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1.发明授权
公开(公告)号：US4330508A
公开(公告)日：1982-05-18
申请号：US200126
申请日：1980-10-24
CPC分类号： C01B19/001
摘要： A process for removing dissolved selenium IV values from an acidic aqueous copper sulphate solution includes passing the solution through a tubular member in a plug flow manner and injecting sulphur dioxide or a sulphite solution into the solution as it enters the tubular member. When the sulphate solution also contains dissolved selenium (VI) values, the ratio of dissolved selenium (IV) values to dissolved selenium (VI) values is preferably at least 3 to 1.
摘要翻译： 从酸性硫酸铜水溶液中除去溶解的硒IV值的方法包括使溶液以插塞流方式通过管状构件，并且当溶液进入管状构件时将二氧化硫或亚硫酸盐溶液注入溶液中。 当硫酸盐溶液也含有溶解的硒（VI）值时，溶解的硒（IV）值与溶解的硒（VI）值的比优选为至少3:1。
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公开(公告)号：US4571262A
公开(公告)日：1986-02-18
申请号：US710738
申请日：1985-03-11
CPC分类号： C01B19/004 , C01B19/007 , C01B19/008 , C22B11/04 , C22B15/0071 , C22B15/0089 , C22B23/043 , C01P2006/80 , Y02P10/236
摘要： A process for separately recovering platinum group metal values, nickel values and copper from nickel-copper-iron sulphidic matte containing platinum group metals includes leaching ground matte at atmospheric pressure in acidic nickel-copper sulphate solution at a temperature in the range of from about 75.degree. to about 105.degree. C. and at a pH below about 4 initially under oxidizing conditions and subsequently under neutral or non-oxidizing conditions to cause dissolution of nickel and iron, precipitation of copper as a copper sulphide and precipitation of dissolved platinum group metals. The copper, nickel and platinum group metal containing solids are separated from the nickel and iron containing sulphate solution and are leached in acidic nickel-copper sulphate solution under pressurized oxidizing conditions at a temperature of from about 120.degree. to about 180.degree. C. to cause dissolution of nickel and copper with minor dissolution of platinum group metals. The platinum group metal containing solids are separated from the nickel and copper containing sulphate solution, and copper is electrowon from the nickel and copper containing sulphate solution under conditions to cause cathodic deposition of copper without significant deposition of nickel. Spent nickel and copper containing electrolyte solution which also contains minor amounts of dissolved platinum group metals is recycled to the atmospheric leach and pressure leaching steps.
摘要翻译： 在含有铂族金属的镍 - 铜 - 铁硫化物锍中单独回收铂族金属值，镍值和铜的方法包括在大气压下在酸性硫酸镍 - 硫酸铜溶液中浸出磨碎的锍，温度范围为约75 温度至约105℃，pH低于约4，最初在氧化条件下，随后在中性或非氧化条件下引起镍和铁的溶解，铜作为硫化铜沉淀并沉淀溶解的铂族金属。 将含铜，镍和铂族金属的固体与含镍和铁的硫酸盐溶液分离，并在约120℃至约180℃的温度下在加压氧化条件下在酸性硫酸镍 - 硫酸盐溶液中浸出，导致 镍和铜的溶解与铂族金属的轻微溶解。 将含有铂族金属的固体与含有镍和铜的硫酸盐溶液分离，铜在含有镍和铜的硫酸盐溶液的电解下，在不会显着沉积镍的条件下引起铜的阴极沉积。 还含有少量溶解的铂族金属的含有镍和铜的电解质溶液被循环到大气浸出和压力浸出步骤中。
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3.发明授权Method for removing arsenic from copper and/or nickel bearing aqueous acidic solutions by solvent extraction 失效通过溶剂萃取从含铜和/或含镍酸性水溶液中除去砷的方法
公开(公告)号：US4115512A
公开(公告)日：1978-09-19
申请号：US747104
申请日：1976-12-03
申请人： Derek G. E. Kerfoot
发明人： Derek G. E. Kerfoot
CPC分类号： C22B3/0068 , C01G28/001 , C22B3/0095 , Y02P10/234
摘要： A method is disclosed for removing arsenic by solvent extraction from a copper and/or nickel bearing aqueous solution containing about 100 to 600 gpl sulphuric acid. The method comprises contacting the solution with an organic solution consisting of about 5 to 80% by volume of tributylphosphate in an organic diluent, and subsequently stripping the arsenic from the loaded organic solution with a suitable stripping agent. Particularly, when the sulphuric acid concentration in the aqueous solution is lower than 300 gpl, the organic solution advantageously comprises up to about 15% of a quaternary ammonium reagent. Preferred quaternary ammonium reagents are tricaprylmethyl ammonium chloride and mixtures of tri-C.sub.8 -C.sub.10 methylammonium chlorides.
摘要翻译： 公开了一种通过溶剂萃取从含有约100至600gp1硫酸的含铜和/或含镍水溶液中除去砷的方法。 该方法包括使有机溶液与有机溶液接触，所述有机溶液由有机稀释剂中约5-80体积％的磷酸三丁酯组成，随后用合适的剥离剂从负载的有机溶液中除去砷。 特别地，当水溶液中的硫酸浓度低于300gp1时，有机溶液有利地包含高达约15％的季铵试剂。 优选的季铵试剂是三辛基甲基氯化铵和三-C 8 -C 10甲基铵氯化物的混合物。
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公开(公告)号：US4006269A
公开(公告)日：1977-02-01
申请号：US528210
申请日：1974-11-29
申请人： Derek G. E. Kerfoot
发明人： Derek G. E. Kerfoot
IPC分类号： C03C17/10 , C04B41/51 , C04B41/88 , C23C18/16 , C23C18/18 , C23C18/28 , H05K3/18 , B05D3/06 , B05D5/12
CPC分类号： H05K3/187 , C03C17/10 , C04B41/51 , C04B41/5111 , C04B41/5144 , C04B41/88 , C23C18/1608 , C23C18/1612 , C23C18/34 , C23C18/40 , H05K3/185
摘要： A method for sensitizing a substrate of non-conductive material for the deposition thereon of a conductive film of copper or nickel comprises the steps of applying to the substrate a substance which can photochemically abstract a hydrogen atom from a hydrogen donor in the presence of a suitable solvent, and subsequently immersing the sensitized substrate in a solution containing certain metal ions such as copper, nickel or silver, and simultaneously exposing the sensitized substrate to radiation from an ultraviolet light source.
摘要翻译： 用于使用于其上沉积铜或镍的导电膜的非导电材料的基底敏化的方法包括以下步骤：在适当的位置上向基底施加能够从氢供体上光电取代氢原子的物质 溶剂，然后将敏化的基材浸入含有某些金属离子如铜，镍或银的溶液中，同时使敏化的基材暴露于紫外光源的辐射。
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公开(公告)号：US4374808A
公开(公告)日：1983-02-22
申请号：US391807
申请日：1982-06-24
CPC分类号： C01B19/007 , C01G3/10 , C01G53/00 , C22B15/0089 , C22B15/0093 , C22B23/0461 , C22B3/44 , C01P2006/80 , Y02P10/234 , Y02P10/236
摘要： Selenium (IV) and selenium (VI) are removed from acidic copper-nickel sulphate solutions in a two-stage process by adjusting and maintaining the sulphuric acid content of the solution in a range of 10 to 50 g/L and, in a first stage, contacting the solution with sulphur dioxide or a sulphite-containing solution at an elevated temperature in the range of about 140.degree. to 175.degree. C. and, in a second stage, maintaining the said solution at an elevated temperature in the range of about 140.degree. to 200.degree. C. and pressure within the range of about 400 to 1750 kPa in an essentially oxygen-free atmosphere for a sufficient retention time to reduce and precipitate selenium (VI) as cuprous selenide.
摘要翻译： 通过调节和维持溶液的硫酸含量在10至50g / L的范围内，在两步法中从酸性硫酸铜 - 硫酸镍溶液中除去硒（Ⅳ）和硒（Ⅵ） 在约140℃至175℃的升高的温度下将溶液与二氧化硫或含亚硫酸盐的溶液接触，并且在第二阶段中，将所述溶液保持在约 140℃至200℃，压力在约400至1750kPa的范围内，在基本上不含氧的气氛中保持足够的保留时间以减少和沉淀硒（VI）作为亚硒酸铜。
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公开(公告)号：US4132667A
公开(公告)日：1979-01-02
申请号：US839564
申请日：1977-10-05
申请人： Derek G. E. Kerfoot
发明人： Derek G. E. Kerfoot
CPC分类号： C09D5/084 , C09C1/0003 , C09C1/0081 , C09C1/0084 , C09C1/0087 , C01P2002/72 , C01P2004/84
摘要： A novel group of corrosion inhibiting pigments has been discovered, which is based on zinc molybdate compounds selected from sodium zinc molybdate, potassium zinc molybdate, ammonium zinc molybdate and mixtures thereof, combined with a suitable carrier, so that the proportion of the zinc molybdate compound is such that the Mo content in the pigment is between about 1 and 30% by weight. Such pigments can be prepared in situ by several methods, such as a double decomposition reaction of sodium, potassium or ammonium molybdate and a solution containing dissolved zinc ion, or an addition of an appropriate acid to zinc oxide dispersed in sodium, potassium or ammonium molybdate solution, or an addition of zinc oxide to a solution which comprises molybdic oxide dissolved in an aqueous solution of sodium, potassium or ammonium molybdate. All these methods are simple, economic and lead to non-toxic pigments of essentially white colour, which have anti-corrosive properties comparable to, or better than, those of zinc yellow and other commercially available corrosion inhibiting pigments.
摘要翻译： 已经发现了一组新的腐蚀抑制颜料，其基于选自钼酸锌锌，钼酸锌锌，钼酸铵锌及其混合物的钼酸锌化合物，并与合适的载体结合，使得钼酸锌化合物 使得颜料中的Mo含量在约1至30重量％之间。 这样的颜料可以通过几种方法原位制备，例如钼酸钠，钼酸钾或钼酸铵的双重分解反应和含有溶解的锌离子的溶液，或向分散在钼酸钠，钾或铵的氧化锌中加入适当的酸 溶液或氧化锌加入到溶解在钼酸钠，钾或铵的水溶液中的氧化钼的溶液中。 所有这些方法都是简单的，经济的，并且导致基本上为白色的无毒颜料，其具有与锌黄和其它商业上可获得的腐蚀抑制颜料相当或优于其的抗腐蚀性能。
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公开(公告)号：US5468281A
公开(公告)日：1995-11-21
申请号：US335701
申请日：1994-11-17
申请人： Derek G. E. Kerfoot
发明人： Derek G. E. Kerfoot
CPC分类号： C22B23/0492 , C22B23/0446 , C22B3/14 , Y02P10/234
摘要： A process is disclosed for separating cobalt in the form of cobalt (III) hexammine sulphate from an aqueous solution containing cobalt (III) hexammine sulphate and nickel (II) hexammine sulphate comprising adding ammonium sulphate to provide an effective amount of ammonium sulphate, saturating the solution with an effective amount of ammonia at a temperature whereby the triple salt of cobalt (III) hexammine sulphate, nickel (III) hexammine sulphate and ammonium sulphate is precipitated, recovering the precipitated triple salt from the solution, and repulping the triple salt with an effective amount of water or aqueous ammonia solution to selectively leach nickel (II) hexammine sulphate to produce a crystalline cobalt (III) hexammine sulphate with a cobalt: nickel ratio of at least 100:1.
摘要翻译： PCT No.PCT / CA93 / 00213 Sec。 371日期：1994年11月17日 102（e）日期1994年11月17日PCT提交1993年5月19日PCT公布。 公开号WO93 / 23578 日本公开了一种用于从含有硫酸钴（III）和硫酸镍（II）的硫酸镍的水溶液中分离硫酸钴（III）形式的钴的方法，其包括加入硫酸铵以提供有效的 在硫酸钴（III）硫酸镍（III），硫酸镍（III）和硫酸铵的三重盐沉淀的温度下，从溶液中回收沉淀的三重盐，从而使有效量的氨饱和溶液， 并用有效量的水或氨水溶液重新调整三重盐，以选择性地浸提硫酸镍（II）硫酸亚硫酸盐以产生钴：镍比为至少100:1的结晶的硫酸钴（III）。
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公开(公告)号：US5344479A
公开(公告)日：1994-09-06
申请号：US29513
申请日：1993-03-11
申请人： Derek G. E. Kerfoot , Rein Raudsepp
发明人： Derek G. E. Kerfoot , Rein Raudsepp
CPC分类号： C22B23/043 , C22B15/0071 , C22B3/08 , Y02P10/234 , Y02P10/236
摘要： A process is disclosed for separating and recovering nickel and copper values from a nickel-copper matte which may contain iron and arsenic. Finely divided nickel-copper matte is leached in aqueous sulphuric acid solution under oxidizing conditions at atmospheric pressure and at a minimum temperature of about 80.degree. C. to selectively leach nickel from the matte to produce a nickel sulphate solution having a final pH in the range of about 4.0 to 6.5, preferably about 6.5, and to produce a copper-rich sulphide residue. The copper-rich sulphide residue is separated from the nickel sulphate solution and leached in a closed reaction vessel at a minimum temperature of about 120.degree. C. under a non-oxidizing atmosphere in a sulphuric acid solution containing an effective amount of copper and sulphuric acid to provide a terminal concentration of at least about 2 g/L Cu.sup.2+ and at least about 20 g/L sulphuric acid to produce a nickel sulphate solution containing any iron and arsenic and to produce a low nickel copper sulphide product essentially free of iron and arsenic.
摘要翻译： 公开了从可能含有铁和砷的镍铜锍分离和回收镍和铜的方法。 在大气压和大约80℃的最低温度的氧化条件下，细碎的镍铜锍在硫酸水溶液中浸出，以从锍中选择性浸出镍，以产生最终pH范围内的硫酸镍溶液 约4.0至6.5，优选约6.5，并产生富铜硫化物残余物。 将富含铜的硫化物残余物与硫酸镍溶液分离，并在非氧化性气氛下，在含有效量的铜和硫酸的硫酸溶液中，在约120℃的最低温度下，在封闭的反应容器中浸出 以提供至少约2g / L Cu2 +和至少约20g / L硫酸的终浓度以产生含有任何铁和砷的硫酸镍溶液并产生基本上不含铁和砷的低镍硫化铜产品 。
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公开(公告)号：US4338168A
公开(公告)日：1982-07-06
申请号：US233516
申请日：1981-02-11
CPC分类号： C22B15/0071 , C22B15/0089 , Y02P10/236
摘要： A method is provided for recovering copper values from a copper-bearing hematite residue in a single stage. It comprises leaching the residue in an aqueous sulphuric acid solution in the presence of ammonium, sodium or potassium ions, at a temperature between about 80.degree. C. and the boiling point of the solution so that copper values are dissolved while iron is precipitated as jarosite. The method is particularly suitable for the treatment of residues resulting from an oxidizing pressure leach of copper concentrates.
摘要翻译： 提供了在单一阶段从含铜赤铁矿残渣中回收铜值的方法。 它包括在铵，钠或钾离子存在下，在约80℃和溶液沸点之间的硫酸水溶液中浸出残留物，使铜溶解，而铁作为黄钇铁矿沉淀 。 该方法特别适用于处理由浓缩铜精矿的氧化压力浸出产生的残留物。
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10.发明授权Hydrometallurgical production of technical grade molybdic oxide from molybdenite concentrates 失效来自辉钼矿精矿的工业级氧化钼的湿法冶金生产
公开(公告)号：US3988418A
公开(公告)日：1976-10-26
申请号：US605443
申请日：1975-08-18
CPC分类号： C22B34/34 , Y02P10/234
摘要： An improved hydrometallurgical method is provided for producing technical grade molybdic oxide from molybdenite concentrates. According to this method, the molybdenite concentrates are leached in an acid medium having a nitric acid concentration between about 25 gpl and about 50 gpl and an initial sulphuric acid concentration of nil to about 750 gpl, under oxygen pressure of about 100 - 250 psig and at a temperature above 115.degree. C so as to produce technical grade molybdic oxide having not more than 0.1% sulphur. Then a liquid-solid separation of the reaction mixture is effected and the obtained leach liquor is recycled back to the leaching stage optionally after partial neutralization with a basic reagent. The solid is washed and recovered as technical grade molybdic oxide.This invention relates to a novel method of producing hydrometallurgically technical grade molybdic oxide from molybdenite concentrates.Technical molybdic oxide is usually prepared commercially by roasting molybdenum disulphide concentrates in air at temperatures of 550.degree.-600.degree. C. These molybdenum disulphide concentrates commonly contain minor amounts of silica and iron, copper and lead sulphides which are oxidized and report as impurities in the molybdic oxide product, and traces of rhenium sulphide which are also oxidized and partially volatilized in the roasting process. The volatilized rhenium can be recovered from the flue gases by known scrubbing techniques. Due to more and more stringent pollution controls, however, these roasting techniques, which produce great amounts of polluting gases, have now become unsatisfactory.It is also known that molybdic oxide can be prepared from the molybdic acid obtained by leaching molybdenum containing minerals with nitric acid in a sealed vessel under increased partial pressures of oxygen and at elevated temperatures, using less than the theoretical concentration of nitric acid. This has been disclosed, for example, by G. Bjorling and G. A. Kolta in Intern. Mineral Process. Congr., Tech. Papers, 7th, New York City, 1964 -- 127-38 and J. Chem. U.A.R. 12, No. 3, 423-435 (1969).In the leaching of molybdenum minerals with nitric acid, molybdenum disulphide is oxidized to molybdic acid and sulphuric acid, according to the following equation:MoS.sub.2 + 6HNO.sub.3 .fwdarw. H.sub.2 MoO.sub.4 + 2H.sub.2 SO.sub.4 + 6NOhowever, since molybdic acid is only soluble in the acid medium to a limited extent, precipitation of a large part of the molybdic acid occurs during the course of the oxidation process, and this precipitate can be filtered off from the solution, together with siliceous gangue, and can be used directly as technical grade molybdic acid or, following a simple calcining treatment, as technical grade molybdic oxide. If the reaction is carried out under sufficient pressure and at temperatures in excess of 115.degree. C, the molybdic acid is dehydrated in situ to molybdic oxide, so that technical molybdic oxide can be obtained directly.The major disadvantage of such processes, which has rendered them uneconomic in the past, is discussed in Canadian Pat. No. 905,641 issued July 25, 1972 to Bengt O. P. Mollerstedt and Karl-Erik Backius. It lies in the difficulty of recovering the dissolved molybdic acid from the leach liquor which also contains rhenium, copper, iron and other impurities in addition to sulphuric acid, and unconsumed nitric acid. The molybdenum content of this solution can represent as much as 20 to 25% by weight of the molybdenum content of the feed material.It is known that such solutions can be treated by solvent extraction and ion exchange techniques to separate the molybdenum and rhenium values from the acid leach liquor. One such method is described in U.S. Pat. No. 3,739,057 of June 12, 1973 issued to Ellsworth W. Daugherty, Albert E. Erhard and James L. Drobnick. In this patent there is described a process using in the leaching stage a very low nitric acid concentration of between 10 and 25 gpl while controlling the temperature of the gas phase reaction zone in the pressure vessel, and then recovering from the obtained solution the molybdenum and rhenium values with an amine or quaternary ammonium type extractant. This is followed by stripping the molybdenum and rhenium values from the solvent with ammonium hydroxide, separating the rhenium from the molybdenum in the stripping solution with a quaternary ammonium type extractant, and finally recovering the molybdenum and rhenium by conventional techniques. However, it will be appreciated that such a process is relatively difficult and costly since it involves the treatment by solvent extraction of the entire liquid component of the reaction mixture, which is certainly a complex and expensive operation. In addition, nitric acid has a deleterious effect on molybdenum extraction and consequently the nitric acid content in the liquor passing to the solvent extraction stage must be kept very low. This is probably the reason for which very low concentrations of nitric acid are used according to U.S. Pat. No. 3,739,057 in spite of the fact that they will obviously result in lower conversions to molybdic oxide. Furthermore, the by-product sulphuric acid from such processes is relatively impure and does not find a ready market.It is therefore the principal object of this invention to provide a novel hydrometallurgical method for the transformation of molybdenite concentrates into technical grade molybdic oxide which would obviate or substantially diminish the disadvantages of the presently known hydrometallurgical processes.It is a further object of this invention to provide a more economical method of hydrometallurgical treatment of molybdenite concentrates to produce directly technical grade molybdic oxide.Other objects and advantages of the present invention will be made obvious from the following more detailed description:Thus, it has been surprisingly found according to the present invention that the yield of technical grade molybdic oxide which can be recovered directly by filtration from the nitric acid leach process can be increased from about 75-85% to at least 95% by recycling and reusing the leach liquor (after filtering off the molybdic oxide product) to leach a further quantity of molybdenite concentrate. Since the leaching medium is already saturated with molybdic acid, the precipitation of molybdic oxide from the molybdenite feed, in the second and subsequent leach steps, becomes substantially quantitative.The method of the present invention for producing hydrometallurgically technical grade molybdic oxide from molybdenite concentrates basically comprises:a. leaching the molybdenite concentrate in an acid medium having a nitric acid concentration between about 25 gpl and about 50 gpl and an initial sulphuric acid concentration of nil to about 750 gpl, under oxygen pressure of about 100 to 250 psig. and at a temperature above 115.degree. C so as to produce technical grade molybdic oxide having not more than 0.1% sulphur;b. effecting a liquid-solid separation of the resultant reaction mixture to separate the leach liquor from the solids;c. recycling the leach liquor from the liquid-solid separation step (b) to the leaching step (a);d. washing the solids of the liquid-solid separation step (b) and recovering the technical grade molybdic oxide; ande. repeating leaching step (a) with recycled leach liquor from step (c) after adjustment of the nitric acid and sulphuric acid concentrations.It was found that in such leach liquor recycling method, a nitric acid concentration below about 25 gpl (about 0.45 lbs. of nitric acid per lb. of quadravalent molybdenum in the molybdenite concentrate) would be insufficient to give satisfactory conversion to technical grade molybdic oxide and concentrations above 50 gpl (about 0.90 lb. of HNO.sub.3 per lb. of quadravalent molybdenum in the molybdenite concentrate) would be unnecessary because they would involve useless recycling or loss of nitric acid in wash water and would render the reaction control more difficult. The initial concentration of sulphuric acid in the leach liquor could be nil or it could be adjusted to a level of up to about 750 gpl, preferably up to 400 gpl, and it should be maintained at such level (referring to pure sulphuric acid) during the entire operation in order to prevent excessive dissolution of the molybdic oxide product. In accordance with the present invention the sulphuric acid concentration can readily be maintained at the desired level. In view of the fact that during the liquid-solid separation step, which is carried out after the leaching operation, (e.g. by filtration), the moist solid phase will retain a portion of the liquor of about 10 to 15%, this portion of the liquor removed with the solids will obviously contain a good proportion of sulphuric acid which is thus eliminated from the recycled leach liquor and replaced by an equivalent amount of water, thereby continuously maintaining the sulphuric acid concentration in the system at the desired value. It will be apparent that it is unnecessary to remove more liquor than about 15% during the liquid-solid separation in order to maintain the sulphuric acid concentration at the desired level, but if, for some reason, this became desirable one could easily remove some additional liquor at this stage and replace it by water or the like.Optionally, the sulphuric acid concentration can be reduced by partial neutralization of the liquor after liquid-solid separation and washing, but prior to recycling. Such partial neutralization can be carried out with a calcium reagent such as CaO, Ca(OH).sub.2 or CaCO.sub.3 until the pH value of the liquor reaches the isoelectric point of molybdic acid (pH .congruent. 0.9). Up to that point, the dissolved molybdenum is present in solution as cationic molybdenyl species which remain in solution while calcium sulphate precipitates as gypsum. consequently the loss of molybdenum to the gypsum precipitate during such partial neutralization is negligible. The preferred pH limit for this operation is about 0.7.Moreover, since calcium perrhenate is soluble in aqueous acid solutions, there is little possibility of rhenium co-precipitating with the calcium sulphate, so that repeated recycling of the leach solution leads to progressive enrichment of the solution with rhenium. By this technique rhenium can be recovered economically from concentrates of low rhenium content, since progressive enrichment of the leach solutions in rhenium is thereby achieved. A fraction of such enriched solution (generally less than 10%) can thus be removed during each cycle, from which rhenium and molybdenum can be separated by established solvent extraction or liquid ion exchange techniques, and the rhenium can be separated from the molybdenum by sorption on activated charcoal or by an ion exchange process.This procedure, with the partial neutralization step, gives even higher direct recovery yields than without partial neutralization, namely of the order of 98%.Furthermore, it was found that the leaching operation in accordance with the novel method of this invention should be effected under oxygen pressure of about 100 to 250 psig and at a temperature above 115.degree. C and preferably between 120.degree. and 160.degree. C for a period of time sufficient to effect the required conversion to produce molybdic oxide having not more than 0.1% sulphur. In this regard, it is well known that technical grade MoO.sub.3 should contain a maximum of 0.1% sulphur. It was found that only conversions of the order of about 99.5% or more give such low sulphur contents in the final technical MoO.sub.3 product which is directly produced by this method.It should also be noted that the leaching operation in accordance with this invention is carried out in a pressurized vessel or autoclave and, since the reaction is exothermic, the slurry which is being leached is cooled in the autoclave to maintain the temperature of said slurry between about 120.degree. and 160.degree. C. It has actually been found that there is essentially no temperature differential between the slurry and the gases in the upper part of the autoclave, indicating that the exothermic regeneration of nitric acid occurs in the slurry itself in accordance with this invention. There is thus no need for additionally controlling the temperature of the gas phase within the autoclave by providing complex means in such gas phase as this is done, for instance, in U.S. Pat. No. 3,739,057. The method of the present invention can be carried out in a regular autoclave or pressure vessel without any special additions or transformations thereof. However, the vessel or autoclave should preferably be so designed as to achieve optimum rates of oxygen transfer into the slurry.The required conversion to achieve a sulphur control of 0.1% or less has usually been obtained, under operating conditions of this invention, within about 120 to 240 minutes. In many instances this conversion was 99.9%, which is practically quantitative.The preferred operational leaching conditions in accordance with this invention are as follows:______________________________________ initial nitric acid concentration about 25-40 gpl; initial sulphuric acid concentration below about 400 gpl; temperature about 120-160.degree. C; oxygen pressure about 150-200 psig; leaching time about 180-240 minutes. ______________________________________ The consumption of nitric acid under such process conditions is of the order of 5g/100g of molybdenite treated, which is certainly very economical.The other conditions of the leaching operation are generally conventional. Thus, the leaching slurry may contain a suitable proportion of solids, but is usually carried out at about 10% solids. The particle size of the concentrate treated should be suitable to provide satisfactory contact surface area for the leaching operation which is carried out under agitation. The preferred particle size is about 50-80% minus 325 mesh.After separation of the liquor from the solid reaction product of the leaching step, the obtained wet solids are washed to yield directly the technical grade molybdic oxide, which contains less than 0.1% sulphur and can be marketed as such. This product, although entirely satisfactory, has however a greyish colour rather than the usual yellow colour of the roasted molybdic oxide. This greyish colour is believed to be due to a slight surface reduction of molybdic oxide during drying of the product. If desired, the greyish product can be transformed into the usual yellow technical grade MoO.sub.3, by optionally calcining it at a temperature of up to about 600.degree. C. Obviously, since the molybdic oxide product has a sulphur content of less than 0.1%, such calcining operation produces essentially no objectionable SO.sub.2 polluting gases.The wash waters will contain some recoverable metal values, particularly some molybdenum and rhenium. These recoverable metal values can be recovered from the wash waters by the usual solvent extraction or liquid ion exchange techniques and the rhenium can be separated from the molybdenum by sorption on activated charcoal or by an ion exchange process. It will be appreciated that due to the fact that only a small portion of the overall leaching solution will be so treated at a time (up to about 20%), the solvent extraction or ion exchange treatment will be much simplified and will require much smaller investment for the construction, reagent inventory and maintenance of the solvent extraction or ion exchange systems necessary for such treatments. Furthermore, it will be appreciated that repeated recycling of the leach solution will lead to progressive enrichment of the solution with rhenium and therefore rhenium concentrations will be higher than usual and thus it can be more readily and more economically recovered by conventional techniques. However, if the initial molybdenite concentrate is such that the amount of rhenium is very low and unimportant in the overall economy of the process, it need not be recovered separately from molybdenum.It will also be appreciated that other metal values present in the molybdenum concentrate will dissolve to some extent in the leach liquor so that recycling will lead to a progressive increase in the concentration of such metals. However, the removal of a small fraction of the liquor with the solids, in each cycle of the operation, as already described above, either with or without partial neutralization, will enable to control the concentration of these impurities to a satisfactory degree.After recovery of the recoverable metal values from the wash waters, the wash waters, which are acidic in nature, can be neutralized, usually with calcium oxide, calcium hydroxide or calcium carbonate, and discarded.
摘要翻译： 提供了一种改进的湿法冶金方法，用于从辉钼矿精矿生产工业级氧化钼。 根据该方法，将辉钼矿精矿在硝酸浓度约为25gp1至约50gp1，初始硫酸浓度为零至约750gp1，氧气压力为约100-250psig的酸性介质中浸出， 在115℃以上的温度下生产具有不超过0.1％硫的工业级氧化钼。 然后进行反应混合物的液固分离，所获得的浸出液可任选地在用碱性试剂部分中和后循环回到浸出阶段。 将固体洗涤并回收为工业级氧化钼。
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