| Reduction of copper content in the molybdenite concentrate -> Monitor Keywords |
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Reduction of copper content in the molybdenite concentrateRelated Patent Categories: Chemistry Of Inorganic Compounds, Treating Mixture To Obtain Metal Containing Compound, Group Ib Metal (cu, Ag, Or Au), Leaching, Washing, Or Dissolving, Forming Insoluble Substance In Liquid, SulfidingReduction of copper content in the molybdenite concentrate description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20060182674, Reduction of copper content in the molybdenite concentrate. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims benefit of U.S. Provisional Patent Application Ser. No. 60/649,463, filed Feb. 2, 2005, entitled "Reduction of Copper Content in the Molybdenite Concentrate" which is herein incorporated by reference. BACKGROUND [0002] 1. Field of the Invention [0003] Embodiments of the present invention generally relate to a method for mineral purification and more particularly to a method of removing metal sulfides from a molybdenite concentrate. [0004] 2. Description of the Related Art [0005] Copper ore deposits containing copper sulfide minerals, such as chalcopyrite (CuFeS.sub.2), chalcocite (Cu.sub.2S), and bornite (Cu.sub.5FeS.sub.4) may contain minor amounts of molybdenite (MoS.sub.2). Recovery of the valuable molybdenite locked up in the ore is usually performed by a milling operation, followed by several flotation steps. The final molybdenite concentrate usually contains some sulfide minerals, and, to be commercial, the copper sulfide mineral content is typically reduced through a leaching step in which the copper sulfide minerals are dissolved by a leaching solution. [0006] The leaching step is typically performed in a batch operation where the molybdenite concentrate is exposed to the leaching solution in a leaching vessel. After the leaching process, the leaching solution is separated from the molybdenite and is regenerated using chlorine gas. Due to the hazardous nature of the chlorine gas a batch operation with several safety procedures is required during the regenerating process, resulting in high labor, handling, and safety costs. [0007] Accordingly, given the high costs associated with using chlorine gas, the batch operation using chlorine gas is suited to produce small amounts of material. For large amounts of products a continuous mode is normally more economical. In a continuous mode operation, leaching can be performed uninterrupted because the leaching solution is replenished as it is being used. Thus, in a continuous mode operation more molybdenite concentrate can be leached in the same amount of time it takes for leaching in a batch mode operation. [0008] Therefore, a need exists for a method of regenerating a leaching solution for use in a leaching process that is more cost efficient, safer, and can be utilized in a continuous process as well as in a batch process. SUMMARY [0009] The embodiments of the present invention generally provide a method for removing copper minerals from a molybdenite concentrate. One embodiment of the invention provides a method for removing copper sulfides from a molybdenite concentrate by leaching the copper sulfides from the molybdenite concentrate with a leaching solution comprising ferric chloride, removing molybdenite from the leaching solution, introducing an acid into the leaching solution and introducing O.sub.2, O.sub.3, or a combination of both, into the leaching solution. [0010] Another embodiment of the invention provides for obtaining commercial grade molybdenite from a copper ore. The method includes separating a molybdenite concentrate from the copper ore, leaching copper from the molybdenite concentrate with a leaching solution comprising ferric chloride, removing molybdenite from the leaching solution, introducing an acid into the leaching solution and introducing O.sub.2, O.sub.3, or a combination of both, into the leaching solution. [0011] Further embodiments of the invention provide a method for removing copper minerals from a molybdenite concentrate. An exemplary method includes pumping molybdenite concentrate into an autoclave vessel, introducing a solution of Fe(II) ions, Fe(III) ions, or a combination of both, into the autoclave vessel, introducing an acid into the autoclave vessel, introducing O.sub.2, O.sub.3 or a combination of both, into the autoclave vessel, and filtering the molybdenite from a stream exiting the autoclave vessel. [0012] In another embodiment, the invention further provides a method for regenerating ferric chloride in a leaching solution. An exemplary method includes adding a leaching solution comprising Fe(II) ions, Fe(III) ions, or a combination of both, to a mixture of mineral sulfides, and introducing an acid and O.sub.2, O.sub.3 or a combination of both, into the leaching solution. BRIEF DESCRIPTION OF THE DRAWINGS [0013] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. [0014] FIG. 1 is a block diagram for the process of reducing copper content in a molybdenite concentrate at atmospheric pressure. [0015] FIG. 2 is a block diagram for the process of reducing copper content in a molybdenite concentrate under pressure. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0016] FIG. 1 is a block diagram of a system 100 for carrying out a first process, according to one embodiment of the invention. The system 100 includes introducing a molybdenite concentrate into a dissolution vessel 110. The molybdenite concentrate may be stored in a storage tank 120, and typically includes 3-4% w/w copper sulfide minerals, such as, chalcopyrite, chalcocite, bornite, etc. The dissolution vessel 110 is made from a material which will not 35 dissolve or etch in the conditions used during the dissolution process. In one embodiment, the material is glass. A solution of hydrochloric acid is introduced into the dissolution vessel through inlet 140. The concentration of hydrochloric acid is kept between about 0.7 M and about 4.0 M, and more preferably at about 4.0 M, throughout the dissolution process. A stream comprising ferrous chloride, ferric chloride, or a combination of the two, is introduced to the dissolution vessel through inlet 190. Oxygen, ozone, or a combination of the two, is introduced through inlet 130 into the slurry of the dissolution vessel so that gas bubbles are formed in the slurry and solution. The dissolution vessel is kept at temperatures above about 90.degree. C., and more preferably between about 100.degree. C. and about 120.degree. C. The slurry is agitated by stirring methods, such as mechanical agitators which may include a motor, a shaft and an impeller. Depending on the operating parameters and the mineralogical copper species, the leach process is completed after about 10 minutes to about 120 minutes. A stream of the slurry, which has been leached, is then filtered at filter 150 and the filter cake is rinsed with hot water. The water used to rinse the slurry is heated to between about 60.degree. C. and about 100.degree. C., and preferably to about 60.degree. C. The water used for rinsing may also be acidic. The solid separated from the filtrate is dried to a moisture content of less than about 5% w/w and contains molybdenite with a copper content of less than about 0.2% w/w. The filtrate comprising ferrous chloride, ferric chloride, or a combination of both, acid, and dissolved cupric chloride then go through a copper removal process 160 where the copper ions are precipitated as elemental copper out of solution by using iron scrap as a reductant, as shown in Equation 1: Fe+2Cu.sup.2+=Fe.sup.2++Cu Equation 1. [0017] After decopperization, the filtrate contains a higher concentration of iron ions than may be desirable, and thus the filtrate may then go through an optional iron removal process 170 to keep the iron ion concentration around 100 g/L. One way to remove excess iron ions is by reducing the temperature of the filtrate which will decrease the solubility of the iron ions causing precipitation of excess iron chlorides. The filtrate is then heated in preheater 180, and reintroduced into the dissolution vessel 110 through inlet 190. [0018] FIG. 1 describes the continuous process at atmospheric pressure. An alternative embodiment of FIG. 1 is a batch process. In a batch process oxygen, ozone, or a combination of the two, and hydrochloric acid are added to a predetermined volume of acid solution containing ferrous chloride, ferric chloride, or a combination of the two, in dissolution vessel 110. When the ferric chloride concentration reaches a desired level (between about 20 g/L and 100 g/L) molybdenite concentrate is added to vessel 110. During dissolution of copper, only hydrochloric acid is added to vessel 110 in order to maintain an acidity between 1 to 4 M, while ferric chloride concentration decreases with time due to production of ferrous chloride. [0019] In yet an alternative embodiment of FIG. 1, the O.sub.2/O.sub.3 and hydrochloric acid are added to the stream of ferrous chloride, ferric chloride, or a combination of the two, prior to entering the dissolution vessel 110. Continue reading about Reduction of copper content in the molybdenite concentrate... Full patent description for Reduction of copper content in the molybdenite concentrate Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Reduction of copper content in the molybdenite concentrate patent application. ###
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