOH solution to provide a pregnant liquor or solution containing tungsten and molybdenum values. The solution, after purification, is treated with a sulfide precipitation agent to precipitate MoS.sub.3 and some WS.sub.3 using a stoichiometric excess of a sulfide precipitating agent to produce a filtrate containing tungsten substantially free of molybdenum. The sulfide precipitate is dissolved in dilute NaOH solution and again precipitated using a stoichiometric deficient amount of the sulfide precipitating agent to produce a precipitate of MoS.sub.3 low in tungsten. The foregoing sulfide precipitation steps may be reversed.
摘要:
A process for conditioning a tungsten concentrate containing tungsten as WO.sub.3, sulfur as sulfide, and calcite to fix at least a portion of the sulfur as calcium sulfate by reaction with the calcite, comprises providing a tungsten concentrate having a calcite content such that less than about 15 wt. % calcium sulfate based on the weight of the WO.sub.3 in the concentrate will be formed and heating the concentrate to a temperature of at least about 500.degree. C. in an oxidizing atmosphere to oxidize substantially all the sulfur in the concentrate to provide a conditioned concentrate having a calcium sulfate content less than about 15% based on the weight of the WO.sub.3, whereby the conditioned concentrate can be efficiently leached with alkali metal carbonates or hydroxides and the resulting alkali metal tungstate solution can be effectively treated to recover an ammonium tungstate solution.
摘要:
A continuous process with feedback control is disclosed for the soda ash digestion of tungsten concentrates in which a slurry of the concentrate in an aqueous sodium carbonate solution is digested in an autoclave at a temperature of at least about 180.degree. C. to provide a pregnant solution of WO.sub.3. High dissolution efficiency is maintained during digestion by continuously monitoring the pregnant solution which includes determining the specific gravity and the Na.sub.2 CO.sub.3 concentration of the pregnant liquor from which feedback signals are produced which are used to control the amount of Na.sub.2 CO.sub.3 and H.sub.2 O fed to the slurry in accordance with the digestion conditions predetermined to provide the desired dissolution efficiency.
摘要翻译:公开了一种具有反馈控制的连续方法,用于苏打灰消除钨精矿,其中浓缩物在碳酸钠水溶液中的浆液在高压釜中在至少约180℃的温度下消化以提供怀孕溶液 的WO3。 在消化期间通过连续监测怀孕溶液来维持高溶解效率,其包括确定产生反馈信号的怀孕液体的比重和Na 2 CO 3浓度,其用于控制按照下列方式供给到浆料中的Na 2 CO 3和H 2 O的量 预定消化条件以提供所需的溶解效率。
摘要:
A process for the soda digestion of mixed wolframite and scheelite concentrates is provided, the process comprising forming a slurry of the mixed wolframite and scheelite concentrates in an aqueous sodium carbonate solution and then digesting the slurry in an autoclave at a temperature of at least about 180.degree. C. During digestion a predetermined amount of sodium hydroxide is added calculated stoichiometrically to react with NaHCO.sub.3 formed as a result of the hydrolysis of FeCO.sub.3 or FeCO.sub.3 and MnCO.sub.3 produced during the digestion of the wolframite and convert it to Na.sub.2 CO.sub.3. The concentration of the Na.sub.2 CO.sub.3 solution is substantially inversely correlated to the digestion temperature and substantially directly correlated to the Na.sub.2 CO.sub.3 /WO.sub.3 weight ratio ranging from about 0.9 to 2 such as to effect dissolution of at least about 95% of the WO.sub.3 in the concentrate and provide a pregnant liquor containing said WO.sub.3.
摘要翻译:提供了一种用于混合的白钨矿和白钨矿浓缩物的苏打水消解的方法,该方法包括将混合的黑钨矿和白钨矿精矿的浆料形成在碳酸钠水溶液中,然后在高压釜中在至少约180℃的温度下消化浆料 在消化期间,按化学计量计算加入预定量的氢氧化钠,与作为在硫酸镁消化过程中产生的FeCO 3或FeCO 3和MnCO 3的水解产生的NaHCO 3反应并将其转化为Na 2 CO 3反应。 Na 2 CO 3溶液的浓度与消化温度基本上成反比,并且与Na 2 CO 3 / WO 3重量比基本上直接相关,其范围为约0.9至2,例如至少约95%的WO 3在浓缩物中的溶解,并提供 含有WO3的怀孕液体。
摘要:
Vanadium and nickel values are selectively recovered from a petroleum coke residue by slurrying the coke in an aqueous solution of sodium carbonate providing an excess of the stoichiometric amount of sodium for formation of sodium vanadate and sodium sulfate, and then digesting the slurry at moderately elevated temperature in a pressurized autoclave under an oxygen overpressure supplying at least the stoichiometric amount of oxygen based on the vanadium and sulfur content of the slurry and advantageously sufficient additional oxygen to provide the thermal requirements of the digestion step by oxidation of carbon. In a continuous embodiment, the feed slurry temperature and feed solids content are adjusted according to a substantially inversely correlated relationship. The digestion temperature for a given total pressure and gas flow rate in the autoclave is adjusted to generate a pregnant liquor containing about 20 gpl to about 100 gpl of vanadate (V.sub.2 O.sub.5) from which at least about 50% of the input water has been converted to steam during the digestion. The vanadate liquor is separated from the digestion residue, which is then sequentially selectively leached for recovery therefrom of nickel and residual vanadium values.
摘要:
A process for extracting tungsten values from an aqueous phase into an organic phase, comprises(a) providing an aqueous phase containing tungsten values dissolved therein, and having an initial pH of about 2.2 to about 4.0,(b) providing an organic phase depleted in tungsten and containing a secondary amine or tertiary amine extractant, a modifier, and the balance a liquid hydrocarbon solvent,(c) extracting tungsten values from said aqueous phase into said organic phase in a plurality of extraction stages operating in countercurrent fashion, and(d) recovering the organic phase enriched in tungsten values and an aqueous raffinate having a pH of about 0.3 to about 4.5.
摘要:
Basic sodium tungstate leach liquor is treated to reduce the concentration dissolved therein of silica, phosphorus and fluorine impurities in a process which comprises providing a small but effective amount of magnesium in the liquor to maximize removal of silica and phosphorus from solution in the liquor while maintaining the liquor temperature between about 60.degree. C. and about 100.degree. C. and the liquor pH between about 9 and about 11, filtering the liquor, adjusting the liquor pH to between about 6 and about 8 and the liquor temperature to between about 20.degree. C. and about 60.degree. C., and then providing a small but effective amount of aluminum hydroxide in the filtered liquor to maximize removal of fluorine from solution in the liquor while maintaining the liquor temperature between about 20.degree. C. and about 60.degree. C. and the liquor pH between about 6 and about 8.
摘要:
Dissolved molybdenum is removed from sodium tungstate solutions by adding sulfuric acid to lower the pH value of the solution to between about 8 and about 5, adding to the sodium tungstate solution a water-soluble sulfide in an amount of at least 0.5 gram per liter (gpl) in excess of that required to precipitate as sulfides molybdenum and certain other metals, then lowering the pH value of the sodium tungstate solution to between about 4.0 and about 1.5 as rapidly as possible with sulfuric acid in such a way as to precipitate molybdenum trisulfide while minimizing co-precipitation of tungsten.
摘要:
A process for the soda ash digestion of scheelite concentrates is provided, the process comprising forming a slurry of a scheelite concentrate in an aqueous sodium carbonate solution and then digesting the slurry in an autoclave at an elevated temperature of at least about 180.degree. C. The concentration of the Na.sub.2 CO.sub.3 solution is substantially inversely correlated to the digestion temperature and substantially directly correlated to the Na.sub.2 CO.sub.3 /WO.sub.3 weight ratio such as to effect the selective dissolution of at least about 95% of the WO.sub.3 in the concentrate and provide a pregnant liquor containing WO.sub.3 while inhibiting substantial dissolution of gangue minerals.
摘要翻译:提供了一种用于白钨矿浓缩物的纯碱消解的方法,该方法包括在碳酸钠水溶液中形成白钨矿浓缩物的浆料,然后在至少约180℃的升高的温度下在高压釜中消化浆料。 Na 2 CO 3溶液的浓度与消化温度基本上成反比,并且与Na 2 CO 3 / WO 3重量比基本上直接相关,例如使浓缩物中至少约95%的WO 3的选择性溶解,并提供含有WO3 同时抑制脉石矿物的大量溶解。