KR101403209B1 - Method for recovering nickel from ni ore - Google Patents

Abstract

The present invention provides a method for recovering nickel and cobalt from nickel ore that contains Co, Ni, and Fe. The method of the present invention includes a reduction step in which the ore containing Co, Ni, and Fe is reduced with hydrogen-containing gas so that reduced ore for leaching is obtained; a leaching step in which the reduced ore is dissolved with acid so that Ni, Co, and Fe ions are leached and a solid is removed through a solid-liquid separation so that leachate containing the Ni, Co, and Fe ions is obtained; an extraction step in which reduced ore for extraction, which is obtained by reducing the ore containing Co, Ni, and Fe with the hydrogen-containing gas, is put into the leachate, the nickel and the cobalt in the leachate is substituted with iron in the reduced ore for extraction, and an extract from which Ni and Co are extracted is obtained; a re-leaching step in which the extract is dissolved with the acid and the nickel and the cobalt are re-leached so that re-leachate is obtained; a sludge formation step in which a divalent iron ion in the re-leachate is oxidized into a trivalent iron ion and then a solid iron compound of iron oxide or iron hydroxide is formed and formed into sludge; and an iron removal step in which the solid is removed through a solid-liquid separation so that a Ni- and Co-containing solution containing Ni and Co is obtained.

Description

Method for Recovering Nickel From Ni Ore

The present invention relates to a method for effectively recovering nickel from a nickel-containing ore, and more particularly, to a nickel concentrate obtained by leaching and concentration of nickel or iron-containing ores in a dry reduction process, And a method for separating and recovering nickel.

The ores containing nickel and iron have ores such as limonite and saprolite. These ores have a passive nature and therefore have high acid resistance, so the dissolution reaction to the acid is slow. As a method for effectively leaching nickel, there have been proposed methods for recovering nickel by dissolving in an acid in an autoclave under high temperature and high pressure, which is called 'HPAL (High Pressure Acid Leaching) method'.

When the nickel leaching reaction is carried out at room temperature, the nickel recovery rate does not exceed 85% even after leaching for several months or longer. However, when the HPAL method is used, leaching of nickel at 90% or more is possible within 2 hours, .

Examples of techniques for recovering nickel by the HPAL method include Korean Patent Laid-Open Publication No. 2007-7020915 and Japanese Laid-Open Patent Publication No. 2010-031341.

Examples of techniques for recovering nickel by the HPAL method include Korean Patent Laid-Open Publication No. 2007-7020915 and Japanese Laid-Open Patent Publication No. 2010-031341. However, it is known that the HPAL method should be performed under high temperature and high pressure of the autoclave, and it is known that only the titanium material can be mainly used due to its strong acidity, and accordingly, the equipment cost is very high and the maintenance cost is high.

On the other hand, the present inventors have proposed a method of recovering nickel by acid leaching after reducing the nickel-containing raw material in Korean Patent Publication No. 2009-0031321. In the technique of the patent document, V and Mo are recovered from a petrochemical desulfurization spent catalyst and the remaining residue is treated with an acid to remove alkali elements in the residue; Drying the residue from which the alkali element has been removed, and then performing a heat treatment in a reducing atmosphere at a temperature range of 600-1300 캜 to reduce Ni and Fe existing in an oxide form in the residue to a metal; Leaching the reduced product obtained in the above step with an acid to selectively dissolve iron and nickel; Filtering the solution to obtain leached nickel and iron ion-containing solution; Neutralizing the solution containing Ni and Fe ions with alkali to make Fe and Ni hydroxide; And a step of filtering and drying the product obtained in the above step to obtain Fe and Ni-containing raw materials, and a method for producing iron nickel-containing raw materials from petrochemical desulfurization spent catalyst recycled residues.

However, this method has a disadvantage of not recovering Co in ore.

The present invention seeks to provide a method for separating and recovering nickel and cobalt from a raw material containing nickel, iron and cobalt, in particular, nickel having a low nickel content.

Further, it is intended to provide a method of recovering high-purity nickel and cobalt in a single or mixed form.

The present invention provides a method for recovering nickel and cobalt from nickel ores containing Co, Ni and Fe. The method of the present invention reduces ore-containing ores containing Co, Ni and Fe to hydrogen- Lt; / RTI > Leaching step of dissolving the reduced light in an acid to leach out Ni, Co, and Fe ions, and removing solids by solid-liquid separation to obtain an leach solution containing Ni, Co, and Fe ions; A precipitating step of adding precipitate reducing light obtained by reduction with hydrogen-containing gas into the above-mentioned leaching solution to replace nickel and cobalt in the leaching solution with iron in the precipitation reducing light to obtain a precipitate in which Ni and Co are precipitated; A re-leaching step of dissolving the precipitate in an acid to re-leach nickel and cobalt to obtain a re-leach solution; A sludge forming step of oxidizing dihydric iron ions in the re-leach solution to trivalent iron ions, forming a solid iron compound of iron oxide or iron hydroxide to sludge; And an iron removing step of removing the solid content by solid-liquid separation to obtain Ni and Co containing solution containing Ni and Co.

The leaching reduction light and the precipitation reducing light may be reduced at a temperature of 725-950 ° C, and the precipitation reducing light preferably has a Fe reduction ratio of 75-95%.

The acid in the leaching step and the leaching step may be independently sulfuric acid or hydrochloric acid.

The precipitation step may be carried out at 70-100 < 0 > C.

Further, an oxygen-containing gas may be injected into the re-leaching solution to cause oxidation reaction of the divalent iron ions with the trivalent iron ions. At this time, the oxidation reaction may be performed by further supplying an oxidizing agent together with the oxygen-containing gas, and hydrogen peroxide may be used as the oxidizing agent. The hydrogen peroxide may be supplied in a range of 10-100% of the oxygen equivalent ratio required for the oxidation of the divalent iron ions.

Further, the iron oxide may be formed by thermally hydrolyzing the re-leaching solution containing the trivalent iron ions at a temperature of 100 to 250 ° C or more.

Further, the iron hydroxide can be produced by introducing an alkali agent into the re-leaching solution containing the iron oxide. At this time, it is preferable that the alkaline agent is added so that the pH of the re-leachate is 1.5 to 4.5, and the alkaline agent may be calcium, sodium, magnesium, iron or manganese hydroxide or a mixture of two or more thereof.

Further, the nickel and cobalt recovery method of the present invention may further comprise a separation and recovery step of separating and recovering nickel and cobalt by solvent extraction of the nickel and cobalt-containing solution.

According to the present invention, since nickel and cobalt can be effectively concentrated from a raw material such as nickel or cobalt-containing ores and the concentrate can be re-leached to separate nickel and cobalt, It is possible to separate and recover high purity nickel and cobalt in addition to conventional ferronickel production.

The present invention relates to a method for recovering nickel and cobalt contained in a concentrate after recovering nickel and cobalt concentrate from ores containing nickel, iron and cobalt. According to the present invention, Nickel and cobalt can be recovered by passing through the step of leaching of the reducing light, the step of nickel precipitation, the step of re-leaching of the precipitate, the step of iron ion oxidation in the re-leaching solution and the step of removing iron.

Hereinafter, the present invention will be described in detail.

The nickel, iron and cobalt-containing raw materials to which the present invention can be applied are not particularly limited, and any materials containing nickel, iron and cobalt may be used, and preferably nickel ores such as limonite, Nickel ores such as prolite.

Nickel ore, such as limonite or saproproite, varies depending on the type of ore, but usually contains 1-2.5% of Ni, 15-55% of Fe, and 0.01-0.15% of Co. Among the limonite ores, the nickel concentration is as low as 1-1.8%, the iron concentration is as high as 30-55%, and Co is contained as 0.05-0.15%.

In recovering nickel from the nickel ore, a pretreatment step may be carried out if necessary in order to effectively reduce the nickel ore in the following reduction process. Such a pretreatment step includes a drying step, a pulverizing step and a baking step. Hereinafter, the pretreatment step will be described in detail.

Nickel ore, a raw material used for nickel recovery, is preferably an atomized powder for efficient reduction and a smooth leaching process. Therefore, it is preferable that the nickel ore is previously pulverized and applied to the nickel recovery process.

At this time, nickel ore, which is a raw material in general, generally contains about 30 to 40% of adhesion water and about 10% of crystal water. In the case of pulverization in the state containing such water adhesion water, Further, when the nickel ore is pulverized after firing, there is a fear that the pulverizing equipment may be loaded due to the high temperature. Therefore, it is preferable to dry the nickel ore before pulverizing the nickel ore into fine particles. There is no particular limitation on the condition that the adhesion water in the nickel ore can be evaporated in performing the drying process for the nickel ore. For example, the heating may be performed at a temperature ranging from 100 to 200 ° C.

When the nickel ore is pulverized after it is dried, it is not necessarily limited to this, but pulverizing the particle size to 1 mm or less is preferable for improving the reduction and leaching efficiency. The lower the particle size of the pulverized ore is, the smaller the particle size of the pulverized ore is, so that the reduction and leaching efficiency can be improved. However, in order to obtain a powder having a particle size smaller than 10 탆, a pulverization step is required to be carried out for a long time or a plurality of times more than necessary, and it is more preferable to use a powder having a particle size of 10 탆 or more.

On the other hand, the number of crystals contained in the nickel ore is not removed in the above drying process. In the reduction process of nickel ore, the number of crystals contained in the ore is released as moisture in the ore during the reduction process, and this moisture slows down the reduction reaction and acts as a factor to lower the reaction efficiency. Therefore, it is preferable to perform the reduction treatment after removing the crystal water. In order to remove such crystal water, it is preferable to calcine the nickel ore.

Among the nickel ores, the limonite ore has a characteristic of emitting crystal water at about 250-350 ° C and the saprophorite ore at around 650-750 ° C. Accordingly, the nickel iron-containing raw material powder obtained in the pulverizing step can be subjected to a calcination treatment at a temperature in the range of 250-850 DEG C to remove the crystal water contained in the raw material.

On the other hand, saprophylite ores having a high nickel content are mainly used as a raw material for dry smelting. The present invention is also applied to a rotary kiln dust generated in a dry smelting process using the saprophite ore, Can be recovered. However, since the dust is contained in a range suitable for applying the present invention to the particle size and is exposed to a high temperature state during the dry smelting process, there is no need of a crushing and firing treatment process as in nickel ore. However, if the particle size is out of the range required in the present invention due to the fact that the dust is exposed to the air and contains moisture, it may be subjected to grinding or baking treatment if necessary. In the present invention, the term "nickel ore" includes the above-mentioned rotary kiln dust unless otherwise specified.

The present invention includes a step of reducing the pretreated nickel ore as described above. This reduction step can be performed at a temperature range of 725-950 DEG C using a reducing gas containing hydrogen as a reducing agent. When the reduction temperature is less than 725 DEG C, the reduction does not sufficiently take place, and the recovery rate upon leaching into the acid solution in the subsequent step is low and the precipitation yield is also lowered. On the other hand, the higher the reducing temperature, the higher the leaching yield and the precipitation yield. However, in the case of reduction at a temperature exceeding 950 占 폚, there is no problem in reducing nickel ore, however, no further increase in reduction efficiency can be obtained, and rather, intergranular sintering may occur and adversely affect workability, Lt; 2 > / g or less, which may lead to a decrease in precipitation yield. Therefore, it is preferable to perform the reduction process in the temperature range as described above.

In particular, the reducing light (precipitation-reducing light) used in the precipitation reaction is preferably adjusted so that the iron reduction rate becomes 75-95%. When the iron reduction rate is low, it is difficult to precipitate nickel and cobalt during the precipitation process after leaching. In particular, since cobalt is not easy to obtain the precipitation recovery rate when precipitating compared with nickel, it is necessary to sufficiently reduce the reduction rate. 75% or more. For this, it is preferable to perform reduction in the temperature range as described above.

As the reducing gas, a gas containing hydrogen may be used. In the case of carbon reduction using carbon as a reducing gas, it is necessary to reduce nickel at a high temperature of 1000 ° C or more, usually 1250 ° C or more to obtain nickel as a metal. In the case of performing the reduction process at such a high temperature, The leaching rate is rapidly lowered, and in particular, there is a problem that the precipitation efficiency in the precipitation step sharply decreases.

However, when the hydrogen-containing gas is used as the reducing gas as in the present invention, the reduction process can be performed at a lower temperature than the carbon reduction. In addition, nickel metal having a specific surface area of 1-100 m 2 / g can be produced with a high activity, whereby it can be easily dissolved by an acid, so that a subsequent acid leaching process can be carried out at high speed.

As such a reducing gas, a gas containing hydrogen can be used. Hydrogen can be used alone, or an inert gas can be used together. The inert gas may be included to remove oxygen other than hydrogen present in the reducing furnace during the reduction reaction. Such an inert gas is not particularly limited as long as it is not reactive, and examples thereof include helium, argon, carbon dioxide, nitrogen and the like.

Further, another example that can be used as the hydrogen-containing reducing gas is a gas generated from a coke oven gas (COG) containing 50% or more of hydrogen generated in the iron ore smelting process or a methane hydrogen reforming reaction, And hydrogen-containing LNG reforming gas containing 65% or more of hydrogen.

By the reduction using such a reducing gas, hydrogen reacts with the oxygen of nickel, iron and cobalt present in an oxidized state in the reduced light to generate water, thereby reducing the nickel, iron and cobalt. At this time, the amount of hydrogen included in the reducing gas may be included in an amount equal to or greater than the theoretical equivalence ratio, and hydrogen is preferably supplied in excess of the theoretical equivalence ratio for efficient reduction reaction. However, such hydrogen is expensive, and the higher the equivalence ratio of hydrogen is, the higher the cost of the process. For example, the amount of hydrogen may be included in the molar amount such as 1 to 5 times, 2 to 5 times, or 2 to 4 times the theoretical equivalence ratio.

The nickel ore reduced by this reaction can be obtained. The reduced nickel ore is hereinafter referred to as a 'reduced light'.

The exhaust gas obtained in the reduction step is discharged and separated, and then the reduced light is slurried using water. It is preferable that the slurrying proceeds in an oxygen-free state in which the inflow of external air is blocked in order to prevent the reducing light from being reoxidized by oxygen. Reduced light obtained by reducing nickel ore has high activity and has a very high iron content. Therefore, in the case of extraction into the air after reduction, the reductant of the reducing raw material is reoxidized, and the oxidation reaction is more likely to occur Accelerated to have a fire hazard. Therefore, oxidation and ignition can be prevented by slurring the reduced light with water.

Water may be added to the slurry so that the slurry concentration is 1-2 times the weight of the reduced light. When the content of water is out of the above range, if it is too small, the concentration of the slurry may be high, which may cause transfer problems. If the water is administered in too much amount, the concentration of the solution after dilution becomes undesirably low.

And a leaching step of dissolving the nickel, iron, and cobalt contained in the reducing raw material in the slurry into an ion by leaching the slurry, adding an acid to the slurry, and leaching into the ion. Reduction light used in the leaching step is also referred to as 'leaching reduction light'. The leaching step may dissolve the reduced light by adding an acid to the slurried reduced light in an anaerobic reactor and stirring the same. As described above, in the case of slurrying, the oxidation of the reduced light is not likely to occur, but when the solution is vigorously stirred in an oxygen atmosphere, for example, in the atmosphere, the reduced light in the slurry may be oxidized by a kind of hydration reaction. Thus, the leaching step is preferably carried out in an oxygen-free state.

The acid used in the leaching step is not particularly limited, but hydrochloric acid or sulfuric acid can be used.

Generally, when the reduced light reduced by the reduction reaction is leached into an acid, nickel, iron and cobalt of the reduced light react with the acid to dissolve and leach into the ions. When hydrochloric acid is used as an acid in order to leach such reduced light into an acid, it is preferable to add hydrochloric acid at a molar ratio of 2 or more times the number of moles of (Fe + Ni + Co). However, in the case where hydrochloric acid is added in excess of 4 times the number of moles of (Fe + Ni + Co), further improvement in leaching efficiency can not be obtained. It is preferable to inject it. On the other hand, when sulfuric acid is used to carry out the leaching reaction, it is preferable to be charged at a molar ratio of at least 1 and at most 2 times the number of moles of (Fe + Ni + Co) of the nickel iron-containing raw material.

Such a leaching reaction is an exothermic reaction accompanied by an increase in temperature in the reactor. Therefore, an acid leaching reaction can be carried out at room temperature, and a leaching efficiency can be obtained at a temperature of 20 ° C or higher. Further, this leaching reaction may be carried out by heating in an appropriate range. In the case of performing by heating, the leaching rate can be improved and the leaching time can be shortened. At this time, the temperature during heating can be appropriately set according to the conditions of the reactor, and is not particularly limited. However, if the temperature of the leaching reaction exceeds 80 ° C, the cost of equipment for the leaching reaction may increase.

When the metal is present in the aqueous solution during the leaching reaction, the oxidation reduction potential (ORP) shows a minus value. If the metal is completely dissolved in the acid, the ORP is changed to zero after the ORP is zero. Therefore, the acid dissolution reaction can be stopped when the ORP is 0 or more, and thus the end point of the acid dissolution reaction can be confirmed by measuring the ORP.

On the other hand, Al ₂ O ₃ , SiO ₂ , and Cr ₂ O ₃ contained in the nickel ore hardly dissolve by the acid, and can be obtained as a solid residue. Therefore, the nickel, iron and cobalt ion-containing solution (leach solution) obtained by the leaching step and the solid residue can be easily separated by filtration, and can be separated by a solid-liquid separator such as a filter press or a decanter, And a solution containing cobalt ions can be obtained.

Next, the step of precipitating nickel, iron and cobalt ions dissolved in the reaction of the formula (2) or (3) as a metal. The precipitation of the nickel, iron and cobalt ions can be carried out by introducing the reducing light as described above. In order to distinguish the reduction light used at this time from the reduction light used in the leaching reaction, it is referred to as " precipitation reduction light ". As described above, it is preferable that the precipitation-reduced light has an iron reduction rate of 75-95%.

When the precipitation-reduced light is introduced into the leaching solution containing iron and nickel ions, a precipitate in which nickel ions and some cobalt ions in the leaching solution are substituted by Fe metal in the precipitation-reducing light to obtain nickel and cobalt precipitates can be obtained . This can be expressed by the following equation (1).

Nickel ions are more easily precipitated by the reduced iron metal, but cobalt is slow in precipitation reaction. Therefore, in order to increase the precipitation recovery rate of Co, it is preferable to set the temperature at the precipitation reaction to 70-100 캜. At a temperature below 70 ° C, the recovery rate of the Co precipitation is less than 40%. When the temperature exceeds 100 ° C, the Fe, Al, and Cr hydrolyzes due to the hydrolysis of the Fe, Al, Cr and the like rather than the reaction in which the recovery rate of the cobalt increases. Can be reduced.

The solid obtained by concentrating nickel and cobalt can be recovered by recovering the nickel obtained by the above precipitation reaction and the precipitate in which Co is concentrated by solid-liquid separation. The solid-liquid separating means may be suitably used in the present invention as long as it is conventionally used for separating solid and liquid such as, for example, filtration, and is not particularly limited in the present invention.

And then re-depositing the recovered precipitate with an acid. The re-leaching step may be carried out using an acid such as hydrochloric acid or sulfuric acid, as in the leaching step, and is not specifically described here.

Nickel and cobalt in the precipitate are dissolved by the re-leaching step, and some of the iron contained in the precipitate is dissolved and incorporated into the re-leachate. Nickel and cobalt can be recovered by removing iron ions contained in the re- have. The iron ion mixed in the re-leach solution is a bivalent ion. The re-leaching solution is oxidized by 3 oxidation in order to remove the bivalent iron ion, and then the solution is oxidized in the form of oxide or hydroxide in a solid phase The iron can be removed by sludge formation and solid-liquid separation using means such as filtration.

Removal of iron ions from the re-leachate may be accomplished by oxidation of the iron ions to iron trivalent ions followed by formation of iron oxide and subsequent removal by solid-liquid separation. This can be expressed by the following equations (2) and (3). Specifically, as shown in Formula (2), an oxidation reaction is performed in which oxygen is blown into the re-leached solution to oxidize divalent iron ions to trivalent ions.

At this time, the reaction of formula (2) may not be sufficient with only air and oxygen, so that an oxidizing agent can be added to promote the oxidation reaction. Hydrogen peroxide can be used as the oxidizing agent. The hydrogen peroxide may be added in an amount of 10 to 100%, more preferably 15 to 30% of the oxygen equivalent ratio required for the oxidation of the divalent iron ions, whereby most of the divalent iron ions are converted into trivalent ions Can be oxidized.

After the iron ions are oxidized as described above, a solid iron oxide is formed by the hydrolysis reaction at a temperature of 100 ° C or higher, preferably 100 to 250 ° C, as shown in Formula (3), and sludge is formed. Therefore, a mixed solution containing nickel and cobalt can be obtained by filtering and removing solid iron oxide from the sludge.

On the other hand, the bivalent iron ions may be oxidized to trivalent ions, converted into iron hydroxide to form a solid phase, and then removed by solid-liquid separation. Specifically, iron hydroxide can be formed by carrying out an oxidation reaction for oxidizing divalent iron ions to trivalent iron ions by the same method as in the formula (2), and then introducing an alkali agent into the above-mentioned leaching solution, The leach solution becomes sludge. Therefore, a mixed solution containing nickel and cobalt can be obtained by filtering and removing solid iron hydroxide from the sludge.

At this time, the alkali agent is not particularly limited, but may include calcium hydroxide, caustic soda, hydroxides such as magnesium, iron and manganese. The alkaline agent is preferably added so that the pH of the re-leaching solution is 1.5 to 4.5. If it is added in a small amount outside the above range, the iron ion does not become iron hydroxide sufficiently, and when it is added in an excess amount, there is a problem such as nickel disappearance.

By removing iron ions from the re-leach solution by the above-mentioned method, a mixed solution containing nickel and cobalt can be obtained, whereby nickel and cobalt can be obtained in the form of a mixture. Further, nickel and cobalt can be obtained by separating and recovering nickel and cobalt by solvent extraction of the obtained mixed solution. At this time, the solvent extraction can be carried out using an organic solvent. For example, cobalt and nickel can be separated and recovered through solvent extraction, mixing, extraction, and stripping.

Example

Hereinafter, the present invention will be described more specifically by way of examples.

Example  One

- Pretreatment of nickel ore -

Containing remnants of oxygen and trace amounts of Mn and the like, containing 1.1% by weight of nickel, 1.1% by weight of Si, 1.1% by weight of Si and 2.5% by weight of Al, The kneaded ore was charged into a rotary kiln furnace maintained at 200 캜 and oxygen-free, treated for 3 hours, dried and pulverized by a roll mill to obtain a powder having an average particle size of 2 mm or less. The obtained powder was calcined at a calcination furnace at 600 캜 for 2 hours to prepare a nickel ore powder.

- Reduced light production -

The nickel ore powder was reduced with 1: 4 moles of hydrogen with respect to the number of moles of (Ni + Fe + Co) contained in the prepared nickel ore powder to produce 100 g of a reducing light.

The reduction temperature applied in the reduction step and the iron reduction ratio in the reduction light obtained by the reduction were measured and are shown in Table 1.

- Leaching reaction -

The thus-prepared reduced light was cooled in an oxygen-free tank filled with nitrogen gas, and 85 ml of water was added to 85 g of the reduced light to prepare a reduced optical slurry for leaching.

To the slurry thus prepared, a 20% strength hydrochloric acid solution was added to the slurry to prepare a 1 L solution. The solution was stirred to dissolve the reducing light and the leaching reaction was performed to leach nickel, iron and cobalt ions from the reducing light. The solid residue was filtered off from the leaching solution obtained by the leaching reaction to obtain a leaching solution.

- precipitation reaction -

In an anoxic tank filled with nitrogen gas, 15 g of the above-prepared reduced light was added to 15 ml of water and slurried to prepare a slurry for precipitation reduction. The thus-prepared reduced optical slurry for precipitation was charged into the obtained leaching solution to perform a displacement precipitation reaction of nickel and cobalt. The precipitation reaction was carried out under the temperature conditions shown in Table 1 for 2 hours.

The precipitate obtained by the precipitation reaction was separated from the precipitation filtrate, and the precipitate was recovered. The nickel concentration and the cobalt concentration in the recovered precipitate were analyzed to analyze the total nickel recovery and the cobalt recovery rate. The results are shown in Table 1.

Reduction reaction conditions Precipitation reaction condition Recovery rate (%) Temperature (℃) Iron reduction rate (%) Precipitation temperature (캜) nickel cobalt Comparative Example 1 630 ° C 65% 80 ℃ 75% 35% Inventory 1 730 ° C 75% 80 ℃ 90% 50% Inventory 2 830 ° C 84% 80 ℃ 95% 62% Inventory 3 930 ° C 84% 80 ℃ 95% 55% Comparative Example 2 730 ° C 75% 65 ℃ 65 25% Honorable 4 730 ° C 75% 95 ℃ 92% 53% Comparative Example 3 730 ° C 75% 105 ℃ 90% 50%

As shown in Table 1, in Comparative Example 1 in which the reduction temperature of nickel ore is low, the reduction rate is low and the precipitation reaction by iron is not sufficient, resulting in low nickel recovery and cobalt recovery.

On the other hand, when the reduction temperature is 925 캜 as in the case of Inventive Example 2, the reduction ratio, nickel and cobalt recovery are excellent values. However, it can be seen that the reduction rate is not increased any more, and that the recovery rate of cobalt is lower than that of Inventive Example 2, which is reduced at 830 ° C. This is because the sintering progresses as the reduction temperature increases and the activity tends to decrease. Therefore, it is preferable that the reduction temperature does not exceed 950 占 폚.

Further, as a result of changing the precipitation reaction temperature to improve the precipitation rate of cobalt, as can be seen from Comparative Example 3, the precipitation recovery rate was drastically decreased at a precipitation temperature of 70 ° C or lower. On the other hand, as can be seen from the comparative example 4, recovery of nickel and cobalt is ensured at a temperature of 100 ° C or higher, but the iron impurity is increased due to the hydrolysis reaction of iron to increase the weight of the precipitate and decrease the quality of nickel and cobalt Resulting in undesirable results.

Example  2

- Separation of ferronickel metal and recovery of cobalt -

Water was added to the precipitate in which nickel and cobalt were precipitated from the inventive example 1 at a weight ratio of 1: 1 based on the weight of the precipitate, and hydrochloric acid was added at a concentration of 20% to re-leach nickel and cobalt. At this time, hydrochloric acid was added so as to be 2.5 times the number of moles of (Fe + Ni + Co) in the precipitate. The leachate was analyzed and it was confirmed that nickel, cobalt and iron ions were leached similarly to the composition ratio of ore.

Oxidation reaction was performed by blowing oxygen into the re-leached re-leach solution. At this time, hydrogen peroxide was added together with 20% of the oxygen equivalent ratio required for the oxidation.

Subsequently, the re-leachate was heated to a temperature of 120 ° C to hydrolyze it, and it was confirmed that solid iron oxide was generated in the re-leachate.

The solid iron oxide was removed from the re-leach solution by filtration to obtain a mixed solution containing nickel and cobalt.

Further, Co ion was recovered from the mixed solution with an organic solvent (Aliquat), and nickel was extracted and recovered using an organic solvent Versatic-10.

Claims (14)

A reducing step of reducing the ore containing Ni, Co and Fe to a hydrogen-containing gas to obtain reduced light for leaching;
A leaching step of dissolving the reduced light in an acid to leach out Ni, Co, and Fe ions, and removing solid matter by solid-liquid separation to obtain an leached solution containing Ni, Co, and Fe ions;
The precipitation reduction light obtained by reducing the ores containing Ni, Co and Fe into a hydrogen containing gas is introduced into the above-mentioned leaching solution to replace nickel and cobalt in the leaching solution with iron in the above-mentioned precipitation reduction light to obtain a precipitate in which Ni and Co are precipitated Precipitation step;
A re-leaching step of dissolving the precipitate in an acid to re-leach nickel and cobalt to obtain a re-leach solution;
A sludge forming step of oxidizing dihydric iron ions in the re-leach solution to trivalent iron ions, forming a solid iron compound of iron oxide or iron hydroxide to sludge; And
The solid component is removed by solid-liquid separation to remove the iron and Ni and Co-containing solution containing Ni and Co
≪ / RTI >
The method for recovering nickel and cobalt according to claim 1, wherein the reducing light for leaching and the reducing light for precipitation are reduced at a temperature of 725-950 캜.
The method for recovering nickel and cobalt according to claim 1, wherein the precipitation-reduced light has an iron reduction rate of 75-95%.
The method of claim 1, wherein the acid in the leaching step and the leaching step are each independently sulfuric acid or hydrochloric acid.
The method of claim 1, wherein the precipitation step is performed at 70-100 < 0 > C.
The method of claim 1, wherein the oxidation is performed by injecting an oxygen-containing gas into the re-leaching solution to oxidize the ferric ions to the ferric ions.
7. The method of claim 6, wherein the oxidation further oxidizes the oxidant in the re-leach solution together with the oxygen-containing gas to oxidize the nickel and cobalt.
8. The method of claim 7, wherein the oxidant is hydrogen peroxide.
The method of claim 8, wherein the hydrogen peroxide is fed at 10-30% of the oxygen equivalent ratio required for the oxidation of the divalent iron ions.
The method for recovering nickel and cobalt according to claim 1, wherein the iron oxide is iron oxides formed by thermally hydrolyzing the re-leaching solution containing the trivalent iron ions at a temperature of 100 to 250 ° C.
The method of claim 1, wherein the iron hydroxide is produced by introducing an alkaline agent into the re-leaching solution comprising the trivalent iron ion.
12. The method of claim 11, wherein the alkaline agent is introduced such that the pH of the re-leach solution is between 1.5 and 4.5.
The method of claim 12, wherein the alkaline agent is a hydroxide of calcium, sodium, magnesium, iron, nickel or manganese or a mixture of two or more thereof.
14. The nickel and cobalt recovery method according to any one of claims 1 to 13, further comprising separating and recovering nickel and cobalt by solvent extraction of the nickel and cobalt-containing solution.