BRPI0701068B1 - NICKEL AND COBALT RECOVERY PROCESS FROM AN ELUTE USING SOLVENT EXTRACTION - Google Patents

Abstract

nickel and cobalt recovery process from an eluate employing solvent extraction and nickel or cobalt containing product obtained by such process. The present invention relates to a process comprising the following steps: (a) beneficiation or preparation of nickel and / or cobalt-containing ore, in addition to other base metals; (b) ore leaching: may occur in various forms and combinations; (c) pulp resin: the product obtained from the leaching is subjected to resin treatment following a countercurrent flow, eliminating the solid-liquid separation step; (d) solvent extraction: the eluate obtained after resin elution is subjected to operation in one or more solvent extraction stages for nickel and cobalt separation and one or more stages for purification of nickel-containing raffinate, if necessary; (e) Nickel electrolysis: The raffinate obtained in step (d) or the effluent solution of the previous nickel-containing stage feeds the electrolysis step to obtain the final product as nickel cathode; and (f) cobalt along with some impurities are contained in the solvent re-extraction solution, which should feed a cobalt recovery precipitation unit.

Description

(54) Title: NICKEL AND COBALT RECOVERY PROCESS FROM AN ELUATE USING SOLVENT EXTRACTION (51) Int.CI .: C22B 3/42; B01D 11/04; C22B 23/00; C22B 3/04; B01J 41/02; B01J 31/08 (73) Owner (s): VALE S.A.

(72) Inventor (s): FLÁVIA DUTRA MENDES

1/24 “NICKEL AND COBALT RECOVERY PROCESS FROM AN ELUATE USING SOLVENT EXTRACTION” [001] The present invention deals with a process for recovering nickel or cobalt from ores or solutions containing them, preferably lateritic ores from nickel, with application in the hydrometallurgical industry.

[002] Hydrometallurgical has become increasingly important in the exploration of nickel deposits. Abundant deposits of high-grade sulphide ore and simple mining are being depleted and environmental legislation is stricter every day, making it difficult to implement pyrometallurgical processes, previously established. The combination of these two factors has been increasing the importance of lateritic deposits, including those with low nickel content, as a source of nickel and cobalt in the world and driving development in hydrometallurgy.

[003] Leaching is a hydrometallurgical process, which uses an aqueous solution, usually acidic, to promote the dissolution of the metals of interest and separate them from the rest of the ore, for later recovery. Several leaching processes have been developed over the years. The most common for nickel laterites is acid leaching under pressure. This has been used to process low magnesium laterites in Moa Bay, Cuba since 1959. With a capacity to process around two million tons of ore a year, it was built by Freeport Sulfur, owner of Nicaro, responsible for the Caron process. This plant was taken over by the Cuban government during the 1960 communist revolution, restarting its operations the following year.

[004] The acid leaching process under pressure has many advantages. It can be applied to low-grade laterites and it is a known process for laterites with which high nickel and cobalt recoveries are obtained, unlike the fusion processes and the Caron process, for example. Metals can be produced individually, adding more value. There are also no drying and roasting steps, which require a lot of energy. Among the disadvantages,

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2/24 pressure leaching is economically viable only if used in limonites that contain low levels of acid-consuming gangue. It also requires a high investment in autoclaves and flash tanks.

[005] Still, the processes for extracting nickel from laterites mentioned above, hydrometallurgical or not, require a large investment and / or large energy expenses. A new, simpler and cheaper method was thus developed: atmospheric leaching which includes leaching in agitated tanks and leaching in batteries.

[006] Leaching in piles is based on stacking ore, received directly from the mine, in piles of different heights. The leaching solution is then introduced at the top of the pile, percolating it to the bottom, where the resulting liquor is recovered. Its main advantage is its low cost and its main disadvantage is the difficulty in treating ores containing clay in the gangue. This clay absorbs the leaching solution, swells and closes the pores of the pile, reducing permeability and increasing acid consumption. Atmospheric leaching processes involve chelating agents to facilitate the dissolution of the metals of interest. In this case, there is a decrease in implantation costs, as there is no need for autoclaves.

[007] The solid / liquid separation step poses major problems for this circuit. Due to the poor settling characteristics of the pulp in the counter-current decantation stage (Counter-Current Decantation-CCD), about 10% of soluble nickel and cobalt are lost in the tailings. To minimize this significant loss, series of at least six large thickeners, with more than 50 meters in diameter for each stage, are used in solid / liquid separations, to achieve the correct sedimentation of the solids and produce a clear overflow. In this way, the capital cost of a simple CCD step, with conventional thickeners, can reach 30% of that of a titanium autoclave, used in high pressure acid leaching (High Pressure Acid Leaching - HPAL). If chlorides are present, as in some lateritic deposits in arid regions, even more expensive thickeners are needed.

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3/24

In addition to capital costs, operating costs are also high, as they include not only energy consumption for each rake, but also flocculants required for sedimentation of fine material. The consumption of flocculants varies from 200 to 800 grams per ton of solids, which increases the total operation cost of the plant by up to 10%.

[008] Another difficulty to be overcome is the recovery of the metals of interest from the resulting solution, or PLS (pregnant leach solution), due to the impurities present and the low concentration of the metal. Ion exchange is an efficient method of overcoming these barriers, it is effective in low concentrations, and the selectivity can be greatly improved by the correct choice of an ion exchange resin. To avoid the high-cost solid-liquid separation step between leaching and recovery and to take advantage of the high recovery and high selectivity properties of ion exchange resins, an interesting option becomes the pulp resin technology applied directly to the leaching effluent.

[009] Ion exchange technology started to be used on a large scale in hydrometallurgy with the exploitation of uranium in the Soviet Union in the 1950s. As the uranium market expanded, innovations in the application of ion exchange were developed. One of the first innovations to be created and applied commercially was the pulp resin process (resin-in-pulp - RIP) for ores containing uranium, offering the advantage of eliminating the solid / liquid separation step. Also created for gold, the pulp resin process evolved from the carbon-pulp (CIP) process, exchanging activated carbon for ion exchange resin, which brought several advantages, as the resin offers greater capacity and loading rate, is more resistant to abrasion and is less likely to be poisoned by organic matter. The first commercial plant to use RIP for Gold recovery was the Golden Jubilee Mine, in South Africa. The industrial operation in this mine served as a basis for analyzing the advantages of RIP over CIP.

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4/24 [010] The mineral industry has shown a deep interest in the use of solvent extraction for metal concentration, separation and purification. There are great challenges for the application of this technology, since no extractant is highly selective for nickel without the co-extraction of other metals. It is very unlikely that a new and commercial extractant will be developed and commercialized to overcome this deficiency. For this reason, the use of the solvent extraction technique directly to the acidic leaching effluent, containing Ni, Co, Cu, Zn, Ca and Mg, is quite limited and with little chance of selective recovery, free of impurities. An interesting alternative is to apply solvent extraction directly to the eluate, that is, the product that is obtained in the ion exchange step with polymeric resins. This product is considered to have a high concentration of nickel and cobalt, but with a low concentration of impurities, but it still needs to have the metals separated. The expectation is that solvent extraction can be successfully applied in this type of product as the eluate obtained from nickel pulp resin operations, given the high concentration of nickel and few impurities.

[011] Industrial experiments on the application of solvent extraction technology directly to the leaching effluent have not been successful, precisely because of the high degree of impurities and the lack of a highly selective extractor for nickel. This obstacle can be solved by inserting a purification stage between ore leaching and solvent extraction, such as the option of ion exchange with resins applied to the leach effluent pulp, which offers the advantage of eliminating the costly solid-liquid separation.

[012] In the conventional process for treating nickel ores (Bulong, Murrin Murrin, Cawse), the solvent extraction units are fed with somewhat impure solutions, mainly in relation to zinc and copper.

Murrin Murrin

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5/24 [013] The sulfuric process uses Cyanex 272 as a selective extractant for cobalt. This is composed of a phosphonic acid that selectively extracts cobalt, plus some impurities such as manganese, magnesium, copper and zinc. The raffinate contains nickel.

Bulong [014] Bulong uses pressure leaching and the effluent is sent to the iron removal step with the addition of lime before the solvent extraction circuit. Bulong tried to avoid nickel precipitation and relixing processes by applying direct solvent extraction. One of the major disadvantages was the passage of the leaching effluent solution in two solvent extraction circuits and the formation of gypsum.

[015] The sulfuric process first uses Cyanex 272 as a selective extractant for cobalt. This is composed of a phosphonic acid that selectively extracts cobalt, plus some impurities such as manganese, magnesium, copper and zinc. The raffinate contains nickel. Bulong also uses a second stage of solvent extraction with nickel selective versatic acid to minimize the concentration of impurities and increase the concentration of nickel. This stage has been shown to be the most critical in plant commissioning due to excessive gypsum precipitation and scaling.

[016] Some critical points can be mentioned:

[017] • The effluent solution from the previous neutralization stage is saturated with calcium after the addition of limestone. This calcium is co-extracted with nickel in the circuit with the versatic acid, particularly in the latter stages. Reducing the organic feed rate and strict pH control reduce gypsum precipitation. In any case, the build-up of gypsum in Ni solvent extraction was detected.

[018] • It was also found that the versatic acid circuit was contaminated with Cyanex which also carries calcium at higher pH in the circuit.

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6/24 [019] · In the first Cyanex circuit, the removal of cobalt and copper is not quantitative. This fact, combined with the low selectivity of the versatic acid in the second stage, may hinder the production of LME nickel within the specifications.

[020] • The concentration of metals in the solvent extraction feed is low, which implies large circuits.

Cawse [021] Cawse produces a mixed precipitate of Ni and Co that is relixed with ammonia. Cawse's ammoniacal solution, product of this leaching, is treated by solvent extraction using LIX 84l, an oxime that selectively extracts nickel. The vast majority of impurities remain in the raffinate and the nickel-rich solution is sent to electrolysis. The process also includes separate sections for copper reextraction, cobalt reextraction and organic regeneration.

[022] Some specific characteristics of this operation can be mentioned:

[023] • Precipitation of nickel and cobalt hydroxide (MHP) and relixing with ammonia provide great selectivity for the metals of interest. Only base metals are sent to the solvent extraction circuit.

[024] • The washing of the loaded and unloaded organic aids in selectivity.

[025] • The only metal that does not meet LME specifications is zinc, which can be removed from the system by ion exchange resins.

[026] • Some transfer of ammonia to the electrolysis system may occur. [027] • The circuit is robust and the cathodes have a good physical appearance.

Goro [028] Goro performs a sulfuric leaching under pressure, followed by removal of impurities such as Fe, AI, Cr, Cu with lime and ion exchange with resins for copper recovery. The product of this purification feeds two stages of solvent extraction, the first with Cyanex 301 for nickel and cobalt recovery and a second stage for the separation of Ni and Co with 308 Alamine.

[029] Some typical characteristics of this type of approach can be mentioned:

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7/24 [030] · It is a direct solvent extraction applied to the purified sulfuric leach effluent.

[031] · Cyanex 301 can be poisoned with copper, therefore the need for an ion exchange step to remove the metal.

[032] · The Cyanex 301 circuit concentrates both Ni and Co, reducing the size of downstream operations.

[033] · There is the potential for cross-contamination of the organic.

[034] One of the techniques most commonly used for the purification of solutions containing nickel, as well as for the separation between nickel and cobalt, is solvent extraction. However, this technique applied to nickel still has some deficiencies such as those mentioned below:

[035] • There is no ideal commercially available nickel extractant as there is for copper.

[036] • The investment cost of solvent extraction technology in nickel hydrometallurgical plants is often 3-6 times higher than those for copper.

[037] · Nickel solvent extraction circuits need to be adapted to the performance of available reagents, which have very limited performance.

[038] • The extractants available are not always suitable for the chemistry of leaching systems.

[039] • Available extractants do not always produce an electrolyte suitable for the metal production route.

[040] • Solvent extraction circuits for nickel are more complex than those for copper and as in the case of uranium, many stages including washing stages are necessary.

[041] • Solutions often contain economical amounts of cobalt and considerable amounts of copper and zinc.

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8/24 [042] The concentration of impurities in the leach effluent solution increases with the type of ore in the leach feed, in the following order: LATERITAS> SULFECTED CONCENTRATES> MATE> HYDROXIDE PRECIPITATE> SULFETATED PRECIPITATE. Removing impurities and recovering nickel and cobalt from this effluent generally requires a staged approach to hydrometallurgical operations - precipitation, selective leaching, and a multi-stage solvent extraction circuit. The use of more than one type of extractant in an integrated hydrometallurgical circuit generally results in contamination of one extractant with another. Olympic Dam (oximes and amines) and Bulong (Versatic acid and Cyanex 272) presented problems with cross contamination. What are observed are highly complex circuits with limited efficiencies, which generates a series of operational problems in the plants.

[043] The problem occurs because the methods of purification, industrially proven, of the effluent solutions of leaching of nickel ores, such as precipitation, selective leaching and solvent extraction, still have operational limitations. Hence the need to evaluate alternative purification methods, such as ion exchange with pulp resin followed by a single solvent extraction stage, so that they can be applied in a technically optimized manner, offering not only economic advantages, but also greater efficiencies. global nickel recovery.

[044] As the reagents are not highly selective for nickel, the addition of an intermediate purification step tends to overcome the deficiencies of commercially available extractants. However, the techniques developed so far, such as precipitation followed or not by bleaching and solvent extraction, still have a number of operational limitations. For this reason, metallurgists should continue to search for flow charts that allow the use of existing and conventional extractants, but incorporating some operations

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9/24 units that can minimize problems and optimize pre-existing unit operations in conventional flowcharts.

[045] Some characteristics of the current technology can be mentioned:

[046] · The development of new extractants is unlikely.

[047] · The market for nickel extractants is small and development costs are high.

[048] · The ideal extractant would be one that loads at pH = 1 and re-extracts at pH = 4.0. [049] · If a new and successful extractor were synthesized in the laboratory, the costs of providing commercial production, pilot tests and other development costs should exceed US $ 5 million.

[050] · For a market of 300 t / year, the reagent must be too expensive to be attractive.

[051] · The extractant Cyanex 272 composed of phosphinic acid makes the design and development of the cobalt solvent extraction circuit simpler than the nickel circuit.

[052] The main commercially available and commonly used cobalt and nickel solvents are:

[053] · D2EHPA [054] It is a non-selective extractant for nickel and cobalt in sulfuric medium. It operates in a narrow pH range, between 3.5 and 4.5 and its molecular form is (C4H9CH (C2Hs) CH2O) 2POOH.

[055] The solvent operates in a hydrogen cycle, as the equation below shows:

4RH + Ni ²⁺ A R2Ní (RH) 2 + 2H + [056] The attached table 1 illustrates the extraction of metals by D2EHPA in sulfuric medium. It is a low-cost and robust extractant, but it does not have selectivity, as shown in Table 1. Careful pH control and washing with solutions of the desired metal to remove impurities may be necessary.

[057] · Versatic acid

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10/24 [058] Another non-selective extractant for nickel and cobalt, which acts in a sulfuric environment and under a slightly milder pH range, but also narrow, between 5.5 and 6.5.

[059] With the molecular formula R3COOH, it is believed that the extracted species are NÍV2.2HV and C0V2.2HV, where V is the cation of the versatic acid.

[060] Addition of pyridine carboxylate esters can increase the pH 50 of Ca / Ni by about 1 to 1.8 units. The addition of nonyl pyridine can reduce the extraction of calcium to very low levels, but both pyridine reagents are not commercially available. Table 2 illustrates the extraction of nickel and calcium by versatic acid in sulfuric medium. Table 2 shows how the extractions of calcium and nickel behave with the pH variation.

[061] · Phosphine acids [062] There are two main phosphine acids used in solvent extraction: Cyanex 272 and Cyanex 301.

[063] Cyanex 272 is a selective extractant for cobalt and nickel, works in a pH range between 3 and 6, in sulfuric or hydrochloric medium. It also extracts manganese, magnesium, zinc and copper.

[064] Its molecular form is illustrated in formula 1 below. It acts selectively for nickel and cobalt in the pH range between 3 and 5. It also starts to extract magnesium, copper, zinc and manganese at pHs below 5, calcium in 5.5 and iron in the range between 1 and 2. Iron stripping can be made with a solution of 100 g / L of sulfuric acid.

R OH

FORMULA 1 - Molecular structure of the Cyanex 272 extractant.

[065] It is a robust reagent, but cobalt can oxidize the diluent. This can be avoided by excluding air and using a sacrificial antioxidant.

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11/24 [066] Cyanex 301, the sulfur analog of Cyanex 272, illustrated in formula 2 below, selectively extracts nickel, cobalt and copper from leached solutions. It is a strong extractant for these and also for zinc, in sulfated solutions. Nickel and cobalt stripping is done with a 6N HCI solution, however iron and copper stripping does not occur quickly and can lead to disulfide formation and loss of loading capacity. If the stripping step is reductive, the reagent can be regenerated.

R O

R-SH

FORMULA 2 - Molecular structure of the Cyanex 301 extractant.

[067] · Cetoxima LIX 84-1 [068] It is a chelating extractant, selective for nickel, copper and cobalt (II) of sulfuric solutions. It works in the narrow pH range between 4 and 5 and has slow kinetics for nickel and cobalt. Its molecular structure is illustrated below.

FORMULA 3 - Molecular structure of the LIX-84 extractant.

[069] Where: R can be a group C9H19 or C12H25 and A in the case of salicylaldoximas corresponding to a hydrogen and in the case of cetoximas groups C6H5 or CH3.

[070] It extracts nickel in pH ranges greater than 4, with stripping performed with a solution of 25g / L of sulfuric acid or with more than 250g / L of ammonia, as the equations below demonstrate.

R ₂ Ni + 2H ⁺ + SO4 ² '-> 2RH + Ni ²⁺ + SO4 ² '

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R2N1 + 2NH3 + 2NH4 + Ni (NH3) 4 ^2- + 2RH R2N1 + 4NH3 + 2NH4 + Ni (NH3) 6 ²⁺ + 2RH [071] A modified version of the extractant, called LIX 87QN is most used in ammonia stripping circuits.

[072] The average extraction time is between three and four minutes, while the stripping time is between six and ten.

[073] This extractant has some operational difficulties. Cobalt (II) can be easily oxidized to cobalt (III) in ammoniacal solutions, and only cobalt (II) can be extracted. In addition, the cobalt (II) already extracted can still oxidize to cobalt (III), making the already slow step of stripping with sulfuric acid very difficult. [074] Despite this, stripping cobalt (III) can be done by a reductive step, using iron or zinc and acid. Either way, the extraction and stripping of cobalt causes reagent degeneration, leading to a reduction in the selectivity between nickel and zinc, an increase in the number of steps for separating the organic phase and a reduction in the nickel transfer capacity.

[075] · Alamine 308 (tri-isooctylamine).

[076] This tertiary amine is used as an ion exchange extractant. To extract CoCl4 ^2- from solutions leached by hydrochloric acid. Nickel does not form chloro-complexes and is not extracted, copper and zinc are healthy, the latter being extracted in lower concentrations of chlorine than cobalt.

[077] As it contains a basic nitrogen atom, it reacts easily with a variety of organic and inorganic acids, forming amine salts, which are capable of undergoing ion exchange reactions, as the equations below show.

[078] · Protonation [079] [R3N] org + [HA] aq θ [R3NH + A ^- ] org [080] · Ion exchange [081] [R3NH + A ^- ] org + [B ^- ] aq θ [R3NH + B ^- ] org + [A ^- ] aq

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13/24 [082] The degree of ion exchange between the anions of A and B is a function of the relative affinity of both with the organic cation and their respective solvation energies.

[083] The regeneration step of the target species can be done by a wide range of solutions of inorganic salts, such as NaCl, Na2CO3 and (NH4) 2SO4. The stripping step reagent depends on the total recovery of the process, but in general basic agents, which reverse the protonation reaction, give better results in a smaller number of stages. The equation below shows the recovery by Na2CO3.

[084] 2 [R3NH + B ^- ] org + [2Na +. + CO3 ^2- ] aq 2 [R3N] org + H2O + CO2 + 2Naaq + + 2B ^- aq [085] In some cases the formation of anionic complexes, and their subsequent extraction, depend on the concentration of this anion, for example, the extraction of cobalt as chloro-complex.

[086] Due to the limitations of the techniques available today and that have become conventional, a flowchart is being proposed with the insertion and rearrangement of unitary operations that can provide a series of advantages. The attached flowchart 1 illustrates the unit operations involved in the invention, which have the following advantages:

[087] · Minimization of operational problems commonly seen at the plants. [088] • Increased process efficiency and increased global nickel and cobalt recoveries.

[089] • Economic gains due to the reduction of capital and operating costs.

[090] For lateritic nickel ores, leaching of the processed ore is being proposed, which may be acidic or basic in nature, such as sulfuric acid, hydrochloric acid or ammonia. This operation can be carried out in pressurized vessels, in agitated tanks under atmospheric conditions, in the form of leach cells, or a combination of two or more types of leach.

[091] The leaching effluent, as obtained in the form of pulp, without any type of solid-liquid separation, is sent to the ion exchange stage with polymeric resins that are applied directly to the pulp. This process, known as

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14/24 pulp resin, is basically an option for purifying the solution with the prospect of effective and selective nickel recovery from the other impurities present in the effluent. With this type of process, it is possible to eliminate the costly solid-liquid separation step and acquire high-efficiency purification. With this, it is expected great gains in terms of economy of the process, at the same time that a simplification of the following steps in the process flowchart is also being proposed.

[092] With the obtaining of a product of the ion exchange stage, known as eluate, of high purity, what is expected is not only the simplification of the following steps, but also a facilitation in the operation of these units, minimizing the problems that came being commonly detected in power plants. With this, a solvent extraction stage is being proposed, with the Cyanex 272 reagent, aiming at the separation of nickel and cobalt. As it is a product, ie an eluate, quite pure and with low concentrations of impurities, the solvent extraction stage dedicated to purifying the solution may or may not be dispensed, depending on each specific type of ore.

[093] With this, what we have is a simplified flowchart, without the possibility of occurring common operational problems when we have very impure solutions.

[094] Once separated, nickel and cobalt are recovered individually. Nickel is sent to the electrolysis unit where it is recovered in metallic form and cobalt can be recovered in several ways, preferably as an intermediate product, such as sulfides, hydroxides, carbonates, etc. If nickel-containing raffinate presents a significant concentration of impurities, a second stage of solvent extraction, using versatile acid, becomes essential.

[095] Below are described some positive results achieved with the invention, as well as some advantages presented:

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15/24 [096] · Increased process efficiency and obtaining high nickel and cobalt recoveries;

[097] · Simplification of the process with the reduction of unitary operations;

[098] · Minimization of operational problems commonly detected in plants of this nature;

[099] · Reduction of investment and operating costs;

[0100] • Less environmental impact - less water consumption and opportunity to recycle water;

[0101] · Lower operating and capital cost;

[0102] · Higher quality of the final products of the process - high selectivity for metals of interest and high separation capacity and high metal recovery efficiency;

[0103] · Less technical and operational risk, due to the optimization of unit operations with respect to operating conditions, reagents, purity of the feed solution.

[0104] For these purposes, a nickel or cobalt recovery process was developed from ores or solutions containing them, comprising the following steps:

(a) beneficiation or preparation of the ore containing nickel and / or cobalt, in addition to other base metals;

(b) ore leaching: it can occur in different ways and combinations;

(c) pulp resin: the product obtained in the leaching is subjected to treatment with resin following a counter-current flow, eliminating the solid-liquid separation step, (d) solvent extraction: the eluate obtained after elution of the resin is subjected to operation in one or more stages of solvent extraction, for separation of nickel and cobalt and one or more stages for purification of raffinate containing nickel, if necessary;

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16/24 (e) nickel electrolysis: the raffinate obtained in step (d) or the effluent solution from the previous step that contains nickel, feeds the electrolysis step to obtain the final product in the form of cathode nickel;

(f) the cobalt together with some impurities are contained in the solvent re-extraction solution, which must feed a precipitation unit to recover cobalt.

Detailed Description:

[0105] Ore: the nickel ore that is being proposed is of the lateritic type that can be treated conventionally by hydrometallurgical techniques.

[0106] Processing / preparation: this step includes operations such as crushing, scrubbing, attrition, magnetic separation, gravity separation and classification of the ore by size. In this stage, an enrichment of the nickel content in the ore is obtained by the simple physical separation of the fine ore particles, which represent a reduced mass of ore, but which incorporate a large part of the nickel contained in the ore.

[0107] Graphs 3, 4, 5 and 6 illustrate the enrichment that can be achieved in nickel contents by reducing mass recovery and concentration of nickel recovery in this finer fraction, usually 100 #. Table 3 illustrates the nickel enrichment factor as a function of the silicon content in the mesh <200 #. Table 4 illustrates the mass recovery as a function of the silicon content in the <200 # mesh. Table 5 illustrates the metallurgical recovery of nickel as a function of silicon content using <200 # mesh. Table 6 illustrates the nickel content in the fraction using <200 # mesh.

[0108] Leaching: leaching of the ore can take many forms, such as in pressurized vessels, in agitated tanks under atmospheric conditions, in the form of leaching piles. Leaching can also occur in the form of combined leaching where two or more of the types listed above can appear in combination. The most commonly used reagents are those of an acidic nature,

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17/24 such as hydrochloric acid or sulfuric acid, or those of a basic nature, such as ammonium salts.

[0109] Pulp resin: the pulp resin operation occurs in a series of pachucas in series, with agitation performed by the injection of compressed air and contact following a counter-current flow. The separation between resin and pulp is carried out by sieving. This type of ion exchange process directly applied to the pulp eliminates the costly step of solid-liquid separation, offering an increase in the recovery efficiency of nickel contained in the leach effluent, given the phenomenon of sorption-leaching, which provides nickel recoveries both the solid phase and the liquid phase. The elution of the resin can be done in more than one stage with acid reagents such as sulfuric acid, hydrochloric acid or ammonia. Elution with sulfuric acid is preferred in this case and can occur in one or more stages, with concentrations that can vary between about 2% to about 15% by weight. The eluate obtained in this step may contain nickel concentrations above 45g / L with low concentrations of impurities. This product as it is obtained, with a high degree of purity, must be sent to a single solvent extraction stage, aiming exclusively at the separation between Ni and Co.

[0110] The attached table 7 represents an example of nickel recovery from the liquid phase over 10 pulp resin contacting reactors.

[0111] The attached table 8 represents an example of elution of the loaded resin using 10% sulfuric acid.

[0112] Solvent extraction: the objective of this step in the flowchart is only the separation between Ni and Co. The solution that feeds this step is already with a high degree of purity, being able to eliminate the need for a second stage of solvent extraction aiming the removal of impurities as can be found in flowcharts of the Bulong and Goro project. The solution that feeds this stage, consisting basically of metallic sulfates, predominantly nickel, in concentrations above 45 g / L, is contacted with the extractant based on compounds of

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18/24 phosphinic acid such as Cyanex 272, which is selective for cobalt and also some impurities, thus providing the separation of Ni and Co.

[0113] Nickel electrolysis: the solvent extraction rate, that is, the effluent solution from the previous step that contains nickel, feeds the electrolysis step to obtain the final product in the form of cathode nickel.

[0114] Cobalt recovery: cobalt together with some impurities are contained in the solvent extraction solution, which must feed a precipitation unit for recovery of cobalt, preferably as an intermediate product, in the form of sulfide, hydroxide, oxide or carbonate.

[0115] The following examples are intended to better elucidate the scope of the invention, and should not therefore be taken for limiting purposes.

[0116] Examples of sulfuric leaching under pressure and atmospheric and the combination of them:

EXAMPLE 1:

[0117] The granulometric fraction between 32 # and 200 # of the laterite nickel sample is composed of 0.81% Ni, 0.15% Co, 20.16% Fe, 2.14% Mg and 3 , 31% AI. This fraction, together with a 96% sulfuric acid solution, fed the Atmospheric Leach (AL) with a temperature of 950C, stirring at 385 rpm and with 33% solids for 6 hours. In AL, 90.4% Ni and 48.0% Fe were extracted, giving rise to an effluent with a concentration of 4.5 g / L of Ni, 51.3 g / L of Fe, 5.4 g / L of AI and 96.3 g / L of residual free acidity, and a residue with 0.10% Ni, 13.50% Fe and 3.06% AI. Part of this liquor formed, together with a 96% sulfuric acid solution, and with another fraction (below 200 #) of the sample (composed of 1.69% Ni, 0.10% Co, 19.70% Fe, 2.97% Mg and 3.06% AI), fed an autoclave to perform Pressure Leaching (HPAL): at a temperature of 2500C, agitation of 500 rpm, pressure of 650 psi, with 30% solids for 75 minutes. When feeding HPAL, the liquor was diluted and acquired the concentrations of 0.03 g / L of

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Ni, 0.31 g / L Fe and 0.03 g / L AI. After HPAL, the autoclave effluent showed 12.6 g / L of Ni, 14.5 g / L of Fe and 4.6 g / L of AI. And, the residue presented 0.13% Ni, 23.40% Fe and 2.61% AI. Precipitation of Fe and AI regenerated about 116.1 kg / t of acid, which represents 30% of crude consumption. 65.5 kg / t of acid (17% of global consumption) was taken advantage of the residual free acidity present in the effluent of LA, requiring the addition of only 53% (205.4 kg / t) of acid. The extraction of Ni (AL followed by HPAL) was 93.7%, and it may be noted that in Leaching under Pressure the extraction was 95.9% Ni for a crude acid consumption of 387.1 kg / t.

TABLE 1 - Data on sample composition and LA products:

Atmospheric Leaching - AL Composition Ni Co Faith Mg Al (%) (-32 # 0.81 0.15 20.16 2.14 3.31 Liquor / Ni Faith Al Acidity Effluent 4.5 51.3 5.4 96.3 Composition Ni Faith Al of the Residue 0.10 13.50 3.06 Extraction (%) Ni Faith 90.4 48.0

TABLE 2 - Sample composition data and HPAL products.

Pressure leaching - HPAL Composition Ni Co Faith Mg Al (%) (-200 #) 1.69 0.10 19.70 2.97 3.06 Dilution Ni Faith Al (g / L) 0.03 0.31 0.03 Liquor / Ni Faith Al Effluent 12.6 14.5 4.6 Composition Ni Faith Al

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of the Residue 0.13 23.40 2.61 Extraction (%) Ni 93.7

TABLE 3 - Comparison of results between HPAL and AL followed by HPAL.

HPAL AL followed by HPAL Gross Consumption (Kg / t) 387.1 387.1 Regenerated Acid (Kg / t) 0 116.1 Added Acid (Kg / t) 387.1 205.4 Harnessed Acid (Kg / t) 0 65.5 Ni extraction (%) 95.9 93.7

EXAMPLE 2:

[0118] To perform the LA, a fraction between 32 # and 200 # was fed with: 0.36% Ni, 0.09% Co, 22.92% Fe and 0.57% Mg; and a 96% sulfuric acid solution. The operational variables used were: temperature of 950C, agitation of 385 rpm, 33% solids for 6 hours. In Atmospheric Leaching, a liquor with a concentration of 1.7 g / L of Ni, 66.0 g / L of Fe was produced and a residual free acidity of 90.4 g / L. The residue presented 0.06% Ni and 16.80% Fe, with the extraction of Ni being 86.4% and that of Fe was 40.4%. The subsequent step (HPAL) was fed with part of this liquor, a 96% sulfuric solution and a mass of ore corresponding to the fraction below 200 # (0.68% Ni, 0.11% Co, 23.70% Fe and 0.58% Mg). Due to the addition of the solution to the liquor, a dilution occurred and the feed changed to 0.02 g / L of Ni and 0.58 g / L of Fe. Pressure Leaching was carried out at 2500C, 500 rpm agitation , 650 psi pressure, with 30% solids for 75 minutes. The liquor produced obtained 4.5 g / L of Ni and 8.0 g / L of Fe and the residue presented 0.05% of Ni and 26.50% of Fe. Within the autoclave there was regeneration of 88.8 Kg / t of sulfuric acid, equivalent to 30% of gross consumption. For this reason, the mass of acid to be added to the autoclave was 51% smaller, that is,

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144.0 Kg / t were fed and 63.3 Kg / t (21% of gross consumption) were used from LA. The extraction of Ni for a single stage of HPAL was 94.5% and in AL followed by HPAL was 93.1%.

TABLE 4 - Data on sample composition and LA products.

Atmospheric Leaching - AL Composition (%) (-32 # Ni Co Faith Mg 0.36 0.09 22.92 0.57 Liquor / Effluent (g / L) Ni Faith Free Acidity 1.7 66.0 90.4 Composition of the Residue Ni Faith 0.06 16.80 Extraction (%) Ni Faith 86.4 40.4

TABLE 5 - Sample composition data and HPAL products.

Pressure leaching - HPAL Composition (%) (-200 #) Ni Co Faith Mg 0.68 0.11 23.70 0.58 Dilution (g / L) Ni Faith 0.02 0.58 Liquor / Effluent (g / L) Ni Faith 4.5 8.0 Composition of the Residue Ni Faith 0.05 26.50 Extraction (%) Ni 93.1

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TABLE 6 - Comparison of results between HPAL and AL followed by HPAL.

HPAL AL followed by HPAL Gross Consumption (Kg / t) 296.1 296.1 Regenerated Acid (Kg / t) 0 88.8 Added Acid (Kg / t) 296.1 144.0 Harnessed Acid (Kg / t) 0 63.3 Ni extraction (%) 94.5 93.1

EXAMPLE 3:

[0119] The composition of the fraction (-32 # + 200 #) that feeds LA is 0.56% Ni, 0.03% Co, 27.65% Fe, 1.65% Mg and 5 , 10% AI. This fraction was added to a 96% sulfuric acid solution and leached at a temperature of 950C, stirring at 385 rpm and with 33% solids for 6 hours. The effluent of AL presented 91.7% of Ni extraction and 56.6% of Fe extraction, with concentrations equal to 2.6 g / L of Ni, 74.7 g / L of Fe, 14.2 g / L of AI and 65.9 g / L of free acidity. The residue was characterized by 0.07% Ni, 18.10% Fe and 3.39% AI. Part of this liquor together with a 96% sulfuric solution and the fine fraction (-200 #) of this sample was fed into the autoclave for HPAL. The composition of the fine fraction is 1.13% Ni, 0.03% Co, 24.90% Fe, 3.10% Mg and 6.77% AI. The concentration of the liquor that fed the HPAL was 0.01 g / L of Ni, 0.30 g / L of Fe and 0.06 g / L of AI, due to the dilution promoted by the sulfuric solution. The operational parameters used at HPAL were: 2500C temperature; agitation of 500 rpm; 650 psi pressure; and 30% solids for 75 minutes. This leaching obtained a liquor with 7.3 g / L of Ni, 12.1 g / L of Fe and 13.0 g / L of AI and a residue with 0.06% of Ni, 27.80% of Fe and 5.55% AI. During HPAL there was regeneration of 30% acid (144.5 Kg / t), taking advantage of 43.0 kg / t (9%) from free acidity and it was necessary to add 61% virgin acid which corresponds to 294.3 Kg / t. The liquor generated by this Pressure Leach

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23/24 obtained an extraction of 94.8% of Ni and HPAL not preceded by AL obtained 92.6%. It was also observed that 54.6% Fe and 35.3% AI were precipitated.

TABLE 7 - Data on sample composition and LA products.

Atmospheric Leaching - AL Composition Ni Co Faith Mg Al (%) (-32 # 0.56 0.03 27.65 1.65 5.10 Liquor / Ni Faith Al Acidity Effluent 2.6 74.7 14.2 65.9 Composition Ni Faith Al of the Residue 0.07 18.10 3.39 Extraction (%) Ni Faith 91.7 56.6

TABLE 8 - Sample composition data and HPAL products.

Pressure leaching - HPAL Composition Ni Co Faith Mg Al (%) (-200 #) 1.13 0.03 24.90 3.10 6.77 Dilution Ni Faith Al (g / L) 0.01 0.30 0.06 Liquor / Ni Faith Al Effluent 7.3 12.1 13.0 Composition Ni Faith Al 0.06 27.80 5.55 Extraction (%) Ni 94.8

TABLE 9 - Comparison of results between HPAL and AL followed by HPAL.

HPAL AL followed by HPAL Gross Consumption (Kg / t) 481.8 481.8

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Regenerated Acid (Kg / t) 0 144.5 Added Acid (Kg / t) 481.8 294.3 Harnessed Acid (Kg / t) 0 43.0 Ni extraction (%) 92.6 94.8

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Claims (16)

1 - NICKEL AND COBALT RECOVERY PROCESS FROM AN ELUATE USING SOLVENT EXTRACTION including the step of processing or preparing the ore containing nickel and / or cobalt; the ore leaching stage; treatment of the solution obtained in the leaching step with an ion exchange resin; extraction of metals from the eluate by solvent; and electrolysis, characterized by employing a pulp resin with a countercurrent flow in said treatment step of the solution obtained in the leaching step, in which said resin is, preferably, a polymeric resin. 2 - PROCESS, according to claim 1, characterized in that the ore is lateritic. 3 - PROCESS, according to claim 1, characterized in that the ore beneficiation or preparation stage may include operations such as crushing, scrubbing, attrition, magnetic separation, gravity separation or classification of the ore by size. 4 - PROCESS, according to claim 1, characterized in that the ore leaching step can take different forms, such as in pressurized vessels, in agitated tanks under atmospheric conditions or in the form of leach piles. 5 - PROCESS, according to claim 1 or 4, characterized by being able to employ various forms where two or more types of leaching are combined. 6 - PROCESS, according to claim 1, characterized in that the pulp resin operation can take place in a series of pachucas in series, with agitation performed by the injection of compressed air and contact following a countercurrent flow. PROCESS, according to claim 1, characterized in that the separation between resin and pulp can be carried out by sieving. PROCESS, according to claim 1, characterized in that acidic reagents are used in leaching such as hydrochloric acid, or sulfuric acid or those of a basic nature such as ammonium salts. PROCESS, according to claim 6, characterized in that sulfuric acid is preferably used. Petition 870170082253, of 10/26/2017, p. 32/43 2/2 10. PROCESS, according to claim 7, characterized in that the elution occurs in one or more stages, in concentrations that can vary between about 2% to about 15% by weight. 11. PROCESS, according to claim 1, characterized in that the solution that feeds the solvent extraction step can be basically constituted by metal sulfates. PROCESS, according to claim 11, characterized in that the solution may contain more than 45 g / L of nickel. PROCESS, according to claim 1, characterized in that it can use phosphinic acid compounds as an extracting agent. 14 - PROCESS, according to claim 1, characterized in that the solvent extraction stage occurs in a single solvent extraction stage for the separation of nickel and cobalt, and a second stage may also occur for the purification of nickel-containing raffinate. 15 - PROCESS, according to claim 1 or 14, characterized in that a second solvent extraction step can be used, using versatile acid, for purifying the raffinate obtained in the previous step. 16. PROCESS according to claim 1, characterized in that cobalt is preferably obtained in the form of an intermediate product, such as in the form of sulfide, hydroxide, oxide or carbonate. Petition 870170082253, of 10/26/2017, p. 33/43 1/9 ore Ni cathode FIGURE 1 Petition 870170082253, of 10/26/2017, p. 35/43 2/9% Extraction PH FIGURE 2 Petition 870170082253, of 10/26/2017, p. 36/43 3/9 FIGURE 3 Petition 870170082253, of 10/26/2017, p. 37/43 FIGURE 4 Petition 870170082253, of 10/26/2017, p. 38/43 5/9 FIGURE 5 Petition 870170082253, of 10/26/2017, p. 39/43 6/9 FIGURE 6 Petition 870170082253, of 10/26/2017, p. 40/43 7/9 Ni content (%) FIGURE 7 Petition 870170082253, of 10/26/2017, p. 41/43 8/9 Nickel extraction (%) Stages FIGURE 8 Petition 870170082253, of 10/26/2017, p. 42/43 9/9 FIGURE 9 Petition 870170082253, of 10/26/2017, p. 43/43