Extraction of metals from sulphide minerals

FIELD: metallurgy.

SUBSTANCE: method has been elaborated for two-stage dilution of nickel in leaching acid. Suspension of mineral and acid is activated by oxidation. It is performed during T1 time by means of electrolysis or alternatively chemically, by adding for example of oxidating acid to mineral. After activation the suspension is exposed in oxygen-free conditions during T2 time. During T2 time much quicker dilution of sulphide begins; quick decomposition of sulphide gives the possibility to nickel to be diluted and thus leached from mineral. Diluted nickel is extracted from leaching acid for example by electrochemical extraction.

EFFECT: improved process economy.

23 cl, 2 dwg

[001] This invention relates to the extraction leaching of valuable metals such as Nickel, which is found in trace concentrations in sulfide minerals, such as iron-sulfide minerals. The invention is mainly described with regard to Nickel; and if other metals are present in sulfide minerals, probably, they will also be leached. Examples of other precious metals (except Nickel)that can be recovered by the methods described herein, include a group of elements: copper, gold, silver, lead, zinc, molybdenum, cobalt, bismuth, antimony and platinum.

Prior art

[002] the Traces of Nickel are often present in large, easy-to-reach masses of Nickel sulfide and iron sulfide minerals, such as, for example, the existing mass of iron sulfide tailings associated with the operations of producing (including the extraction of Nickel). However, although the source material is more available, extraction of Nickel from this source material up to that time was justified as uneconomical. In addition, there are some readily available, but low-grade Nickel ore from which again was uneconomical to extract Nickel, using traditional methods.

[003] the Aim of the invention is to make it economical to extract Nickel and other prices is a diversified metals which are present in sulfide minerals. Recognized that the invention can be applied in cases where metals are present in small amounts in sulfide minerals, for example, approximately less than 0.15% or so in the case of Nickel and 0.01% in the case of precious metals such as gold. Of course, other technologies can be cost-effective for the extraction of Nickel from sulfide ores, when Nickel is present in amount of about 4% or more, while this technology can be cost-effective at much lower concentrations and, moreover, is not so invasive in the environment. The minerals from which valuable metals can be recovered by methods described here include pyrite, pentlandite, perrott, chalcopyrite, sphalerite, Galena, some sulphosalts of valuable metals and the like.

Background of the invention

[004] a Simple leaching, namely immersion of the source material in acid, not used to make precious metal enter into the solution, or at least not at a commercially feasible rate. When taking oxidation, pestiviruses layers tend to form in sulfide minerals that prevent or inhibit present metals from dissolving.

Some features of the invention

[005] the Amount paten the Noah protection required here, is defined by the attached claims.

[006] it Was recognized that it is possible to increase the speed at which you can get the dissolution of sulfide minerals, avoiding or circumventing the problem of passivation of the mineral.

[007] it Was recognized that the mineral is pyrrhotite iron sulfide is a mineral that can be created for dissolution at high speed under certain circumstances following a special procedure. The procedure is, in essence, is the following:

- dip mineral iron sulfide in the acid (for example, at pH 2), thus forming a suspension;

- delivery of oxidative energy to suspension for activation (partial oxidation) of the mineral;

- stop delivery of oxidative energy to the suspension after a period of time T1;

- allow the suspension to stand for a time T2 when anoxic conditions.

[008] what happens is that, after activation, sulfide mineral passes through a number of phases:

when beginning the activation, there is an immediate, but short-lived rise of dissolving the selected Fe, compounds with sulfur-oxygen bond hydroxide/oxyhydroxide, etc.;

then, in the induction phase, the input activation energy continue. The iron sulfide passes into solution, and varieties of sulphur be formed or placed the military on the particles of the mineral;

- induction phase ends when the sulfide mineral is completely or almost completely activated, and oxidative energy injected continuously;

now the suspension was left to stand under anoxic conditions. Thus, the phase starts fast recovery dissolution. The rate at which the sulfide mineral is now dissolved, by several orders of magnitude faster than during the induction phase;

in conclusion, the dissolution rate decreases. At this stage, typically, more than 85% of the sulfide mineral collapsed. Iron, on the basis of this is present as dissolved Fe++, and part of the sulfur is present as dissolved species sulfur or elemental sulfur. A large part of the sulfur released from the sediment in the form of hydrogen sulfide gas.

[009] These phases are now considering in more detail. During the induction phase is unstable or metastable polysulfides are allocated on until dissolved sulfide particles. Also at this time the iron is subjected to oxidative dissolution, but only slowly, as it diffuses through the layers, rich in sulphur.

[0010] it Was recognized that if the input oxidative energy continued for a long period that could, or could happen, especially with regard to the mineral pyrrhotite, unstable types of polysulfide is Udut to yield stable elemental sulfur and samples of compounds with sulfur-oxygen bond, which will or may form layers around the undissolved particles of sulfide mineral. It was recognized that these resistant layers, if allowed to grow, will largely Passepartout remaining mineral and significantly inhibit further dissolution. Thus, the input oxidative energy must be reduced and, preferably, should be reduced before the unstable or metastable polysulfides are caught in a sustainable forms of sulfur.

[0011] When the input oxidative conditions ceased, it was the end of the induction phase. Phase starts rapid dissolution. Now unstable varieties of polysulfide is subjected to reductive reactions, and this causes a very strong dissolution.

[0012] with regard to rapid dissolution, it can be assumed that during the induction phase, the electrons captured in a metastable positions of the areas of the surface of sulfide crystals. The assumption is that when a negative charge is accumulated to a level that is able to reduce the covalent bond S-S, then the electrons available for dilution sufficient to reduce polysulfide species and a rapid phase. This fast phase can theoretically continue until all of sulfide mineral will not disintegrate. T is m, not less relative to the last stages, pestiviruses layers begin to dominate, and further dissolution is inhibited; although, at least in the case of pyrrhotite, when this happens, typically about 98% of the sulfide were already broken.

[0013] Thus, after a phase of rapid dissolution, in this case 98% of Fe sulfide are now residing in solution in the acid. A number of S is always in solution as soluble species of sulfur, but it is much more S was allocated in the form of gas H₂S.

[0014] Now will be described the effects of the above-mentioned chemical method on the Nickel that is constantly minerals.

[0015] the Nickel, when present in the minerals iron sulfide, is often associated with sulfide minerals pyrrhotite and pentlandite. Nickel pyrrhotite may be present as a solid solution and/or in the form of small prorastanii of pentlandite in sulphide pyrrhotite. It is considered unlikely that the pentlandite has a property as pyrrhotite, which can be created to undergo a phase of rapid dissolution.

[0016] Although, probably, pentlandite, by itself, may not (economically) to be created for the exposure phase of rapid dissolution, it is also likely that when pentlandite is in close proximity to the pyrrhotite and when the pyrrhotite was created, th is would be the phase of rapid dissolution, as described herein, pentlandite can also be made for the release of their metals in solution. In many of the lower parts of the tailings particles pentlandite really physically close to pyrrhotite or pentlandite particles (weakly) are chemically bonded within pyrrhotite. It can be expected that any Nickel in the form of a solid solution within the pyrrhotite is released after the dissolution of pyrrhotite.

[0017] the Nickel itself is not a chemical constituent pure pyrrhotite. Not all of the pyrrhotite has the same iron content, but rather the iron content varies from FeS (Fe=1) to Fe=0,8. In an oxidizing environment FeS disintegrates when it is oxidized to Fe+++ SO₄--. Pyrrhotite at lower inclusions of Fe is oxidized to 0,8Fe++ + SO₄-- + 1,6N+.

[0018] Pentlandite includes Nickel and represents Fe_4.5Ni₄5S₈or, mainly, (Fe,Ni)₉S₈. In minerals, of which Nickel is commercially extracted, pentlandite has a tendency to dominate the presence of sulfide, as laid pentlandite, although always present pyrrhotite. But in the mass of tailings, which contain traces of Nickel species, of which the invention relates, primarily, the Nickel is in the pyrrhotite, with a certain amount of pentlandite in the form of small inclusions, which are captured in the pyrrhotite. (ConECs is, other sulfide minerals are also likely to be present, for example, directly pyrite FeS₂.)

[0019] this, In turn, is a mineral pyrrhotite, which can be created to undergo a phase of rapid dissolution. (However, we cannot say that it would be economically impossible to create a phase of rapid dissolution with any other mineral.) Although pentlandite, usually accompanied by pyrrhotite, this invention should be regarded as being especially beneficial when applied to the tails, which have a comparatively small inclusions of pentlandite in the entire matrix of pyrrhotite, i.e. in which the Nickel pentlandite is in physical close proximity to instant pyrrhotite.

[0020] Thus, although Nickel is constantly in pentlandite, mass tails, which is not dominated by pyrrhotite over pentlandite, would not be suitable for recovery of traces of Nickel in the ways described in this invention, to create a phase of rapid dissolution. Cases where the majority of recovering Nickel is actually inside the crystals of pyrrhotite, of course, will be very convenient for the extraction of Nickel in the ways described here.

[0021] it Was recognized that when the methods as described herein, is performed at suitable tails, up to 70% or is more Nickel in the tails can be leaching in acid. Considering the billions of existing tonnes of tailings containing about 1% Nickel, 70% actually represent many millions of tons of very accessible Nickel.

[0022] once the Nickel is leached in acid - along with many varieties of Fe and S, which also fall into the solution, of course - can be deployed usual way of extracting Nickel from acid.

[0023] the Procedure described here for tailings containing Nickel, can also be used for Nickel ore of low quality or concentrates of Nickel ores. Procedures may also be applicable to other metallofullerenes tails and their corresponding low-grade ores or concentrates. It was recognized that the extraction of precious metals by the procedures described herein are particularly suitable for the extraction of Nickel from pre-existing lower layers of sulfide tailings.

Preferred embodiments of the

[0024] Next will be described the technology with reference to the accompanying figures, in which:

Figure 1 is a diagram showing some details of the equipment adapted to maintain some reactions, as described here.

Figure 2 is a chart showing the equipment of Figure 1, are combined in a complete cycle.

[0025] it is Recognized that, in order to be possible leaching Nickel from the tailings Sul is IDA iron (pyrrhotite), this is for the procedures described here should be used, that will create a fast decay of pyrrhotite. It is recognized that minerals are pyrrhotite dissolved, (physically or chemically) captured the Nickel will also be released and will be part of the solution in the leaching acid.

[0026] When designing a system for leaching Nickel from the sediment sulfide minerals in the acid developer must establish the way the first activation of the mineral at the time T1. This is implemented by creating oxidizing environment, for example, classification of sulfide mineral as the electrolyte of an electrolytic cell, for example, by the method discussed below. After time T1 the input energy stopped, and now the developer provides the vigil of the suspension for an additional period of time T2 in an oxygen-free position. After that, the Nickel dissolved in the acid, whence it can be removed by traditional technologies.

[0027] This procedure, if done properly, creates a phase of relatively rapid dissolution of pyrrhotite. It was recognized that during this phase of rapid dissolution (T2) Nickel is also released, and Nickel is also included in the solution in acid.

[0028] Implemented electrolytic, initial or induction phase involves activating (input electric power) suspension, including the surrounding mass of source material, in this case, the sulfide tailings in cleaners containing hydrochloride acid. Sufficient acid was included in the suspension so that the suspension has a pH of about two or less. Enough (liquid) acid is also included, so that the physical consistency and coherence mist are that contribute to the adjustable suspension. This occurs when a lower ratio of solid/liquid (wt./weight), than about 1/1. Mineral, preferably, should be mainly in the form of small particles having a grain size less than 250 microns.

[0029] one would expect that the sulphide particles larger than this will not be or will not be subjected to the phase of rapid dissolution, as described here, within any such appropriate time frame. (In appropriate time frames will be visible all the Nickel, which can be dissolved in about an hour and, of course, less than half a day from the beginning of the phase of rapid dissolution.

[0030] figure 1 is a suspension was placed in a reactor or sealing the vessel 21, in which the activation is carried out by means of electrolysis. The bottom of the reactor 21 includes an anode plate 23, and a cathode provided in the form of a suspended ring 25. These components are arranged so that during operation, the cathode 25 was immersed in a suspension. Mechanized stirrer 27 aimed at eliminating differences, gradie the tov concentration throughout the mass of sediment that maximizes the differences and gradients at the electrodes. Current is supplied to the electrodes from a source of DC power 29.

[0031] the Input electrochemical energy aimed at the partial oxidation of sulfide minerals, and, thus, maintaining the formation of metastable species polysulfide actually activates the mineral. Preferred is a relatively low current density, i.e. preferably less than about one hundred amperes per square meter conductive electrode to maintain the required oxidation reactions, in order to avoid, for example, deposition of metals on the cathode and to avoid reformation of secondary sulfide mineral.

[0032] once the input energy is stopped, for example, after the time T1 (induction phase) and during time T2 (phase rapid dissolution), the suspension should not be exposed to air or other oxidizing agents. Oxidation, if it occurred, could transform the metastable polysulfides in stable sulfur, which, as explained, could asseverate not yet dissolved mineral and to inhibit the reaction of recovery that support the way rapid dissolution.

[0033] Thus, the activated suspension need to keep under anoxic conditions during the period of rapid dissolution T2. You can take the Dean stage to support the implementation of anoxic conditions for holding suspended during time T2 of the phase of rapid dissolution in the same vessel, which they had occupied during the time T1 phase induction or activation. Specific oxidation would be very easy to happen if a suspension is transferred from one vessel to another. However, developers could define such a transfer for reasons of production.

[0034] Some small sorokiniana, once activated, could be sustained, but then the phase of rapid dissolution may be delayed. Of reduction reaction, which lead to rapid dissolution may not occur until such additional oxidation will not be weakened. The smaller the number sverhokislennoy elemental sulfur, the shorter the waiting time that must elapse before a phase of rapid dissolution that can be done. As discussed, too much oxidation of sulfide leaves a lot of the resulting sulfur in the elemental form, which passivates the remaining sulfide mineral and inhibits the phase of rapid dissolution at all from the appearance.

[0035] In figure 1, the anode plate of titanium or niobium coated with diamond doped with boron (BDD). Material BDD is very stable and has a high overpotential, 2.2 volts (SHE (standard hydrogen electrode)), for oxygen. It was recognized that the material BDD can be very effective in the oxidation applications. BDD is a PR is pactically, but other materials can be used in the anode, if they have a high oxygen overpotential (more than 1.8 V SHE).

[0036] At least in the case of activation of the electrolysis, the amount of input energy required for the activation step can be estimated (from published data) from about twenty kilojoules per mole of sulfide mineral to approximately one hundred kJ/mol. It will be understood that this range is not expressed as boundary changes; rather, different requirements for power go with a variety of minerals, mineralogical characteristics, densities, etc. as are found in different sources of minerals. Each download sulfide mineral from the same source tails, such as would be expected, has the same requirements of energy within small boundaries.

[0037] an example of a typical full hydrometallurgical cycle shown in figure 2. The tails of the source material 30 is introduced into the vessel for electrolysis 21. Cleaners containing hydrochloride acid introduced into the vessel 21 from the tank for acid 32. In scheme 2 suspension, activated in the vessel 21, moved in anoxic vessel 30, where it was closed and left in anoxic conditions during phases of rapid dissolution.

[0038] As an alternative to activation by electrolysis, oxidative activation of sulphide minerals can conclude x is macheski, as will be described.

[0039] Now sulfide mineral was placed in the activation vessel 21, along with enough water to create a mist that can be easily mixed by the mixer 27. As soon as the suspension is thoroughly mixed by a mixer, then suitable acid introduced into a suspension.

[0040] Suitable oxidizing acids include sulfuric acid, perchloro acid and the like. Cleaners containing hydrochloride acid has rejuvenating properties, however, Hcl can be used with iron sulfide minerals (in particular, weathered tails), because it is formed ferric chloride, which is a strong oxidizing agent.

[0041] a highly Concentrated acid is introduced under pressure, i.e. quickly, in suspension in the activation vessel. Introduction thus acid in aqueous suspension causes an exothermic effect, and the generated heat is used for heating the particulate and acid. For effective activation temperature of the suspension should be raised to at least approximately 40°C in the case of acid Hcl, and at least about 50°C for oxidizing acids. Professionals must ensure that the temperature does not approach the boiling point of any liquid components of the suspension, as it could or could interrupt method.

[0042] In many cases the heat produced by the introduction of acid sufficient what about the support and the end of the activation method. However, the prudent developer also defines convenience for heat activation of the vessel if the additional introduction of heat could be necessary.

[0043] With chemical oxidation, as by electrolytic oxidation, the same vessel can be used for anoxic phase rapid dissolution of the vessel 21, which is used for phase induction or activation, or could be a separate anoxic vessel 30.

[0044] After the activation period T1 and the period of rapid dissolution T2 now treated slurry released from anoxic vessel 30 through the separator solids/liquid 34 from which the fluid passes to the position of the extraction 36 and from which such undissolved solids that remain, move to remove to 38. Not shown in figure 2 is the position for collecting gas of hydrogen sulfide, which is produced in the anoxic reactor.

[0045] the Position of the extraction 36 may be of a standard design. Liquid acid containing dissolved metals is 40. Liquid acid, now with remote dissolved metals, is the capacity for acid 32, for reuse in the method. New acid for dilution, if necessary, add 43. The position of the extraction 36 includes a position electrochemical allocation 45, in which R is stvorennya solids are caused by sediment. Solid metal collected in the storage 47.

[0046] In the laboratory the mass of tailings, comprising mainly pyrrhotite from the mine near Sudbury, Canada, was placed in the vessel for electrolysis. Added a sufficient quantity of liquid cleaners containing hydrochloride acid in the vessel, so that the pH of the resulting suspension was less than two. The ratio of the mass of tailings to the weight of fluid equal to 1:5,6. Tails used in the study contain 0.8% Nickel (dry weight).

[0047] Included electrical energy and applied through the electrodes to activate the suspension. After the time T1 for five hours the current was removed, and the suspension was left under anoxic conditions.

[0048] the Concentration of Nickel in liquid acidic filtrate was checked at the end of the induction period, namely before the beginning of a phase of rapid dissolution, and found it equal to 143 milligrams per liter. The Nickel concentration in the liquid acidic filtrate is again checked in three hours, after gas evolution N₂S, namely at the end of the phase of rapid dissolution, and now it was found that the Nickel concentration is equal to 1160 mg / liter. Energy consumption during electrolysis amounted to five kilowatt-hours per kilogram of recovered Nickel. Restored approximately 77% Nickel.

[0049] As mentioned, the time period T1 starts, when the oxidation energy is applied to the cell. Perry the on time T1 ends, when the amount of energy delivered in such a way that the metastable polysulfides are at maximum, and the change to a stable elemental sulfur, mainly, has not started yet. This change from unstable sulfide to stable sulfur can be detected by monitoring the speed at which Fe is in solution in the acid. When the dissolution rate of Fe starts to decrease, which is an indicator, then begin to form a stable form of sulfur and replace unstable polysulfides.

[0050] Preferably, therefore, the account must maintain at time T1 relative to the several parties processing. It is then possible to determine whether the time constant T1, the party to the party (which should be, if the parameters of the electrolysis of suspended solids in the reactor are constant). Then, the process control can be adjusted so that the energy source is turned off (in the case of electrolysis) just before the appearance of stable monosulfide.

[0051] In the case where the activation is performed using a chemical oxidizing agents, if the heat is added by using, for example, the heater may be turned off the heater, which is controlled by the end of the activation method. But if oxidative energy put into suspension by the initial addition of chemicals to which zvezi, energy can no longer be disabled, and in this case, the amount of energy is regulated by regulating the amount of energy that is added first. In this case it would be advisable to perform preliminary tests to study only what is a suitable amount of an added oxidizing material that will guarantee full (or partially full) activation on the one hand, but no (or nearly no) sverhokislennoy on the other side.

[0052] alternatively, the developer could decide to set the timing simply by method of trial and error. However, the change in the dissolution rate of Fe is quite easy to control, and it is used to determine when the end of T1, i.e. when to switch off the current at the position of the electrolysis.

[0053] Some further aspects of the control phase induction or activation of T1 (before the phase of rapid dissolution T2) will be described now.

[0054] the Developer needs to ensure that a sufficient number of oxidative energy comes in a suspension that mineral is fully activated before disconnecting or cancel energy of oxidation. On the other hand, the developer needs to ensure that the mineral was not verhecken, as this could lead to the formation of a stable form of sulfur that can asseverate mi is oral.

[0055] it Was recognized in the invention that will probably be quite sufficient boundary between these two phenomena, at least in normal situations, is likely to meet on a commercial scale. Thus, if, in a particular case, the amount of energy of oxidation required for full activation of the mineral, was, for example, hundreds of units and if the amount of energy of oxidation, which can lead to soroceanu, equal to two hundred units, this ratio is two to one will be considered as adequate border.

[0056] Adequate boundary is what will allow the amount of energy of oxidation, which is applied to the suspension during the induction phase, be controlled accurately enough for the effective operation of the oxidation method, without the need to resort to subtle (and expensive) detailed controls of the way. It was recognized that the boundary between full oxidation and sverhokislennoy will, in many cases, even more than mentioned the border of two to one.

[0057] Since it is so, the developer can ensure that the length of time the way T1 can be set by simple trial and error. If you want to see way more accurately, you can observe the redox or oxidation-reduction potential of the solution. Read redox potential (SH) about 200 millivolts means, oxidation was essentially completed.

[0058] Measurement of the redox potential can be used to display mainly the beginning of T2 (phase rapid dissolution)as the redox potential, then as will be observed, will go down dramatically. However, the redox potential does not provide such a good definition of the end of the fast-dissolving, in which there is no sudden change in the measured voltage at the point. On the other hand, the control of hydrogen sulfide provides a strong signal the end of the fast-dissolving, as the allocation of H₂S then stops.

[0059] the duration of the periods of time T1 and T2 vary depending on Mineralogy, the strength of the acid, temperature, density, and other factors. It is unlikely that either would take more than about six hours, or no less than about half an hour.

[0060] during activation, the sulfide mainly breaks down as follows: iron goes into solution in the acid, while sulfur is formed or deposited as unstable polysulfide species. This event may be determined by monitoring the speed at which the iron and sulfur are included in the solution: if the iron dissolves faster, which means that happens activation of who I am.

[0061] When the activation ends immediately, the rate of dissolution of iron begins to fall, and the speed becomes more than just smooth. Thus, the completion of activation can be determined by monitoring the speed of dissolution: if the rate of dissolution of iron faster than sulfur, activation is still in progress (i.e. sulfur still settles); if the rate of dissolution of iron is significantly reduced and/or if the speed be more precisely even, further oxidation will now create a more unstable forms of sulfur, i.e. now the activation fails.

[0062] In the state of sverhokislennoy, sulfur beginning to form stable species. One way to determine this, i.e. determine sverhokislennoy, is the observation of the sediment in the presence of sulfate: if dissolved sulfate content begins to rise, it is an indication that unstable varieties begin to disintegrate.

[0063] with regard to control temporal correlation period T2, the developer preferably should ensure that the allocation of N₂S of mist. Gas hydrogen sulfide, of course, very easy to identify. The beginning of discharge H₂S signals the beginning of a phase of rapid dissolution and the beginning of the period T2. The end of discharge H₂S gives the signal that way rapid dissolution and the time T2 has completed the camping.

[0064] Although it is very easy to detect the release of hydrogen sulfide, observation of the phase of rapid dissolution can be done in other ways. For example, the concentration of Nickel in acid can be measured periodically, which would make the detection as to when rapid dissolution begins and ends. In addition, the measurement of the redox potential, i.e. the redox potential using standard hydrogen electrode, can be used to determine the development phase oxidation and weakening phases of rapid dissolution.

[0065] once the phase of rapid dissolution is completed, now it remains to be extracted dissolved Nickel from acid. Acid contains dissolved iron with dissolved Nickel. A typical ratio would be one hundred parts of dissolved iron to one part of dissolved Nickel. Traditional techniques, such as electrochemical separation, can be used for extraction of valuable metals from acid. The acid was separated from the remaining undissolved solids, which can be discarded. Then an acidic liquid (containing dissolved metals) moved into the position of electrochemical separation, preferably through the position of separation, in which a certain amount or more dissolved iron separated re the extraction of Nickel. May require an additional stage of extraction solvent to increase the concentration of Nickel. A large part of the liquid acid should be restored and used again at another party sulfide-acid mist.

[0066] To repeat: it was not meant that pyrrhotite is the only mineral that can be created to expose the phase of rapid dissolution, as described. It may be that other minerals can be created for the same, although could be suspected, in less commercially viable scale than pyrrhotite. Anyway, it was recognized that the pyrrhotite is common, if not universal, feature of sulphide tailings that contain Nickel and, it is likely that resources should make pyrrhotite to undergo a phase of rapid dissolution is much less than the resources that are needed for the same with other sulfide minerals.

[0067] the Method described here leaves a lot of tails already in an activated state. This is the initial state, which can make a lot of tails less dangerous. Permanent tails, if given a chance to oxidize, can create AMD (drainage acid mine water), which is a great problem of pollution. The fact that the tails have already been partially oxidized by reactions described in this description makes the tails are now much less OPA is diverse and less likely to work for AMD, even if the tails are completely discarded. Huge (traditional) the cost of providing permanent necessitate mass of sulphide tailings (which will have to be set in any case, many of the competencies) can be compared with the cost of extraction of Nickel from the mass of tailings procedures described here, the offset value extracted Nickel. Will be observed that the tails were presented (almost) completely safe for anything.

[0068] As mentioned, during the phase of rapid dissolution, a greater amount of sulfur in the sulfide mineral is converted into hydrogen sulfide gas. H₂S can serve as a simple source material for the production of sulfuric acid, and such locally produced acid could be used as the acid in the solution. If you find that sulfuric acid will not be as suitable as, for example, cleaners containing hydrochloride acid, but if the sulfur can be obtained from H₂S (which can be collected and, in any case), it will probably be much more economical.

[0069] the cleaners containing hydrochloride acid is a suitable acid in this application because of the ability of CL^-ions to act as a ligand for many metal species. In addition, CL^-has the ability to affect passive layers that may be formed on the mineral on the bushes electrochemical oxidation.

[0070] This invention relates to the extraction leaching of valuable metals such as Nickel, which are found at low concentrations in sulfide minerals. This invention has been described primarily in its relation to Nickel, which is of Nickel sulfide and iron sulfide minerals, but the invention can be applied to copper, gold, lead, zinc and other metals in their appropriate form of sulfide mineral. Whatever other metals were not present in sulfide minerals, they are also likely to leach. As mentioned, it is known that the mineral is pyrrhotite able to develop economical for the exposure phase of rapid dissolution. It is possible that other minerals as may be, have the same ability, especially because of the economic situation changed.

[0071] it is Also possible that the method of extraction of precious metals from sulfide minerals, as described here, can be economical alternative to fusion for the standard high-quality ores, not least because of the reduced impact on the environment of these methods.

[0072] Various embodiments of the invention have been described herein as having various specific features. It should be clear that the characteristics of a variant of implementation can be added to, or replace the ü in, other options for implementation, if not stated otherwise, or if it is clear in the context, such substitution or addition will be physically or chemically unacceptable.

[0073] the Numbers shown in the figures, can be sorted as:

21 the vessel for loading of raw materials/electrolysis

23 the anode plate on the bottom 21

25 is suspended from the cathode

27 mechanized stirrer

29 power supply DC

30 anoxic vessel

32 capacity for acid

34 separator solids/liquids

36 position extraction

38 accommodation undissolved solids

40 delivery of liquid acid containing dissolved metals

43 acid for dilution

45 electrochemical allocation position

47 repository for the collected metals

1. Extraction of a precious metal from a source material, in which the precious metal is found in small concentrations, including the formation of mist from the mass of the starting material and the volume of acid, the translation of a precious metal in the solution and removed from the solution, characterized in that as starting material used material, the main part of the mass which consists of a sulphide mineral of iron, after the formation of the suspension it is placed in the activation vessel and hold the activation suspension by summing up the energy at a relatively slow / min net and and at time T1, providing the oxidation of minerals and their activation is completely or almost completely during the period of time T1 sulphide mineral of iron dissolved in the liquid acid and when it detects a significant reduction in the rate of dissolution of iron finished the period of time T1 by the cessation of energy in the activation vessel and placed activated, suspended in anoxic vessel under anoxic conditions for a period of time T2 for dissolving a precious metal, within which the sulfide mineral is dissolved at a relatively high speed, which then begins largely to subside.

2. The method according to claim 1, wherein the source material includes tailings and sulphide mineral in the mass includes pyrrhotite.

3. The method according to claim 2, in which the valuable metal is Nickel, and at least some of the valuable metals present in pyrrhotite in solid solution or in the form of small prorastanii of pentlandite in pyrrhotite, or both.

4. The method according to claim 1, which includes ensuring that suspended in the activation vessel is at a pH of about 2 or less, and the suspension is of such consistency and coherence that suspension is mixed.

5. The method according to claim 1, wherein the acid is hydrochloric acid.

6. The method according to claim 1, in which the acid is Erna acid, at which collect gas hydrogen sulfide and used it as source material in the manufacture of sulfuric acid, and add the obtained sulfuric acid to the solution.

7. The method according to claim 1, in which the activation vessel and anoxic vessel represent two separate vessel, and the slurry is transferred from the activation vessel to the anoxic vessel between the end of T1 and primary T2.

8. The method according to claim 1, which includes the stages on which see the redox potential in the activation vessel, check that the activation suspension began, checking that the redox potential rose above approximately 200 mV (SHE (standard hydrogen electrode)).

9. The method according to claim 1, which includes the steps that apply energy to the suspension at such speed and in such a period of time T1, in order to avoid sverhokislennoy where sorokiniana is characterized by the formation or deposition of sustainable forms of sulfur or mineral.

10. The method according to claim 1, which includes the supply of energy for activation by electrolysis, which provide the anode and cathode activation in the vessel and thus create an electrolytic cell activation in the vessel in which the suspension is the electrolyte, and electric current is passed between the electrodes for a time period T1, thus partly about what Issa minerals in suspension.

11. The method according to claim 10, in which the anode of the electrolytic cell is covered with diamond doped with boron.

12. The method according to claim 10, which includes the stages on which see the rate at which dissolved metal in suspension over a period of time T1, due to the discovery that the rate at which the metal is dissolved, decreased significantly, finish the period of time T1 by stopping the supply of power to the electrolytic cell.

13. The method according to claim 1, which includes the supply of energy to activate the suspended solids in the form of chemical oxidants and heating the suspension to a temperature of at least 40°C.

14. The method according to item 13, which includes the supply of energy to activate mist formation of oxidants in situ in the solution by adding acid in suspension.

15. The method according to item 13, which includes stages, which form a suspension of the mass of the starting material and the volume of acid, the source material is placed in the activation vessel with enough water to form a suspension, which is so watery that it can stir, and add the acid in the aqueous suspension so quickly that, at least, the main part of the heat provided the temperature of the suspension at least 40°C.

16. The method according to item 13, which includes the stages at which the energy for activation deliver what about the suspension by continuous addition of an oxidizing chemical, see the rate at which the metal in suspended solids dissolved over a period of time T1, due to the discovery that the rate at which dissolves the metal has dropped significantly, finish the period of time T1 stop adding oxidizing chemical.

17. The method according to claim 1, which includes determining the activation is completed and the end of the period of time T1, at which observe the rate at which the iron goes into solution, to celebrate the end of activation with a significant decrease in the rate of transition of iron in the solution, apply a sufficient amount of energy to ensure the full activation of the mist.

18. The method according to claim 1, which includes the stages on which see the presence of sulfate in acid, mark the point sverhokislennoy point after activation, in which the content of sulfate acid begins to rise, apply a sufficient amount of energy for the full activation of suspended solids, but not enough energy to cause sorokiniana mist.

19. The method according to claim 1, wherein during the time period T2 until the dissolved sulfide, the hydrogen sulfide gas is recovered from the suspension see suspension for separation of hydrogen sulfide gas and celebrate the end of time period T2 in response to the significant decline in the rate of release of hydrogen sulfide gas.

20. The method according to claim 1, wherein the mark is given the beginning of time period T2 in response to a significant increase in the rate of release of hydrogen sulfide gas.

21. The method according to claim 1, in which mark the beginning of time period T2 in response to the significant drop in the redox potential of the sediment.

22. The method according to claim 1, wherein the activation mark formation on or in the mineral is unstable or metastable polysulfide forms, and activation is considered complete when adding additional energy, mainly not able to further increase the formation of unstable or metastable polysulfide forms.

23. The method according to claim 1, wherein the precious metal comprises Nickel or Nickel, and the source material includes low-grade ore or is low-grade ore, tailings, or concentrate enrichment.