RU2065503C1 - Method for recovery of metals (its versions) and dump - Google Patents

Abstract

FIELD: recovery of metals including gold and silver from biologically oxidizer sulfur-containing ores with low content of metals. SUBSTANCE: method for recovery of metals includes formation of macroparticles from ore particles and inoculating agent containing sulfur-oxidizing bacteria. Additionally macroparticles may contain agglomerant resistant to the effect of acids and bacteria. Formed of macroparticles is dump. Ore in dump undergoes biological oxidation and metals are recovered by leaching. EFFECT: higher efficiency. 24 cl, 5 dwg

Description

 The present invention relates to the reduction of metals, including gold and silver, from biooxidized ores containing sulphide and / or elemental sulfur, such as sulphide-containing leachable pyrite, arsenopyrid ores, refractory carbon-sulphide ores, pre-treated and post-processed tails, poor ores previously considered waste, which, however, have a fairly high metal content, as well as covering ores, which have a relatively low metal content and m The ogut is considered waste rock.

 Known methods in which there is provided a mechanical increase in the access of biooxidation bacteria to ore. These methods (1) offer mixing of ore in tanks, sludge, providing circulation in tanks or rearrangement and mixing of material, including loosening, formation of sludge, movement of material, use of vats with mixers and the corresponding formation and use of rock material.

 However, when processing large quantities of gangue material and tailings material, the usual considerations acceptable for high quality ore containing noble metal do not lead to success. When processing waste rock, for economic reasons, a one-time dump formation is performed, that is, to the depth, size and availability of the reagent and so on. In addition, for biooxidation, the time of inducing biooxidants, growth cycles, biocidal activity, bacterial viability and other factors become important, because the availability of the reaction, particle size, precipitation, compaction become irreversible for economic reasons after the formation of the dump and cannot be restored, except for a very small volume. The biooxidation process is characterized by problems associated with compaction of waste dumps, channel formation, lack of nutrition, carbon dioxide or oxygen, and an unequal distribution of biooxidizing bacteria.

 A known method for the extraction of metals from ores, including the formation of dumps, biooxidation of sulfide ores in the dump and the recovery of reduced metals (2).

 The disadvantages of the known method are similar to the previous method.

 The present invention is based on the task of developing a method of biooxidizing an ore containing sulfide and / or elemental sulfur to reduce metals by selecting appropriate conditions for the reduction of metal dispersed in ore or occluded in its matrix, which would increase the yield of noble or base metals from ores when increase its efficiency.

The problem is solved in that a method of biooxidizing an ore containing metal and matrix material is proposed, in which sulfur is in a state of oxidation reduction from zero or less, but no more, and more precisely in the form of sulfide and / or elemental sulfur, as well as clay and / or fine dust particles, providing for the use of an acid-resistant water-soluble vinyl polymer compatible with biooxidizing microbes, obtained by step polymerization as an agglomerating agent, which according to the invention includes:
arbitrary regulation of pH of the ore to a pH of less than 2.5, separately and together with partial agglomeration in an acid solution;
the formation of particulates from ore particles interspersed with microbial agents (agent) capable of at least partially oxidizing sulfur;
the formation of a dump (piles) of these particles;
sulfur biooxidation in the matrix and
recovery of the required amount of metal from either a biooxidizing solution or a special leach for a certain metal.

 The term "ore" or "ore material" as used here includes not only ore as such, but also concentrates, tails and waste rock, where, however, there is a sufficient metal content to justify the reduction treatment.

Recoverable metals relate to:
group IB of the Periodic system of elements (copper, silver, and gold);
group IIB (zinc);
group IVA (germanium and lead, in particular lead);
VA group (arsenic and antimony);
VIA group (chromium, molybdenum, tungsten, in particular tungsten);
group VIII (iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, especially nickel, palladium and platinum, and metals from the actinoid group (uranium).

 Of all these metals, copper, silver, gold, zinc, cobalt, nickel and uranium are preferred. Gold is the most necessary metal of these.

 The matrix material, in addition to the required sulfur content, may contain one or more inorganic metallosulfur compounds containing the required amount of sulfur and metal from the above.

The metal may be present in the ore material in the form of:
1) a metal, for example gold, dispersed and enclosed in a matrix;
2) compounds, for example in the form of a metal oxide dispersed or enclosed in a matrix;
3) as a component of a matrix material, for example, metal sulfide.

 The method according to the invention facilitates access to metals in the recovery process in the sense that the biooxidation of sulfur makes it possible to carry out further reduction processing of the elements of the metal or compound, and also makes this metal soluble and, therefore, available for the recovery process.

 The method according to the invention is preferred for the recovery of gold from ores having a sulfide sulfur content and a low gold content, and in particular where the matrix material contains an iron-sulfur compound. Of particular interest are refractory pyrite and arsenopyrite gold ores with a low gold content.

 The invention is particularly applicable to ore materials with a high content of clay and fine particles. Clay particles can migrate in the dump and, swelling and falling into the channels between the ore particles, clog these channels. Small particles (50 wt. 200 meshes) can also migrate and, having accumulated, close the passages for seepage in the dump. This creates areas of low permeability for working fluids. Such ores are difficult to access for leaching in dumps, as well as for other types of processing, since clay and particles condense and clog fluid channels in the dump, interfering with the circulation of the working fluid in them. This worsens the uniform treatment of the particles that make up the blade, since the working circulating fluid reaches these particles unevenly, leaving some part without power and, therefore, untreated. Therefore, the extraction efficiency decreases, the washing time and the leachate consumption increase.

 The effectiveness of the agglomeration helps to prevent the migration of clays and / or particles from the particles to the dump, resulting in increased resistance to the flow of the solution.

 A measure of the effectiveness of agglomeration can serve as the rate of leakage of the solution.

 When testing the permeation rate, the cylindrical column is loaded with the test sample and the permeation rate is measured.

 Each sample is prepared in such a way as to maintain constant conditions from sample to sample, for example, moisture content, particle sizes, particulates, the ratio of clays and / or dust particles and solid particles, surface area, etc. the only difference being the presence or absence and quantity of the agglomerating agent being tested. This allows you to accurately compare the different methods of agglomeration. The column is loaded with a certain volume of the prepared sample to a given height. The filter solution is introduced to a certain level and circulates in the column for a certain time, while maintaining the height of the column at a given level. After a certain time, the rate of leakage is measured. A decrease in speed indicates that clay and dust have separated from their particulate matter and clogged the ducts.

 Another measure of the effectiveness of agglomeration to prevent the movement of clays and dust particles is to directly measure the amount of clays and fine particles at different levels in an artificial heap. The equipment and process are the same as when testing the filtration rate, except that instead of measuring the leakage rate at the end of a certain period of time, samples are taken at certain depths in the column, and each sample is analyzed for clay and / or fine particles. Their percentage at each depth relative to the total number indicates a deviation from the uniform distribution, that is, whether they are contained in their particles or separated from them.

 As for real dumps in the field, the effectiveness of agglomeration to prevent this migration is usually determined by observing the formation of dump sites where the accumulated wash solution can be visually determined.

 The term "particles" refers to individual ore particles immediately after mining and formed after primary or secondary crushing and grinding; the term "particulate" means a body or form consisting of individual particles, properly coated with an agglomerating agent, as described above, before, together with or after wetting the particles with an inoculant solution containing bacteria, or an agglomerating agent, as described above, used for the same system, as well as an inoculating solution, but forming particles from a solution containing sulfuric acid, an inoculating solution containing individual bacteria of a special strain or a mixture of bacteria. Such construction or the formation of particulates, as well as the construction of the dump create favorable conditions for the reactant, that is, the distribution of biomass, dispersion and access to: a) the quantities of metal in the ore, which is, for example, in small quantities; b) to sulfide and metal contained in small concentrations in ore. None of the links refers to an economical method that improves the initial formation of the blade for the convenience of the biooxidative process, and the development of an effective cyanidation method to restore the noble metal after biooxidation in the initially correctly formed dump.

 A major aspect of the invention is a particulate ore biooxidation step, including pre-treatment and post-treatment steps regarding biooxidation. The subsequent stage of metal reduction to extract noble and / or base metals from a biooxidized ore body becomes more expedient, since ore particles are formed from the very beginning, especially ore particles having a high clay content and an acid and bacterium-resistant agglomeration agent of the described type are used with bacterial membrane, which, as a result of improved oxidation, makes the ores extremely susceptible to further reduction, for example, cyanide or other kstragiruyuschim agent to extract the desired amount of metal (s) from such ore biooxidation. Further, the corresponding agglomeration agents according to the invention facilitate biooxidation and, mainly, further extraction processes.

 The invention provides a combination of steps that make it possible to process ores, especially ore materials with a low content of noble metal, which until now have been considered waste rock, not suitable for recovery from them noble metals due to indicators that limit the possibility of processing, which relates ores with a high clay content, in which permeability is difficult, and with the biooxidation of gold ores having a low, medium and high clay content and low sulfur content. A low sulfur content occurs in ores having approximately less than 0.2-0.3 wt. sulfide.

 However, although the invention describes low sulfur cases in the reduction of precious metals such as gold, it also has value for high sulfur ores. Low clay ores are those in which the clay content is approximately less than 5 wt. the average clay content in the ore is approximately less than 20 wt. high clay content in ores about 30 wt. and more.

 Thus, in accordance with the method according to the present invention, waste waste with a gold content of 2.0 grams per ton of ore, even up to 0.6 grams per ton of ore, can be economically processed to recover it.

 Gold is preferred above 0.6 grams per tonne of ore.

 Naturally, this invention is applicable to ores with a higher gold content, but for ores with a high gold content there are a number of other methods and means for its successful recovery, so this invention may be one of them.

 Thus, it is considered appropriate in accordance with this invention to process tailings, gangue, overburden and waste materials already used if the amount of precious metal in such ore bodies is in the range of about or above 0.6 grams or its monetary equivalent in the presence of gold with silver or single silver; if the ore is processed on the acid side of pH, with a pH value of 1.5 or more; if the ore contains clay materials in an amount of approximately more than 10 wt. and if the ore was agglomerated with appropriate acid resistant agglomerating agents.

 Further, it was found that the improvements described here make the method extremely suitable for low-grade ores when processed in a pile or dump and provide significant results, despite the presence of clay in the ore when processed by this method.

 For example, this invention assumes proper agglomeration by the distribution of fine-grained and coarse-grained ore material with a significant clay content, with an accompanying correct distribution of biooxidizing bacteria.

 It is clear that in the ore body contained in the dump, the particles have different sizes and different locations, which is also the subject of the invention from the point of view of providing access to areas that were previously considered "dead" in the dump, and now they are accessed as a result of this inventions.

 These ore macroparticles, correctly formed and distributed in the dump, provide advantages, since the agglomerated inoculated biooxidative material comes into contact with individual particles and / or smaller particles and is suitably placed on large particles to form the desired structures. It should be noted that agglomeration with only an agglomerating agent is the only acceptable way to form particulate matter. Inside such formed particles or on their surfaces, a corresponding stable flora is formed, which contributes to the correct distribution of bioreactant bacteria throughout the ore body in the dump formed from various, even undesirable, very small particles, such as clay and small particles of "sludge" of various compositions and impurities with larger particles. The same or different bacteria can now be introduced into the right place, determined by temperature, pH, biocidal, access, saturation with water and other factors. Further, this invention also relates to the proper formation of particulate matter by agglomeration from crushed ore rocks during the formation of a dump with simultaneous treatment with a working fluid containing bacteria necessary for certain layers of the dump.

 Other various features of the formation of inoculated particulate matter in accordance with this invention will be described in connection with the formation of a blade and the distribution of biooxidant bacteria by weight of ore and dump.

 In addition to the foregoing, pretreatment steps may include treating sulfuric acid to neutralize or partially neutralize ores with high acid absorption (thus also partially agglomerating ores), followed by treatment with an agglomerating agent and further inoculation and formation of particulate matter, and the distribution of the bio-oxidizing bacteria by weight ore as it is processed for deposition on the dump.

 In accordance with the invention, the formation of particles, coating their surface and the distribution of biooxidant in them are very successful.

 These advantages provide extremely favorable access of bacteria to the sulfide matrix of the ore in particles of various sizes, as well as the rapid growth and reproduction of bacteria.

 According to this invention, the method provides for the processing of arsenopyrites and the like ores and develops subsequent or additional treatment with biooxidative leaching solutions, thus making it possible to choose the optimal treatment option for each individual type of ore.

 Due to the possibility of obtaining mixed particles of ore and bacteria of biooxidants in the dump, the possibility of layer-by-layer formation of the dump, as well as the possibility of adding various types of bacteria at different points of the formation of particles, the method helps to design the plastic construction of dumps. This plasticity is manifested in a layered arrangement, alternating or combined with mutually compatible bacteria, which is appropriate for processing the material, since it opens up access to other components in the ore, for example, acid-insoluble carbon.

 Thus, various bacteria that have excellent properties for processing ore materials containing biocide-active metals, such as arsenic, antimony, cadmium and the like, in large quantities, in the presence of iron, ensure the successful introduction of various cultures in various places of dump and at various stages of processing.

 As a result of this, the induction period of growth is reduced, the access of air and carbon dioxide is improved, as well as the introduction of food and other additives, more biomass is retained throughout the entire dump, leakage is improved, tampering and channel formation are minimized, there is no water logging and so on. The new practice of particulate formation and dump construction provides outstanding results in the extraction of metals from ore, in particular noble metals from metal ores with a low content. One of the advantages of the invention is that in the first stage of processing, carried out under acidic conditions using special means of agglomeration, conditions are created for the further reduction of the desired metal, for example, in the second stage, i.e., cyanidation or treatment with another leach to extract the metal, or reduction directly from a bioleach solution. These advantages, which the second stage gives, result from improved porosity, achieved by the fact that the agglomeration agent is not affected by bioleaching, as well as by the good permeability of the leach, which, in turn, eliminates the separation of clay from its particles and so on. In addition, the extraction speed is increased as such; Significant gains have been made in providing access for cyanide or another leach or leach solution; reduced consumption of cyanide (leach); conditions are created for the regeneration of the leach agent and various variations during processing, and it also provides the opportunity to simplify the process of neutralizing the blade, if necessary, the need for neutralization is reduced due to good washing as a result of the first stage of processing the blade with biooxidizing material, and so on.

 Therefore, the formation of a dump for treatment with cyanide or another leach is no longer necessary due to the preparation of a dispersed porous biooxidized matrix, which makes it possible to wash and neutralize the acid material of the dump for subsequent cyanidation or other types of ore leaching. These and other advantages ensure the free use of cyanocidal fungi and other microorganisms that reduce the amount of cyanide, for subsequent processing of the exhausted blade. At the same time, improved access of cyanide to and between particles allows to do without it.

 FIG. 1 schematically depicts a conveyor belt of a device for agglomeration of particles having the necessary properties for the formation of particulate matter in a dump, for subsequent biooxidation and leaching of metal.

 FIG. 2 depicts a cross-sectional area of a prepared ore particle.

 FIG. 3 schematically depicts an embodiment of the present invention in a dump of bio-oxidizable ore material, which is then reconstructed and treated with cyanide.

 FIG. 4 depicts another embodiment of the invention in a dump of ore material biooxidized by the racetrack method.

 FIG. 5 schematically depicts yet another embodiment of the biooxidative leaching of an ore dump using a leach or other solution.

 The conveyor system shown in FIG. 1, consists of a loading hopper 1, which contains sulfide ore 2. Ore 2 is fed to a conveyor belt 3, inclined to the vertical and having a spray device 4, operatively connected with the conveyor 3. The conveyor 3 is lapped with the inclined to the vertical conveyor belt 5, which, in turn, is overlapped with a steeply inclined belt conveyor 6, from which ore particles 7, gradually forming on the conveyor 3, are discharged, forming a dump 8.

 In FIG. 2 shows the cross-sectional area of the particulate 9. As shown, the individual particles 10 are covered with a bacterial shell 11. Since each ore has different fracture characteristics and the particles can be crushed, crushed, and even in kind from a mine, it is clear that particles 10 can be present in ore in various forms. Clay particles are usually smaller and are located on the surface of large particles. It should be noted that these particles are quite durable and can withstand substantially any compaction and / or when exposed to pressure from the dump material. Moreover, large clay particles withstand the action of washing solutions. Typically, for sulfide ores, the particles should be about 2.54 cm or less in size, with about 45-50% of the sulfides in the particle being oxidized. The optimum size for sulfide ores is about 1.27 cm to about 0.63 cm, which makes it possible to 80% oxidize sulfides, however, depending on the period of time allotted for this. Clay particles are smaller in size and therefore must be agglomerated and bonded to particulate matter or formed into particulate matter.

 For carbon sulfide ores, the particle size should be about 3.81 cm or less, while approximately the same amount of sulfides is oxidized as in sulfide ores. The optimum low size limit is approximately the same as in sulfide ores.

 For cyanidation, the size of the particles should be about 2.54 cm or less.

 In FIG. 3 depicts a blade 12 in accordance with this invention. The blade 12 has an “induction” section 13 just formed and schematically shows the time delay before the much more important biooxidation reaction. Section 14 of the blade 12 schematically depicts a dump in the most active stage of biooxidation. Section 15 depicts the state of final biooxidation and the period when a predetermined content of biooxidized sulfide in the ore is achieved. Upon reaching this content, section 15 is drained. When the blade 12 is in its most active stage, it may be necessary to cool it with a cooled solution of the biooxidant that has been recycled, or with a cooled supporting, i.e. nutrient, solution.

 After the desired percentage of oxidized sulfide in section 15 of the blade 12 has been reached and the blade 12 has been drained, the blade 12 is washed for a long time, as schematically shown by section 16 of the blade 12. After a period of time necessary for washing, for example, for two weeks, or depending on the residual acidity of the iron in the washing solution, section 16 is reconstructed, for which it is destroyed, and using the conveyor 3, the ore is sintered with cement or lime to create a new dump 17, which is cyanide or processed is added with a solution of thiosulfate.

 FIG. 4 schematically depicts an embodiment of the invention where a more limited space is shown, that is, a “circular” blade 18, which is constantly being formed and re-formed. Thus, the strike zone 19, which is a free surface, moves gradually in a circle formed by a "circular" dump 18. As new layers of ore 7 are added to the face 20, the agglomerated ore gradually approaches a new face 21 of the freshly inoculated ore 7.

 From the corresponding moving rock removal front 22, ore is discharged to an alkaline dump 17 (FIG. 3). Likewise, the moving wash front 23 and its corresponding new wash front 24 show a wash section 25, which reduces the acidity of the bio-oxidized ore in the "circular" dump 18.

 As shown in FIG. 5, several individual trunks can be bio-oxidized. After the biooxidation reaction started in the dump 8 and then ended, the dump becomes a dump 26, which can be drained. The blade 26 is washed and receives the designation 27.

 The water 28 of the dump 27 is mixed with the drainage solution 29 from the dump 26 and also partially with the flow from the dump 8. Although the new dump 30 of the particulate was pre-agglomerated and inoculated, if necessary, additional solutions can be added to this dump 30, in which the biooxidation of ore sulfides is carried out. 31 bacteria from the tank 32. The biooxidation of the blade 8 is also carried out from the tank 32.

 In the described embodiments of the invention, the dump in the biooxidation phase can be treated with a recirculating biooxidant from 3 to 8 days, and from 3 to 8 days, the nutrient cycle, i.e. the moisture preservation cycle, lasts approximately.

 From 4 to 7 days of recirculation of the biooxidant and the nutrition cycle are sufficient to maintain the necessary active level of blade processing.

 FIG. 5 depicts sequential use of a solution for complete biooxidation, drainage, and flushing. From FIG. Figure 5 shows that all volumes of the solution are reused, including acid, iron ions and bacteria. This is another advantage of the present invention. The solution operation shown in FIG. 5 is also applicable to the embodiments of the invention shown in FIG. 3 and 4.

 As for the term "agglomeration", this is a working term, and in more detail implies the formation of particulates, particle sizes, distribution of particles in the ore body.

 These particles are obtained by appropriate layer-by-layer arrangement, formation and bonding of ore particles. This gives them the necessary properties, which depends on the quality of the acid-resistant agglomerating agent and bacterial inoculation. The consequence of this is an improvement in porosity, permeability, permeability and a decrease in fluid flow.

 For the proper formation of particulate matter, it is important to minimize the effect of clays on the "viability" of the particulate during the biooxidation process and further, in the leaching process, and therefore, agglomeration and inoculation, as well as on the "sticking" of particles and the resistance to crushing of particulate material prepared according to this invention.

 The average dissolution rate of iron according to this invention is another distinguishing feature for establishing the correct formation of particulate ore material by an agglomerating agent and biooxidizing bacteria. The threshold for the rate of dissolution of iron determines the boundary when the particulate becomes substandard as a result of improper agglomeration, on which the porosity and proper construction of the particulate depend.

 Another way that determines the correct formation of a particulate is the length of time before the marking element appears in the leach solution. Such marking elements and conditions according to this invention were determined depending on the ratio in the system of gold, iron and sulfur matrices, as completely soluble iron, soluble ferrous iron, soluble ferric iron, the ratio of ferric and ferrous iron, which should exceed 4: 1 and preferably 3 : 1, soluble arsenic, pH and Eh. Further, the leach rate and the flow rate of the leach solution for solutions with sufficient nutrition and for solutions with insufficient nutrition are also taken into account. In the above description, iron served as a process marker, but another metal that is soluble in biooxidation is also suitable as a marking element.

 With regard to the preparation of ore before the formation of particulate matter, the ore may be untreated, that is, natural raw material immediately after mining, or has already undergone primary or secondary crushing.

 Ore particles are so distributed by size, as was established for the proper formation of particulate matter. Ore materials, which have been crushed in a natural way and are ready for the correct formation of particulate matter, provide the most rapid biooxidation process; at the same time, the most economical crushing method for each individual ore type is taken into account. So, for example, for easily crushed ores, the size should be less, for example, 1.27 cm to minus 10 meshes, and for hard ores, from 2.54 cm to 0.63 cm. Usually, such particles are ensured by the presence of a void. These voids can be formed by a combination of particle sizes and their distribution, particle shape and shape of the resulting particles. Typically, the most favorable results are obtained from almost round particles, but for the entire dump it is difficult to obtain the desired configuration due to the variety of characteristics of various ores. In accordance with the correct formation of particles in the biooxidative solution, there are layered rounded particles, after which the smaller particles (each of which, in turn, is coated) increase to the desired size. Therefore, the formation of particles using biooxidation is a means to increase surface area, but, more importantly, to obtain crushing resistant, despite individual bacterial treatment, particles with increased surface area, which are not affected by the high clay content.

 This physico-chemical effect makes it possible to use bioleaching in practice for processing rock materials that were previously considered empty, that is, with a low content of metal, gold, in particular, and a low sulfide content.

 In addition to the above, inoculation of the biooxidant rapidly initiates a biooxidation reaction. This promotes rapid direct, indirect and galvanic leaching.

 Thus, the iron sulfate obtained by the biooxidation reaction accelerates the reaction as a whole, and it becomes obvious that occluded gold in the pyrite matrix is more suitable for the second stage of the process, i.e. for cyanidation.

 In the event that the desired metal is a component of the matrix material and biooxidation dissolves the metal, the biooxidant solution functions as a bioleach and the desired metal can be reduced directly from its stream. With a decrease in the concentration of dissolved metal in the stream during its recirculation through the dump, the dissolution of the desired metal from the ore is facilitated due to its low concentration in the ore.

 Since ore crushing and grinding constitute a significant part of the costs in the formation of the dump, the method described here is practical for the largest ore particles in size, which makes biooxidation economical.

 The penetrating ability of the bacterial solution and further, the leaching solution, and the formation of particles into particles (this applies to biooxidation) allow the use of large particles, however, the size of small particles plays a significant role. So, for example, clay particles are retained on the surface of the particles, since the agglomerating agent improves the formation of particles, especially in combination with an inoculant solution.

 The formation of particles by means of agglomeration can be carried out with ores having an initial moisture content of from about 2 to 3% where the addition of liquid leads to a moisture content in the ore of a maximum of 8-12%. Higher amounts make solutions incapable. The consumption of a large amount of liquid may be impractical if the ore is not mixed so that the ratio of dry and finely divided ore in the particles is observed. In addition, ore "sludge", that is, small particles, can now be useful in the process of formation of particulate matter.

 However, the best way to form particulate matter is to enlarge or combine the particles using an inoculating solution (as shown in Fig. 1), as well as using agglomerating agents, for example polymer mixtures.

 For ores with high clay content, it is necessary to establish the required amount of agglomerating agent and use a binding agent, that is, acid-resistant polymers or copolymers to improve the “sticking” in the bacterial solution.

 Clay-containing ores are most difficult to leach, since they absorb huge amounts of water, clog channels for the passage of the solution in the dump and, separating from the particles, form an impermeable layer in the dump. Ore material containing the smallest particles is also difficult to leach, as the smallest particles migrate freely with the fluid stream and also contribute to blockage of the ducts.

 The clay content in the ore is more than 10 wt. or the smallest particles more than 30 wt. (200 mesh), or a combined clay content of more than 5 wt. and small particles of more than 25 wt. (200 mesh) involves the inclusion of an agglomerating agent in the formation of particulates, which would serve as a binding agent. Typically, the amounts added are from 22.68 g to 4.536 kg per tonne of ore material. The term "fine particles" refers to a material passing through a sieve having 200 mesh, that is, particles having minus 200 mesh.

 Acid resistant microbial biooxidant compatible water-soluble vinyl polymers obtained by step polymerization include agglomerating agents according to the method of this invention. Such polymers must be acid resistant, since microbial biooxidants, such as T. ferroxidans, require an acidic environment for the survival and oxidation of iron and sulfur, i.e. physiological activity. Further, the metabolism of these microorganisms produces acid and seeks to reduce pH in their environment. Acid is also necessary when leaching material from a dump. So, for the efficiency of the process, preference is given to acid obtained from microbes. Polymer agglomerating agents should be microbial compatible in the sense that they should not be microbial biocidal or impair the viability and metabolism of microorganisms, or cause serious metabolic disturbances. The polymer agglomerating agent should not only be compatible with the microbial biooxidant, but the biooxidation process should not have any effect on its properties. Preferably, the agglomerating agent should not act as a metabolic substrate for the biooxidant, and, more importantly, should not function as a physical support or device for the biooxidant or its colonies.

 The agglomerating agents must be water soluble so that they can be used freely either in solution or in a dry powder by spraying, which would then be soaked during the formation of particulate matter.

 Preferably, the vinyl polymer obtained by step polymerization is acid resistant and alkaline resistant. Resistance to alkali allows the use of leaches with a strong alkaline environment, such as caustic cyanide or cyosulfate to restore metal without reactivating ore material with a separate alkali-resistant agglomerating agent and rebuilding the dump.

Vinyl polymers obtained by step polymerization are those that polymerize after the addition of vinyl or acrylic monomers in a free radical solution. Such polymers have ionic functional groups. Suitable vinyl polymers are selected from the group of homopolymers, copolymers, terpolymers or higher polymers of a compound having the general formula:
CC • R (I)
where: R is nitrile, amide, a carboxyl radical of the general formula COOR ¹ , where R ^{1 is a} lower alkyl radical, preferably having from 1 to 4 carbon atoms, and its water-soluble salts.

 Suitable monomers include acrylic acid, methacrylic acid, ethacrylic acid, α-chloroacrylic acid, cinnamic acid, β-styryl acrylic acid, itaconic acid, citric acid, maleic acid, fumaric acid, maleic anhydride, dimethylamino ethyl acrylate, methyl ethyl acrylate, methyl ethyl acrylate, methyl acrylate, methyl acrylate, methyl acrylate, ethyl methacrylate, acrylamidomethyl propanesulfonic acid, ethyl methacrylate, butyl acrylate, isobutyl acrylate, dodecyl acrylate, 2-ethyloxy acrylate, vinyl acetate, vinyl propionate, vinyl butyrate, α-methyl styrene l, vinyl toluene, propyl vinyl ether, butyl vinyl ether, isobutyl vinyl ether, methyl vinyl ether, ethyl vinyl ether, vinyl chloride, vinylidene chloride, and so forth.

Preferably, the monomer is acrylamide or acrylic acid, or both. It should be understood that the nitrile, amide and R ¹ radicals in formula I can be substituted and that the homopolymer and copolymer can be modified without deviating from the essence of the invention.

 Preferred polymers are unsubstituted and substituted acrylamide homopolymers, acrylic acid homopolymers, acrylamide copolymers with one or more nonacrylic acid monomers, acrylic acid copolymers with one or more nonacrylic acid monomers, cationic and nonionic acrylamide or acrylic acid monomers or derivatives thereof, such as monomers and polymers acrylamide or acrylic acid, and one or more other monomers.

 These preferred monomers, acrylamide or acrylic acid, or both, can be copolymerized with other monomers, such as N-vinyl pyridine, vinyl acetate, styrene, vinyl ester, vinyl halides, vinyl esters or unsaturated hydrocarbons such as isobutylene.

 By "cationic" polymers are meant polymers synthesized from cationically charged monomers exhibiting a positive charge.

 By "non-ionic" polymers are meant polymers from monomers in which the charges are small enough, as a result of which the resulting polymers do not exhibit ionic effects.

 Suitable cationic monomers are those that contain amino or imino groups that produce water-soluble polymers compatible with selected microbial biooxidants. Such monomers can be selected from N-vinylpyridine and its substituted derivatives; alkylamine and its N-alkyl substituted derivatives; aminoalkyl acrylates and dialkylaminoacrylates such as aminoethyl acrylate hydrochloride or aminoethyl methacrylate hydrochloride; and its N-substituted- (N'-dialkylaminoalkyl) acrylamides and salts. The above monomers may be substituted, for example, with lower alkyl groups having from 1 to 4 carbon atoms.

 In addition, other cationic polymers can be prepared by copolymerizing a nitrogen-containing monomer with one or more monoethylenically unsaturated monomers, polymerizing vinyl to obtain a water-soluble, microbial biooxidant compatible polymer.

 Suitable monoethylenically unsaturated monomers may be selected from acrylamide, methacrylamide, acrylonitrile, lower alkyl esters of acrylic and methacrylic acids, vinyl methyl ester, N-vinyl oxazolidinone and N-vinyl pyrrolidinone.

 For example, the cationic copolymers of acrylamide and acrylic acid and their derivatives as monomers can be copolymers of acrylamide and dimethylaminoethyl methacrylate.

 In addition, non-ionic polymers such as polyvinyl alcohol can also be taken into account.

 Nonionic polymers can also be prepared by providing a balanced amount of cationic and anionic groups in the polymer so that while the polymer molecule is nonionic, cationic and anionic functional groups can exhibit cationic and anionic activity, such as in the case of a substrate.

 Therefore, these cationic components may be present in the same polymer molecule with anionic components, such as derivatives of acrylic acid and methacrylic acid.

 The polymer agglomerating agent should have an average molecular weight of from about 10,000 to about 25 million, preferably from medium to high molecular weight, such as a weight equal to the average molecular weight, from several hundred thousand to several million, preferably more than one million. Preferably, the agglomerating agent should include a surfactant or demulsifying agent, for example ethoxylated alkyl phenol, ethoxylated amine or ethoxylated fatty alcohol. Preferred surfactants are ethoxylated alkyl phenols having at least one alkyl group or from 6 to 12 carbon atoms, on average up to 30 ethoxylated groups per molecule. Ethoxylated octylphenol and ethoxylated nonylphenol are preferred ethoxylated alkyl phenols.

 It is desirable that the anionic polymer be a polyacrylamide, moderately anionic, with a high molecular weight, a one-component liquid flocculant, which can be used in an amount of 22.68 g to 2.268 kg of polyacrylamide per ton of ore material, preferably from 45.36 g to 1.134 kg per ton . This material provides excellent agglomerating effect over a wide range of pH in the dump, without destroying the particles and without causing the migration of clays and small particles. The material is particularly suitable for acidic and oxidative conditions during biooxidation. It also has no harmful effect on the microbial biooxidant. In addition, the surfactant used with this acrylamide, oxidized nonylphenol, is also compatible with the biooxidant. At a concentration of one weight percent, in deionized water, it has a pH of 7.

 A preferred non-ionic polymer is a polyacrylamide, non-ionic, high molecular weight, one-component liquid flocculant, usable as an agglomerating agent as an agglomerating agent in an amount of typically from about 22.68 g to 2.268 g of polyacrylamide material, preferably from 45.36 g to 1.134 kg per tonne, which makes agglomeration successful under conditions of a wide range of pH. This material and its surfactant, ethoxylated nonylphenol, provide biocompatibility with microbial biooxidants.

 Each of these materials is readily soluble in water, making it suitable for the formation of particles using a binding agent. Due to their excellent expectation, cleansing, strengthening and dehydrogenating properties in the processing of sludge, they are easily used in the agglomeration of ore particles and clays and / or small particles into particulate matter. As one-component polymer flocculants, they do not require an activator, which makes their use easier and cheaper.

 The preferred agglomerating agent contains from 1 to 5 wt. ethoxylated nonylphenol or ethoxylated octylphenol and 20-40 wt. hydrotreated light distillate, the rest is sodium chloride and water.

 Another agglomerating agent contains 1-5 wt. ethoxylated octylphenol, 20-40 wt. hydrotreated light distillate, the rest is water.

 The sintering agent should be used in an amount of 22.68 g to 4.536 kg of polymer per ton of ore material, preferably from 45.36 g to 226.8 g, optimally from 45.36 g to 1.134 kg per ton, and be in the form of a dry powder sprays of mortar, spray or foam.

 Such a system makes it possible to evaluate an agglomerating agent for using its properties in the process according to this invention. Similarly, the acid resistance of an agglomerating agent according to this invention can be measured on a scale of 1 to 5 compared with the acid resistance of a standard agent, wherein the polyacrylamide, for which an amount of 2.5 is given, retains sufficient particulate integrity for a period of at least 200 days in an acidic environment with pH from 1.3 to 2, and preferably 1.8, for caustic cyanidation (at a value of 1, the standard agent has the worst effect).

 Thus, it is possible to evaluate the effect of the agglomerating agent for use in the present invention with respect to acid resistance. Since the properties of the particles change over a long period and due to a characteristic long period of biooxidation, an assessment based on the above standards of agglomerating ability and acid resistance is appropriate for putting the invention into practice.

 Together with acid resistance, bio-oxidation resistance is also measured in the same way using the same standard as described above, on the same scale. There should be a balance of three properties that promote agglomeration, acid resistance and biooxidation resistance in a sequential mode, where the average values should be in the range of from about 2 to 5, preferably from 2.5 to 5, so that with a higher allowable agglomeration ability a lower value is allowed for the remaining properties. The average value of the three properties should be within 2.0 and above, preferably 2.5.

 In the invention, the aforementioned agglomerating agents are used in the formation of particulates from particles containing ore material and clays and / or small particles in combination with an inoculating agent containing bacteria capable of at least partially biooxidizing the sulfur content using, if necessary, acid treatment. The particles are preferably treated with an agglomerating and inoculating agent simultaneously with the formation of particulates or in stages, when the particles are first treated with an agglomerating agent and then formed into particles in the presence of an inoculating agent. Typically, the particles can be treated with an agglomerating agent before the formation of particulates or simultaneously with the formation. Ore particles can also be treated with an inoculant agent before, during and after the formation of particulate matter. Particles can be pretreated with acid before particulate formation or after, and particulate can be formed in the presence of acid.

 A typical method for the formation of particulates is to spray liquid onto the ore; immersion in the liquid bath of the conveyor belt with ore and other methods, such as the use of worm (screw) extruders, can also be used. However, it is important that the moisture content and the formation of particulates are such that particle distribution and sufficient surface area are ensured during inoculation, which contributes to the rapid progress of the reaction, i.e., the induction and oxidation of sulfide reagents within an economically acceptable time frame.

 For example, the present invention provides for the correct formation of particulate matter by distributing fine and coarse particles of ore material with the concomitant correct and denser mass distribution of the bio-oxidizing bacteria, as shown in FIG. 2.

In accordance with the invention, the following bacteria were useful for the process:
Group A. Thiobacillus ferroxidans; Thiobacillus thioxidans; Thiobacillus organoparus; Thiobacillus acidophilus;
Group B. Leptospirillum ferroxidans;
Group C. Sulfobacillus thermosulfidooxidans;
Group D. Sulfolobus acidocaldarius, Sulfolobus BC;
Sulfolobus solfataricus and Acidianus brierleyi
The above bacteria are further classified as either mesophiles (groups A and B), i.e. the microorganism is capable of growth at medium temperatures (i.e. about 30 ^° C), and optional thermophiles (group C) (i.e. at a temperature of 50 ^° C to 55 ^o C), or obligatory thermophiles (group D), which are microorganisms that can grow only at high (thermophilic) temperatures (i.e. approximately above 50 ^o C).

 It is also desirable to apply the present invention to ore materials in which the amount of the desired metal and / or matrix material is contained in an inorganic metal-sulfur compound in which the metal part of the molecule is different from iron and for which bacteria that also oxidize the selected metal can be used.

 In order for the particles described above to be properly biooxidized, the ores must have a certain mineralogical characteristic. These ores should not contain more than 1-10 wt. calcite, dolomite or other carbonate minerals and must have at least 0.2 wt. sulfide. Calcium carbonate increases the acid absorption of the ores and makes them very refractory to process. These types of ores must also have a high sulfide content to produce the acid necessary for carbonate neutralization, and if necessary, sulfuric acid can be added to regulate pH within the range required for biooxidation.

 Perhaps the production of bacterial biomass.

In accordance with the above, a solution containing one or more of these bacteria with a biomass concentration of 10 ⁵ to 10 ⁹ bacteria per milliliter of solution is used to form ore particles from the particles in such a way as to coat the particles with the necessary layer of bacteria, and then, when properly the formation of particles by small particles adjacent to the core of the material. The growth of small particles and the formation of such particles from them, which have a surface to volume ratio of at least 100 square centimeters per 100 cubic centimeters of ore, provide a threshold value.

 Although long leaching periods, i.e., low rates, are permissible, and the present invention allows for low leaching rates, the preferred method requires induction periods of at least 5 to 20 days for the same amount of marking sample during ore processing for the proper formation of particulate formation.

It should be noted that for bacteria of group A and B the temperature should not exceed 35 ^o C, for bacteria of group C the temperature should not exceed 55 ^o C, for group D not exceed 80 ^o C. Therefore, based on the temperature profile in the dump of empty ore rock when sulphide oxidation is in full swing and the highest exotherm of sulphide oxidation is achieved, the dump can be washed with a cooled leach or other means of cooling (and / or heating) must be provided when constructing the dump. Further, the dump can be constructed using appropriate bacteria, taking into account the temperature limits for this type of ore, for example, for ore with a high sulfide content. As is known, due to sulfide oxidation rates and concentrations, the temperatures in the leached dump are not uniform, and often the bacteria are not able to maintain viability if the temperature is not properly controlled, as well as when using inappropriate bacteria. Therefore, the correct construction of the waste ore dump, where particles are formed using the appropriate solution of thermophilic bacteria, prevents the action of these temperatures in the ore body, which is an advantage of the present invention.

 Further inoculation of the ore with the addition of a variety of bacteria can accelerate the rate of the biooxidative reaction and is part of the process described here. The use of the inoculant after the construction of the dump makes the process suitable for processing ores containing many metals that have biocidal properties. For example, arsenic resistant strains can be introduced from the very beginning. Arsenopyrites should gradually dissolve during biooxidation. However, leaching of arsenopyrites leads to the formation of free or elemental sulfur. Therefore, Thiobacillus thiooxidans can be used to prevent the inhibitory effect of free or elemental sulfur. In addition, the presence of free or elemental sulfur causes a high absorption (consumption) of cyanide.

 As described above, the oxidation of sulfide occurs at pH less than 2.5, and the operating range of pH is in the range from 1 to 2. A lower pH requires the use of special bacteria, such as Leptospirillum ferroxidans. To induce reactions, acid-absorbing components in the ore (well known) should be taken into account.

 Acid absorption delays or stops the reaction, which occurs when sulfuric acid is removed.

 Although the bacterial composition of the ore can be determined by microscopy or final dilution (which gives the results closest to the truth), the development of the reaction is best controlled by the rate of dissolution of arsenic or iron in pyrites or the rate of sulfide oxidation that can be calculated.

 Such control is demonstrated by the curves shown in FIG. 4. Other means are also possible, such as measuring pH, determining titratable acidity, reducing the concentration of ferrous iron, absorbing oxygen, carbon dioxide, and so on.

 Despite the fact that all biooxidation efficiency tests should be based on data collection in an active dump, column tests are acceptable for comparison, for example, for ore material biooxidized in a calculated size column. However, data collection should not slow down the process, which may affect the efficiency of the process.

 In order to facilitate the dissolution of metals, iron sulfate can be added to the reagent solution. The iron sulfate introduced at the very beginning may be present in the bacterial fluid in order to establish and increase the redox potential from the very beginning.

 In the case of preliminary acid treatment, it can be interrupted before the final formation of particulates begins. However, it is preferable to carry out preliminary acid treatment and particle formation at approximately the same time in a continuous process, in order to avoid the cost of rebuilding such huge quantities of ore material, which can make the process economically disadvantageous.

 After the ore particles are placed on a suitable impermeable base (including a layer of material to facilitate drainage), forming a mass from 1.52 m thick to about 91.44 m thick, leaching and / or, if necessary, feeding of feed additives can be carried out.

A typical leach solution has the following composition: from 10 to 30 g per liter of total soluble iron (preferably trivalent), from about 0.1 to 10 g per liter of arsenic or arsenous acid salt, from about 30 to 100 g per liter of sulfate. The blade is either sprayed or wetted by drip irrigation of the leach or nutrient solution. The latter contains Fe ⁺³ in an amount of 4 to 30 g per liter; ammonium sulfate (NH ₄ ) ₂ SO ₄ from about 4 g per liter initially to 1 g per liter during the process. Additionally, about 40 ppm of phosphate is added as a nutrient. The addition of nutrients is controlled, changed, increased or decreased depending on the performance of the process. When irrigated with a leach or feed solution, the oxygen concentration in both of them must be in the range of at least between 5 and 2 mg O ₂ per liter of solution.

 The desired pH value is maintained when sulfuric acid is added, so that a pH of 1.6 to 2 is stored in the processing dump, since part of the solution evaporates, it is necessary to maintain moisture balance in the dump by adding during the reaction.

 Since the dump is not reconstructed due to large volumes according to the invention, the shaping of particles and processing described here are constructed in such a way as to increase the efficiency of biooxidative reactions compared to known methods, for example, in a cube with sludge, with liquid washing and inoculation during ore processing biooxidative solutions. In addition, this invention allows the processing of ores with a low sulfide content.

 Also, the present invention differs from typical biooxidative reactions in which a biooxidant solution irrigates the dump with spraying or drip irrigation so that bacterial colonies form over time. Such a known distribution in practice is not effective, takes a lot of time and, in addition, does not give uniform penetration and distribution of the solution in the dump. In such dumps, bacteria are mainly concentrated only from above to a depth of 30.48 cm to 60.96 cm. It is difficult to maintain the same conditions during the process in such dumps, and the reaction proceeds without producing the results that can be obtained by this method.

 The viability of bacteria can only be controlled in the upper part of the dump, and large dead zones form throughout the dump. Therefore, in the known methods for leaching ore used shallow dumps (flat dumps).

 Upon reaching a reasonable equilibrium after the induction period and after the introduction of additional leaching agents during the reaction, the development of the biooxidation reaction is controlled by the necessary marking elements, which directly or indirectly indicate the sulfide oxidation rates and the end conditions of the process. For example, arsenic and iron are used as marking elements that determine the oxidation of sulfides based on the presence of arsenopyrite and pyrite sulfides. Since the rate of the biooxidation reaction depends on the attachment of bacteria to the ore, that is, the substrate, the method of this invention provides a particularly favorable mechanism for overcoming the rate-limiting dependence that is characteristic of prior art leaching processes. Other parameters that illustrate the effective diffusion of the biooxidant, as well as the reaction rate in accordance with the invention, are the amount of other materials found in the solution, as well as the maximum extractability of the target metal, for example gold. Other examples of marking elements can be those elements that are combined with the target metal and which can be controlled for this purpose by the appropriate method for each individual ore type.

 As for the temperature at which optimal activity in the dump is achieved, it depends on the conditions in which the area of the formation of the dump is located. The internal contents of the dump are resistant to temperature changes in the environment and change little, with the exception of the exothermic oxidation of sulfide, as mentioned above.

The biooxidant is recycled at a rate of from 0.0182 L per minute to 0.093 m ^{2 of the} upper surface area of the ore body. Suitable speeds range from approximately 0.0113 L per minute per 0.093 m ² to 0.0378 L per minute per 0.099 m ² .

The preferred rate is from 0.015 to 0.022 l / min / 0.093 m ² .

 The distribution of the leachate can be done by known means used in conventional leaching processes, but drip irrigation is preferred. In addition to drip irrigation, “swing” irrigation or spray irrigation can be used, the latter type of irrigation can increase the oxygen content in the solution, and therefore this method can also be used to control excess solution by increasing fumes.

 Based on experience, the achieved sulfide oxidation is approximately 50 to 60% on a time scale, in terms of process efficiency.

 It is desirable, although not necessary, to obtain the highest possible oxidation state of sulfide. It is also desirable that any elemental sulfur content be oxidized, especially if it takes part in the occlusion of the required amount of metal.

 Since the oxidation of iron (or another selected metal) is correlated with the oxidation of sulfide, the reaction can be easily calculated. It was found that from about 50 to 60 wt. sulfur may remain in the ore, which is permissible.

 However, if the reaction rate is sufficient, higher oxidation of sulfur is contemplated, contributing to further reduction of the metal, such as cyanidation, described below.

With repeated use of the biooxidant, a suspension stream can be created to remove Fe ³⁺ ; Typically, an Fe ³⁺ content of about 30 g per liter in the waste stream is considered the limit. Then the negative effect of iron on the reaction rate, i.e., its inhibition, can begin, and if arsenic ions are present, they also contribute to this inhibition. Since arsenic is a biocide, it is best to ensure that its amount does not exceed approximately 14 g per liter. Biooxidant acts mainly on sulfur pyrites. If the bacteria found an opportunity to adapt, as occurs in nature in ore mines with a high arsenic content, the reaction can begin and proceed with fairly large amounts of arsenic.

Thus, biooxidation helps to remove excess unwanted arsenic. Arsenic can be removed by coprecipitation with iron under suitable conditions. Typically, arsenic in the form of arsenate (As ⁵⁺ ) and iron (Fe ³⁺ will co-precipitate when the ratio in the Fe: As solution exceeds 4: 1 and the pH of the solution exceeds 3. In order to raise the pH of the solution and facilitate co-precipitation, lime is used .

 The resulting ferriarsenate is a very stable compound with very little dissociation ability. In addition, the presence of ferriarsenate and iron arsenates together contributes to the high consumption of cyanide.

 Similarly, in systems where another metal is leached, a slurry stream is also used to remove this metal and recover it. Further, the entire stream after bioleaching can be processed to restore this metal.

 In each of these cases, the reduction of the desired metal occurs directly from the biooxidant stream, the metal reduction is part of the biooxidation / bioleaching stage, and a separate reduction stage becomes unnecessary.

 Appropriate process steps for recovering the desired metal from the bioleach solution include precipitation, solvent recovery and / or ion exchange.

 After the biooxidation reaction has come to an economically feasible end, the dump can be drained and washed several times with water. Typically, a two-week washout period is sufficient. Flushing cycles and time periods are based on the performance of the corresponding marking element, for example iron, and the pH obtained after washing the runoff. The target amount is about 500 ppm Fe in the washing stock.

 Since the inventories for obtaining the solution and its processing make up a significant part of all the costs associated with the leaching of the dump, it is necessary that all the manipulations be carried out as follows. One of the aspects of the pre-oxidation of the dump is the use of a repeated biooxidant solution as an inoculant in the formation of particulates for processing the next portion of ore. The drained solution from the dump to the washing of the latter is acidic and contains bacteria and ferric iron. This solution can then be successfully used to form particles with a recirculating solution, that is, an inoculating ore solution, which enters the processing process. Wash water also contains these bacteria and ferric iron at acidic pH and can be successfully used after washing with a leach in the biooxidation stage to form particles and inoculate bacteria. Thus, solutions are used in the process, while reducing the need for water, until inoculation (the introduction of bacteria) disappears. In the method of the present invention, the creation of a solution is greatly facilitated by accelerating the initiation and leaching stages. Therefore, the method of the present invention requires a smaller volume of solution to restore the same amount as known methods of bioleaching and cyanidation.

 When reusing and recycling the leach agent, it may be necessary to circulate air and carbon dioxide, which can be achieved by introducing an appropriate amount of air or oxygen into the biooxidant solution and directly introducing a certain amount of gases into the dump. With large amounts of oxygen, that is, with those that are significantly higher than the saturation level of 8 mg / liter of solution, oxygen also has an inhibitory effect. Typically, the oxygen content should not exceed 25-50 ppm leach.

 During the process it is necessary to take measures against contamination of the system with excessive biocides, for example biocidal surfactants and so on.

 With regard to the reduction of metal by a separate washing or leaching stage, after subsequent processing and washing of the dump and after the pH is set in the dump, such as during extraction with thiourea, from 1.5 to 20, a thiourea leach is introduced into the dump and processed . Typically, about 0.1 g per liter to 10 g per liter of thiourea is used. The preferred level is from 0.2 to 5 g per liter. Thiourea solutions may contain sulfide, as it improves the effect of leaching of thiourea. Other agents that can be added are sulfuric acid to regulate pH and citric acid to stabilize thiourea.

 Thiourea is not such a favorable reagent as cyanide. Typical for thiourea leaching is that gold reduction does not produce results such as cyanide leaching.

 Although the cost of rebuilding the blade for cyanide is cheaper than using thiourea, thiourea nevertheless has some advantages for environmental reasons.

 Similarly, thiosulfate, ammonium thiosulfate or sodium thiosulfate can be used. Typically, ammonium thiosulfate as a leach operates at a pH level of from 8 to 10, and preferably at pH 9, so the bio-leached ore requires neutralization. With direct neutralization, the process becomes extremely expensive and, moreover, can cause clogging of the blade as a result of the formation of iron hydroxide. Therefore, neutralization can be carried out by other means, for example, destruction of the blade and the introduction of cement or lime, or both, in order to bring pH to the proper level during leaching with thiourea. Gold dissolved in thiosulfate is reduced by cementation or sulphide precipitation. The cost of thiosulfate leaching is lower than thiourea, however, the disadvantages of this method are the need to reconstruct the dump and neutralize. In order to choose one of these methods, it is necessary to evaluate their benefits under certain conditions.

 Cyanization of ore in the dump is also an effective way. Therefore, one of the advantages of the present invention is a strong particulate that allows leaching of the blade and makes it possible not to resort to rebuilding the blade. Rebuilding the blade is possible according to the present invention by adding lime, Portland cement, caustic soda, cement dust or a mixture thereof by thoroughly mixing the ore with a neutralizing agent and then sintering the ore. Due to the relatively high consumption of lime, the neutralization reaction should take place with good contact of the lime with the acid ore material. The ore remains acidic despite being washed and has a pH level of up to 1.5 to 5.

 Neutralization is advisable when using an acid- and alkali-resistant agglomerating agent, and it can be accelerated by destroying the biooxidized dump and rearranging the dump using a conveyor and other similar devices.

 Neutralization and rearrangement by the correct formation of macroparticles, which is facilitated by biooxidation, and their formation from the very beginning unexpectedly turned out to be extremely effective for the subsequent restoration of gold using cyanide. Such stepwise processing and the formation of particulates provide the necessary porosity, good seepage, good access of cyanide ions and proper distribution of the leach solution. It was found that the ratios of voids and surfaces to volume are approximately the same as during biooxidation, but biooxidation alone gives lower values. The rebuilt blade is also aged in the maturing mode for 1-2 days for proper further functioning. After the blade has been treated with a cyanide solution for the required period of time, determined by the limit amount of gold in the leach solution, the blade is washed or appropriate fungi or other microorganisms are introduced that destroy the residual cyanide in the blade.

 In combination with cyanide treatment, appropriate surfactants, oxygen or ozone, or mixtures thereof, can also be added to the leachate, as described in the prior art. As for biooxidation, it is characteristic of cyanidation, that is, leaching and rest cycles during the same time contribute to the extraction of gold. Also, if there is a tendency to clog in the heap, it can be opened.

 Known solutions used for cyanide reduction are leach solutions based on sodium cyanide or potassium cyanide. Gold recovery reaches from 35 to 80 wt. as shown by analysis, including the determination of gold in an alkaline solution by atomic absorption spectroscopy, the flammability test of a leached ore deposit, or the flammability test of carbon used to reduce gold. In cases where the necessary amounts of metal are present as compounds dispersed in the ore or occluded in the matrix of the biooxidant and these compounds are not oxidized, biooxidation has made these amounts more accessible for reduction (at least to some extent, freeing from the matrix material) . Now these compounds lend themselves to further processing and the method of recovery that suits them. Further examples explain the invention, clarifying it, but not limiting its scope.

Example 1. A culture of Thiobacillus ferroxidans or similar microorganisms capable of oxidizing iron and growing under acidic conditions is grown in an acidic nutrient solution. A typical nutritious acid solution contains: 400 mg / L ammonium sulfate [(NH ₄ ) SO ₄ ] 40 mg / L dibasic potassium phosphate (K ₂ NRA ₄ ); 400 mg / l magnesium sulfate hemihydrate (MgSO ₄ • 7H ₂ O); 33.3 g / l of ferrous sulfate hemihydrate (FeSO ₄ • 7H ₂ O) having a pH of from 1.6 to 2, obtained by the addition of sulfuric acid (H ₂ SO ₄ ). The microorganism culture grows from three to ten days with aeration at a temperature of from 20 to 35 ^o C in an amount sufficient to obtain the solution necessary for the formation of particulate matter. The microbial culture solution is used in ore processing for the formation of particulate particles described above.

 Example 2. Two samples (A and B) of 500 tons of crushed ore (nominal size minus 1.89 cm) were used to form particles using a culture solution (example 1) T.ferroxidans. About 19.278 L of culture solution was used to form particulate matter.

 After that, ore samples were placed on asphalt pads for pretreatment with biooxidation to increase gold recovery.

 Sample A contains gold quartz ore, also containing sulfur in the form of sulfide and sulfate. Ore contained by weight 1% iron oxides, 4% jarosite, 10% alunite, 4% kaolinite, 4% sericite, less than 1% pyrite, the rest was essentially quartz (about 73% or more).

 Flammability testing of gold showed a gold content of up to 0.051 g per ton of ore. A gold cyanide test corresponding to 0.012 ounces per ton of ore showed that a significant portion of the gold was in a bound state, i.e., it was occluded in the ore.

 The total sulfur content in ore A was about 1.42 wt. of which sulfur sulfate was about 1.22 wt. and sulfur sulfide about 0.31 wt. The total carbon content was 0.16% which was acid insoluble. The remaining ingredients included 0.666 wt. As and about 2.19 wt. Fe.

 Ore sample B contained, by weight, about 1% iron oxides, 3% barite, 3% jarosite, 12% alunite, 6% montmorillonite, 4% sericite, 2% pyrite, and the rest was quartz (over 65%).

 The amount of gold determined by the flammability test was 0.065 ounces per ton of ore. The cyanide test did not show the presence of free gold, which meant that all the gold was contained in the ore in a bound state. The analysis also showed that the total sulfur content by weight 2.31% while the sulfate sulfur was 1.16% and the sulfide sulfur was about 1.15%. The total carbon content by weight was 1.27% of which 1.21% was acid insoluble. The ore also contained 0.035% As and 2.04% Fe by weight (total).

 Example 3. The formation of particulates from ore particles (according to Example 2) was carried out by adding a bacterial culture to the ore on the conveyor belt, as shown in FIG. 1.

 The culture solution was added in an amount of 60.48 to 75.6 L per 1.67 ton of ore per minute. Two belt conveyors and a dump conveyor were used as transfer points in order to facilitate mixing of ore with the culture solution.

 Inoculation. Effective pre-treatment with leaching or biooxidation requires the presence of an active bacterial population such as Thiobacillus ferroxidans. Recently mined ore usually does not contain a sufficiently large population of bioleaching bacteria. To initiate the rapid action of bacteria and ore processing, it is necessary to inoculate the ore with bacteria, especially in dumps containing a very large amount of solid particles in relation to the leaching solution.

 It is preferable to inoculate the ore with microbes, such as Thiobacillus ferroxidans, during the formation of particulate matter. The advantage is that bacteria can be distributed on the ore particles and layered particles in layers when they enter the biooxidative treatment in the dump. Inoculation accelerates the initiation of active biooxidation.

 Despite the fact that the invention has been described in connection with the preferred options for its implementation, it is clear that other options and modifications are possible without deviating from the essence and scope of the invention, which is clear to specialists. These options should not go beyond the scope of the invention. YYY2 YYY4

Claims (24)

 1. The method of extraction of metals, including the formation of a dump of mineral ores, biooxidation of sulfides and / or sulfur and ferrous iron, which are part of the ores, under the action of a leach solution dispersed in the dump, circulation of the leach solution inside the dump and recovery of metals from the solution, characterized in which is preliminarily formed from ore particles using an inoculating agent containing bacteria capable of oxidizing sulfides and / or sulfur and ferrous iron, the particulate matter from which Twala.  2. The method according to claim 1, characterized in that prior to the formation of particulates, the ore particles are treated with an acidifying solution.  3. The method according to claim 1, characterized in that when the formation of particulates, the ore particles are treated with an acidifying solution.  4. The method according to claim 1, characterized in that after the formation of the particles they are treated with an acidifying solution.  5. The method according to PP. 2 to 4, characterized in that the acidifying solution contains an agglomerating agent and an inoculating agent.  6. The method according to claim 5, characterized in that the sintering agent contains an acid-resistant, bacteria-compatible, water-soluble material based on a vinyl polymer obtained by step polymerization. 7. The method according to claim 6, characterized in that as the vinyl polymer using a polymer, the monomer of which has the General formula
C R
where R is nitrile, amide, carboxyl of the general formula
COOR ₁ ,
where R _{1 is an} alkyl radical containing not more than four carbon atoms.  8. The method according to claim 7, characterized in that the vinyl polymer is either a homopolymer of acrylamide, or a homopolymer of acrylic acid, or a copolymer of acrylamide and at least one monomer other than acrylic acid, or a copolymer of acrylic acid and at least one monomer other from acrylamide, or a cationic or nonionic copolymer of acrylamide and acrylic acid, or a copolymer of acrylamide, acrylic acid and at least one monomer, and the acid resistance of the material is at least three weeks.  9. The method according to claim 6, characterized in that the material based on a vinyl polymer contains polyacrylamide.  10. The method according to claim 6, characterized in that the vinyl polymer material contains a moderately anionic polyacrylamide, cationic polyacrylamide or non-ionic polyacrylamide. 11. The method according to claim 1, characterized in that bacteria are used that are selected from the group of Thiobacillus ferroxidans, Thiobacillus thiooxidans, Thiobacillus organoparus, Thiobacillus acidophilus, Leptospirillum ferroxidans, Sulfobacillus Sulfolobusulfolidusulfolidus sulfolidus sulfolobus sulfolobus sulfolobus sulfolobus sulfolobus sulfolobus sulfolidus
or a mixture thereof.  12. A method for the extraction of metals, including the biooxidation of sulfides and / or sulfur and ferrous iron in an ore body when a solution containing sulfur oxidizing bacteria is dispersed inside the ore body, reduction from a solution of noble metals, characterized in that the particles are first formed from ore particles in the ore body and an inoculating agent containing bacteria capable of oxidizing sulfides and / or sulfur and ferrous iron.  13. A method of extracting metals, including the formation of a dump, biooxidation of sulfides and / or sulfur by the action of an inoculating solution containing bacteria capable of oxidizing sulfides and / or sulfur and ferrous iron, and the recovery of noble metals from the solution, characterized in that the minerals of the dumps are preliminarily ground for the formation of ore particles of predetermined sizes and form from the obtained particles and the inoculating agent, the particles used to form the dump support in the process of biooxidation in favorable conditions for bacterial growth both inside and on the particles, the inoculating agent is continuously circulated inside the dump, and after the restoration of the dissolved excess metal from the solution, the dump of particles is reconstructed with lime, Portland cement, cement, dust particles or sodium hydroxide added to the dump, followed by recovery of precious metals from the dump by cyanidation or treatment of thiosulfate particles.  14. A method of extracting metals, including the formation of a dump, the biooxidation of sulfides in the dump by the action of bacteria and the restoration of noble metals, characterized in that the pre-formed particles having a certain size, surface area and the content of inoculant agent, and biooxidation is carried out for a time sufficient to transfer precious metals in the ore in a state that can be cyanidated or leached with thiourea or thiosulfate.  15. A method of extracting metals, including the formation of a dump, the biooxidation of sulfide under the action of bacteria and the separation of metals, characterized in that it is preliminarily formed from particles of ore, clay, an acid-resistant polymer agglomerating agent and an inoculating agent containing sulfur-resistant bacteria, particulates from which the dump is formed.  16. The method according to p. 15, characterized in that the ore particles are simultaneously treated with an agglomerating agent and an inoculating agent.  17. The method according to clause 16, wherein the particles are pre-treated with an acidifying solution.  18. The method according to clause 16, characterized in that the treatment with an acidifying solution is carried out simultaneously with the treatment with an agglomerating agent.  19. The method according to clause 16, wherein the treatment with an acidifying solution is carried out after treatment with an agglomerating agent.  20. The method according to 14, characterized in that the processing of ore particles is carried out with a solution containing an agglomerating agent and an inoculant.  21. The method according to claim 20, characterized in that the ore particles are pre-treated with an acidifying solution.  22. The method according to claim 20, characterized in that the treatment with an acidifying solution is carried out simultaneously with the treatment with an agglomerating agent.  23. A dump containing particles of sulfide ore material, characterized in that it consists of particulates containing ore body particles having a size of less than 2.5 cm, and a layer of particles containing particles of ore material, clay particles, an acid-resistant polymer aggregation agent and inoculating an agent with sulfur-oxidizing bacteria, the particulate having sufficient strength to maintain at least 95% of the void volume at a column height of 0.183 m for at least 200 days during continuous washing of the column with a solution, consisting of an inoculating agent or its solvent. 24. The blade according to claim 23, characterized in that the core of the blade is made of particles using a bacterial inoculating agent selected from the group of Thiobacillus ferroxidans, Thiobacillus thiooxidans, Thiobacillus thiooxidans, Thiobacillus organoparus, Thiobacillus acidophilus, Leptospulfillidomorphus sulfidophyldus sulfidofloridomidyl sulfide Sulfolobus BC, Sulfolobus solfataricus, Acidanus Brierleyi,
or mixtures thereof.

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