KR20160077399A - Method for Producing Ferro Nickel - Google Patents

Abstract

The present invention is to provide a method for manufacturing a ferro nickel of high quality, by utilizing an iron chloride roasted iron ore obtained from a byproduct of a nickel smelting process as a seed raw material for precipitation. According to an embodiment of the present invention, provided is the method for manufacturing the ferro nickel, which includes the steps of: obtaining a reduced raw material containing nickel iron by deoxidizing a raw material containing nickel iron; preparing a roasted iron ore for precipitation by indirectly reducing the iron chloride roasted iron ore obtained from the byproduct of the nickel smelting process; manufacturing slurry of the reduced raw material containing nickel iron by slurrying the reduced raw material containing nickel iron; obtaining a solution containing nickel iron ion by inserting an acid to the slurry of the reduced raw material containing nickel iron for precipitation; precipitating the ferro nickel by inserting the roasted iron ore for precipitation of 5-15 wt% as to total weight of the reduced raw material containing nickel iron for precipitation into the solution containing nickel iron ion; separating ferro nickel case from the solution after precipitation; and obtaining the ferro nickel by roasting and reducing the separated ferro nickel case directly. According to one aspect of the present invention, the method can manufacture the ferro nickel of high quality more economically and eco-friendly.

Description

Method for Producing Ferro Nickel [0002]

The present invention relates to a method for producing ferronickel from nickel iron-containing raw materials, and more particularly, to a method for producing high-quality ferronickel utilizing iron chloride-roasting iron obtained from a by-product of a nickel smelting process.

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.

Accordingly, 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, and this 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.

However, it is known that HPAL method should be carried out under high temperature and high pressure of autoclave, and it is known that it is mainly used for the titanium material because of its strong acidity, and accordingly, the equipment cost is very high and the maintenance cost is high.

In addition, caustic soda, which is an expensive precipitation agent, is used for nickel concentration or an environmentally hazardous precipitant such as H ₂ S is used.

In addition, when leaching the limonite nickel ore by applying the above method, high-speed leaching was possible, but the limonite ore has a high iron content and a low nickel content, and when the nickel is leached by acid dissolution, On the other hand, a small amount of nickel is leached, which makes it difficult to separate iron and nickel from the leached product.

A technique for improving the above-mentioned problem is disclosed in Korean Patent No. 1353721.

The patent document discloses a method capable of effectively concentrating nickel and recovering ferronickel from such a concentrate by separating and recovering nickel and iron from ores having a low nickel grade.

However, in the case of the above method, a large amount of impurities such as Mg and Si are contained in the reducing raw material for precipitation, in addition to nickel and iron, and there is a problem that many by-products such as slag are generated when ferronickel is recovered after precipitation.

Korean Patent Publication No. 2007-7020915 Japanese Laid-Open Patent Publication No. 2010-031341 Korean Registered Patent No. 1353721

An aspect of the present invention is to provide a method for producing high-quality ferronickel by utilizing iron chloride-roasting iron ore obtained from a by-product of a nickel smelting process as a raw material for seeding for precipitation.

One aspect of the present invention is

Reducing the nickel-iron-containing raw material with a reducing gas containing hydrogen to obtain a nickel-iron-containing reducing raw material;

Indirectly reducing iron chloride iron ore obtained from a by-product of a nickel smelting process with solid carbon or a reducing gas to prepare a roasted iron ore for precipitation;

Slurrying the nickel iron-containing reducing raw material to prepare a slurry of nickel iron-containing reducing raw material for leaching;

Adding an acid to the slurry of nickel iron-containing reducing raw material for leaching to dissolve and leach nickel and iron with ions, and then removing the residue to obtain a solution containing nickel iron ion;

5 to 15% by weight of the precipitating roasting iron ore for the nickel iron-containing reducing raw material for leaching is charged into the nickel iron ion-containing solution so that the iron component of the precipitating roasting iron ore is contained in the nickel iron ion- Nickel so as to precipitate ferronickel;

Separating the ferronickel cake and the solution after the precipitation; And

And roasting and directly reducing the separated ferronickel cake to obtain ferronickel.

When the iron chloride-roasting iron ore is reduced with a reducing gas, the reduction temperature may preferably be 550 to 900 ° C.

In the case of reducing the iron chloride-calcined iron ore to solid carbon, the reduction temperature may preferably be 700 to 1200 ° C.

The calcining rosin for precipitation preferably contains Fe, Ni, Mg, Si, and Al in an amount of 5 wt% or less.

The nickel content of the ferronickel cake may be 4.5 wt% or more, for example, 4.5 to 33 wt%.

The iron chloride-roasting iron ore may be obtained by the following steps: obtaining a concentrated solution by evaporating and concentrating the iron ion and chloride ion-containing solution generated in the filtrate in the nickel smelting process; Crystallizing the concentrated solution to obtain iron chloride crystals; Solid-liquid separation of the iron chloride crystals and the slurry; And roasting the iron chloride crystals to obtain iron chloride-roasting iron ores.

According to one aspect of the present invention, it is possible to provide a high-quality ferronickel, and furthermore, it is possible to reduce the cost due to no need of the melting and reducing process as in the prior art, And by utilizing the iron chloride-roasting iron ore obtained as a by-product of the nickel smelting process, it can bring about an environmentally-friendly and economical effect.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for producing ferronickel from a raw material containing nickel and iron, and particularly relates to a method for producing ferronickel from a raw material containing nickel and iron, in which nickel is reduced and iron concentration is high in recovering nickel by acid dissolution, , Whereas nickel can be more suitably applied in cases where it is difficult to separate iron and nickel due to leaching of a small amount of nickel.

The nickel-iron-containing raw material to which the present invention can be applied is not particularly limited, and any nickel or iron-containing raw material may be used as long as it contains nickel and iron, and preferably nickel ores such as limonite, .

Nickel ore has a content of Ni 1-2.5% and Fe 15-55%, though the amount varies depending on the type of ore. In the case of limonite ores, the nickel concentration is as low as 1-1.8% and the iron concentration is 30-55 %. The present invention can also be effectively applied to recovering nickel from such a relatively low nickel content limbite.

Pretreatment of nickel iron-containing raw materials

In recovering nickel from the nickel-iron-containing raw material, a pretreatment step may be carried out if necessary in order to effectively reduce the nickel-iron-containing raw material in the reduction step. Such pretreatment processes include drying, grinding and calcining steps.

The nickel-iron-containing raw material, which is the 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-containing ore is previously pulverized and applied to the nickel recovery process.

The nickel-iron-containing raw material usually contains about 30 to 40% of the number of the attached water and about 10% of the water of the crystalline water. When pulverized in the state containing such water, the pulverization efficiency is lowered, When the raw material is crushed after sintering, there is a fear that the crushing equipment is burdened due to high temperature. Therefore, it is preferable to dry the nickel iron-containing raw material before pulverizing the nickel iron-containing raw material 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 iron-containing raw material is pulverized after being 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 crystal water contained in the nickel-iron-containing raw material is not removed in the above-mentioned drying process. In such a crystal water, the crystal water contained in the ore is released as moisture in the reduction process of the nickel iron-containing raw material, and this water slows 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 iron-containing raw material.

Among the nickel-iron-containing raw materials, 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 the case of the nickel-iron-containing raw material. However, in the case where the dust is exposed to air and contains moisture, it may be subjected to grinding or firing as necessary.

Step of obtaining nickel iron-containing reducing raw material

In the present invention, nickel iron-containing raw materials are reduced to obtain nickel iron-containing reducing raw materials.

The reduction of the nickel-iron-containing raw material can be performed in a temperature range of 550-950 DEG C using a reducing gas containing hydrogen as a reducing agent. When the reduction temperature is less than 550 ° C., the reduction does not occur sufficiently, so that the recovery rate upon leaching into the acid solution in the subsequent step may be low and the precipitation yield may also be lowered.

On the other hand, the higher the reducing temperature, the higher the leachate yield and precipitation yield. However, in the case of reduction at a temperature exceeding 950 占 폚, there is no problem in reducing the nickel-iron-containing raw material, however, no further reduction in the reduction efficiency can be obtained and, rather, intergranular sintering may occur, The specific surface area is reduced to 1 m < 2 > / g or less, which may result in a decrease in precipitation yield. Therefore, it is preferable to perform the reduction process in the temperature range as described above.

As the reducing gas, a gas containing hydrogen may be used. In the case of gas reduction using CO gas 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, There is a problem that the leaching rate is rapidly lowered due to the low activity, and in particular, the precipitation efficiency in the precipitation step is remarkably lowered.

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 CO 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.

In the raw materials used in the reduction process, the ratio of nickel to iron differs depending on the raw material used. For example, in the case of limonite ores, nickel and iron are usually contained at a weight ratio of 1:30. That is, the nickel content in the limonite ores is approximately 1-1.5% by weight, and the iron content is approximately 30-45% by weight. When such a limonite ore (nickel: iron = 1: 29) is reduced using hydrogen as a reducing gas, a reducing raw material is obtained by a theoretical reduction reaction as shown in the following formula (1).

_{(Ni 0 .1 Fe 0 .9)} OFe 2 O 3 + 4H 2 = (Ni 0 .1 Fe 0 .9) + 2Fe + 4H 2 O (1)

Hydrogen used as a greenhouse gas in such a reduction reaction reacts with oxygen of nickel and iron present in an oxidized state in the nickel-iron-containing starting material to produce water, thereby reducing the nickel and iron. Therefore, the amount of hydrogen contained in the reducing gas may be included in an amount equal to or greater than the theoretical equivalence ratio, and hydrogen may be added in excess of the theoretical equivalence ratio for efficient reduction reaction. However, such a hydrogen is expensive, and the higher the equivalent ratio of hydrogen to the hydrogen is, the higher the cost of the process is, and it is not preferable to use the hydrogen excessively, and hydrogen can be supplied in an appropriate amount. For example, the amount of hydrogen introduced may be included in the molar amount of, for example, 1 to 5 times, 2 to 5 times, or 2 to 4 times the theoretical equivalent ratio.

The nickel iron-containing raw material reduced by this reaction can be obtained. The reduced nickel iron-containing raw material is hereinafter also referred to as a " reducing raw material ".

Precipitation Roasting iron ore  Steps to prepare

In the present invention, iron chloride iron ore obtained from a by-product of a nickel smelting process is indirectly reduced with solid carbon or a reducing gas to prepare a roasted iron ore for precipitation.

When the iron chloride-roasting iron ore is reduced using a reducing gas with a reducing agent, the reducing temperature is preferably 550 to 900 ° C. When the reduction temperature is less than 550 ° C, there is a problem that the reduction time is long due to the kinetics problem that the roasting iron ore is reduced to Fe from Fe ₃ O ₄ without passing through the reducing intermediate FeO. In case of 900 ° C or more, The Fe reduced to the temperature is sintered or the energy is excessive, which is problematic from the viewpoint of economical efficiency.

When the iron chloride-roasting iron ore is reduced using solid carbon with a reducing agent, the reduction temperature is preferably 700 to 1200 ° C. When the reduction temperature is less than 700 ° C, there is a problem that the reduction rate takes a long time. When the reduction temperature is 1200 ° C or more, the reduced Fe sinter or the energy is excessively large,

As the reducing gas, hydrogen, CO, a mixed gas thereof, or a gas containing at least one of hydrogen and CO may be used.

For example, the reducing gas may be 100% hydrogen or 100% CO or a mixture gas of hydrogen and CO or hydrogen + CO + LNG reforming gas or COG.

As the solid carbon, coal, coke, or the like can be used.

The precipitation-roasted iron ore may contain 5 wt% or less of elements such as Fe, Ni, Mg, Si and Al, and preferably 3 wt% or less.

The precipitation-rosemary iron ore for precipitation is, for example, 58 to 72 wt% of Fe, 1 wt% or less of Ni, 5 wt% or less, preferably 3 wt% or less of Mg, And other impurities.

The iron chloride roasting iron ore used in the present invention can be obtained from ferric ion and chloride ion-containing solution generated in the filtrate in a nickel smelting process for recovering nickel from a nickel ore containing nickel and iron using a hydrochloric acid solution.

One example of the iron chloride-roasting iron ore used in the present invention is a iron ore-containing iron ore containing iron and chlorine ions generated in a filtrate in a nickel smelting process in which nickel is recovered from a nickel ore containing nickel and iron using a hydrochloric acid solution Evaporating the solution to obtain a concentrated solution; Crystallizing the concentrated solution to obtain iron chloride crystals; Solid-liquid separation of the iron chloride crystals and the slurry; And roasting the iron chloride crystals to obtain iron chloride-roasting iron ores.

The evaporation and crystallization of the iron ion and chloride ion-containing solution are preferably carried out at a temperature of from 0.1 to 1 atm, and at a temperature of from 50 to 110 ° C.

When the pressure of the iron ion and the chloride ion-containing solution is evaporated and crystallized, when the pressure is less than 0.1 atmospheric pressure, the energy cost may be increased in relation to the maintenance of high vacuum. In the case of exceeding 1 atm, Of the total number of users.

On the other hand, when the evaporation and the crystallization are carried out at a temperature lower than 50 캜, evaporation is not carried out at normal pressure, and in the case of reduced pressure, high vacuum degree can be maintained and energy cost can be increased. Which can lead to an increase in energy costs.

The roasting of the iron chloride crystals is preferably carried out at a temperature of 400 to 1000 ° C.

When the roasting temperature of the iron chloride crystals is less than 400 ° C, there is a fear that the pyrolysis of the iron chloride crystals does not occur well, and if it exceeds 1000 ° C, the energy cost may increase. It is more preferable to set the roasting temperature of the iron chloride crystals at 600 to 800 DEG C from the viewpoint of economical efficiency such as energy consumption required for roasting.

On the other hand, an example of the iron ion and chloride ion-containing solution generated in the filtrate in the nickel smelting process is as follows:

A leaching step of dissolving nickel ore containing Ni and Fe with hydrochloric acid to obtain an leached solution containing Ni and Fe ions; Adjusting pH by adding an alkaline agent to the leaching solution, removing the solid impurities from the leaching solution by solid-liquid separation, Adding nickel ore containing Ni and Fe to the leach solution, and precipitating nickel into ferronickel; And a precipitate recovery step of separating the solid precipitate from the precipitation liquid to recover and recover solid precipitate, and a filtrate generated in the nickel smelting step.

The content of the alkaline agent added to the leach solution is not particularly limited, but it is preferable that the alkaline agent is added so that the pH of the leach solution is 1.5 to 3.5. The pH of the leached filtrate obtained by the addition of the acid during the leaching reaction has a very high acidity, usually 1 or less. By adjusting the pH to the above range, the Al, Si and Cr components present in the solution can be effectively removed. However, when the pH of the precipitation filtrate exceeds 3.5, the iron ions in the solution are also converted into hydroxides, which may result in lowered iron recovery. It is more preferable that the pH does not exceed 3.5.

At this time, the alkaline agent to be added for controlling the pH of the above-mentioned leaching solution is not particularly limited and can be used without limitation as long as it can raise the pH of the leaching solution. For example, the alkali agent may be a metal hydroxide selected from the group consisting of Mg, Fe, Ni, Mn, Na, K, and Ca, or a mixture of the metal hydroxide.

Further, another example of the iron ion and chloride ion-containing solution generated in the filtrate in the nickel smelting process is the following process:

Reducing the nickel-iron-containing raw material powder with a reducing gas containing hydrogen to obtain a reducing raw material, and slurrying the reducing raw material in an inert atmosphere to produce a slurry of the reducing raw material for leaching;

Adding hydrochloric acid to the slurry of the reducing raw material for leaching to dissolve and leach nickel and iron into ions, and then removing the residue to obtain a solution containing nickel iron ion;

Introducing a reducing raw material for precipitation obtained by reducing the nickel and iron containing raw material into the nickel iron ion containing solution to replace the iron of the precipitation reducing raw material with nickel in the nickel iron ion containing solution to precipitate ferronickel; And a step of solid-liquid separation of the solid content including ferronickel.

Of reduced nickel iron-containing raw material The slurry  Steps to manufacture

In the present invention, the reduced nickel iron-containing raw material, that is, the reducing raw material is slurried by 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 raw material from being reoxidized by oxygen.

Since the reducing raw material obtained by reducing the nickel iron-containing raw material has high activity and the content of the iron component is very high, when the reducing raw material is extracted into the air after reduction, reductant of the reducing raw material is reoxidized, Is accelerated to have a risk of fire. Therefore, oxidation and ignition of the reducing raw material can be prevented by slurrying the reducing raw material with water.

Water may be administered to bring the slurry concentration to 1-2 times the weight of the reducing raw material. If the water content is out of the above range and the water is too small, the concentration of the slurry may be high, which may cause transfer problems. If the water is excessively administered, the concentration of the solution after dilution becomes undesirably low.

Step of obtaining nickel iron ion-containing solution

In the present invention, the reducing raw material is slurried, and then acid is added to the slurry to dissolve and dissolve ferronickel of nickel iron contained in the reducing raw material in the slurry to ionize nickel to nickel ion and iron to iron ion.

The acid leaching step may dissolve the reducing raw material by adding an acid to the slurried reducing raw material in an anaerobic reactor and agitating it. As described above, when the slurry is formed, oxidation of the reducing raw material is not likely to occur. However, if the raw material is strongly stirred in an oxygen atmosphere, for example, in the atmosphere, the reducing raw material in the slurry may be oxidized by a kind of hydration reaction. Thus, the acid leaching step is preferably carried out in an oxygen-free state.

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

Generally, when the reducing raw material reduced by the reduction reaction of the formula (1) is leached into an acid, the ferronickel in the reducing raw material is dissolved by the acid as the reaction of the following formulas (2) and (3) Leached.

_{(Ni 0 .1 Fe 0 .9)} + 2Fe + 6HCl = (Ni 0 .1 Fe 0 .9) Cl 2 + 2FeCl 2 + 3H 2 (2)

_{(Ni 0 .1 Fe 0 .9)} + 2Fe + 3H 2 SO 4 = (Ni 0 .1 Fe 0 .9) SO 4 + 2FeSO ₄ + 3H ₂ (3)

When hydrochloric acid is used as an acid in order to leach such a reducing raw material into an acid, hydrochloric acid should be added at a molar number twice or more the number of moles of (Fe + Ni), as can be seen from the above formula (2). However, when hydrochloric acid is added in a quantity exceeding 4 times the number of moles of (Fe + Ni), further improvement in leaching efficiency can not be obtained, and it is preferable that the molar amount is 2 to 4 times the number of moles of (Fe + Ni) Do. On the other hand, in the case of using sulfuric acid as an acid, 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) of the nickel iron containing raw material, as can be seen from the above formula (3).

Such an acid leaching reaction is an exothermic reaction accompanied by a temperature rise in the reactor. Therefore, an acid leaching reaction can be performed even at room temperature, and when the acid leaching reaction is carried out at a temperature of 20 캜 or higher, a good leaching efficiency can be obtained. Furthermore, such an acid leaching reaction can be carried out by heating in an appropriate range, and when it is carried out by heating, the leaching rate can be improved and the leaching time can be shortened. The temperature during the heating may be suitably set according to the condition 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 acid dissolution reaction, the ORP is negative, and when the metal is completely dissolved in the acid, the ORP is changed to zero after the ORP is zero. Therefore, when the ORP is 0 or more, the acid dissociation reaction can be stopped, and the end point of the acid dissociation 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-iron-containing raw material hardly dissolve by the acid, and are obtained as solid phase residues. Therefore, the iron and nickel ion-containing solution and the solid residue obtained by the leaching step can be easily separated by filtration and can be separated by a solid-liquid separator such as a filter press or a decanter to obtain iron and nickel ion-containing solutions .

Ferronickel Precipitate  step

Next, the iron and nickel ions dissolved in the reaction of the above formula (2) or (3) are precipitated in ferronickel.

In the present invention, at the time of precipitation of ferronickel, the roasting iron ore for precipitation which is indirectly reduced by the solid carbon or the reducing gas as described above is used as the seed material for precipitation.

At this time, the input amount of the roasted iron ore for precipitation depends on the And 5 to 15% by weight based on the total weight.

In this case, when the amount of iron ore for deposition is less than 5%, the amount of nickel remaining in the solution after leaching is large and the recovery rate is low due to precipitation, and when the amount exceeds 15% This is because the concentration of recovered nickel is low.

When the precipitation-roughening iron ore is charged into the iron and nickel ion-containing solution, the nickel of the iron and nickel ions dissolved by the reaction represented by the following formula (4) or (5) And is substituted with metal.

_{(FeCl 2 + NiCl 2) +} 2Fe = FeNi + 2FeCl 2 (4)

_{(FeSO 4 + NiSO 4) +} 2Fe = FeNi + 2FeSO 4 (5)

The principle of the substitution reaction such as the above formula is due to the natural potential difference between iron and nickel, and is caused by a cell reaction as shown in the following reaction formula.

Anode ^{reaction: Fe = Fe 2 + + 2e} E 0 = 0.44Fe = Fe 2 + + 2e E 0 = 0.44

Cathode ^{reaction: Ni 2 + + 2e = Ni} E 0 = - 0.25Ni 2 + + 2e = Ni E 0 = - 0.25

Total reaction: Fe + Ni ^{2 + 2} = Fe ⁺ Ni = E ⁰ 0.19Fe + Ni ^{2 + 2} = Fe ⁺ Ni = E ⁰ 0.19

That is, a cell is formed by a natural potential difference between nickel and iron in iron and nickel ion-containing solution, and the dissolution reaction by the oxidation of iron proceeds in the anode site, and the iron and nickel ion The reaction in which nickel ions in the solution are reduced and precipitated proceeds.

Since the solubility of iron in the aqueous solution is about 150 g / l, the soluble concentration of nickel at the time of acid leaching is limited to 5 g / l or less. Therefore, the concentration of nickel in the solution obtained by the leaching reaction of the above formulas (2) and (3) is usually between 2 and 5 g / l. As described above, since the nickel concentration is small, the substitutional precipitation reactions such as the above-mentioned formulas (4) and (5) do not usually occur. That is, when a small amount of atomized iron powder is added to a solution having a low nickel concentration, a very low precipitation recovery rate of nickel is obtained. In addition, when the above general iron powder is administered at a quantity of 20 times or more of the nickel content, the precipitation recovery rate of nickel can be somewhat improved, but the nickel concentration in the obtained precipitate is not high, which is not economical.

However, when the roasting iron ore for precipitation is charged into the iron and nickel ion-containing solution, nickel can be effectively deposited and recovered even when a small amount is added.

Since the precipitation annealing iron ore has a very high activity, efficient precipitation of nickel can be achieved. The amount of the roasted iron ore to be deposited into the iron and nickel ion-containing solution for the reduction of nickel can be controlled according to the amount of the reducing raw material for leaching, and the use ratio of the roasted iron ore is determined by the precipitation recovery rate of nickel, It is very important as a factor in determining the nickel concentration of the product.

Ferronickel  cake( cake ) And separating the solution

After the ferronickel is precipitated from the nickel ion-containing solution as described above, the ferronickel cake and the solution are separated.

The solid component containing ferronickel is separated from the solution by filtration to remove the iron ion-containing solution to obtain a ferronickel cake, which is a nickel concentrate having increased nickel concentration.

The nickel content of the ferronickel cake may be 4.5 wt% or more, for example, 4.5 to 33 wt%.

The ferronickel cake may contain Mg, Si, Al and Cr in a total amount of 10 wt% or less, preferably 5 wt% or less.

As described above, if the nickel concentration of the ferronickel cake is 4.5 wt% or more, it is possible to make the raw material in the form of ferronickel.

Particularly, when the nickel concentration of the ferronickel cake is 4.5 wt% or more and Mg, Si, Al, Cr or the like is contained by 10 wt% or less, high purity ferronickel can be obtained by roasting and direct reduction.

Ferronickel  Steps to Obtain

After the ferronickel is precipitated and the concentrated product (ferronickel cake) is filtered, the ferronickel cake is roasted and directly reduced to obtain ferronickel.

The ferronickel precipitates and concentrates the product (ferronickel cake) after filtration, for example, by agglomeration by pelletizing or briquetting, roasting in a rotary hearth furnace (RHF) or a rotary kiln, Ferronickel can be obtained.

The roasting and direct reduction can be carried out using, for example, solid carbon or a reducing gas. Examples of the solid carbon include coal, coke or a mixture thereof. As the reducing gas, hydrogen, CO, Gas.

The roasting temperature may be, for example, 600 to 850 캜.

The reduction temperature during the direct reduction may be 550 to 1250 ° C.

In the present invention, the product (ferronickel cake) in which ferronickel is precipitated and precipitated as described above is agglomerated by pelletizing or briquetting, roasted and directly reduced in a rotary hearth furnace (RHF) or a rotary kiln to obtain high purity ferronickel It is possible to reduce the cost due to no need for the melting and reducing step of the prior art, and also to prevent the slag, which is a waste generated from the melting and reducing step, from being generated.

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

(Example)

Pretreatment of raw materials

The limonite ores having the composition shown in the following Table 1 were dried in a rotary kiln at 150 ° C for 30 minutes and then pulverized using a super mill to prepare powders having an average particle size of about 15 μm.

The obtained powder was fired in a firing furnace maintained at 700 to 800 ° C for 1 hour to remove crystal water from the ore powder.

Production and Reduction of Reduced Raw Material Slurry  Produce

The calcined nickel light was discharged from the calcination furnace and charged into a rotary kiln reduction furnace where oxygen was shut off. Then, hydrogen at a molar ratio of 4 times the number of moles of (Ni + Fe) contained in the prepared ore powder was used, To produce a reduced light.

The components of the reduced light obtained by such reduction are analyzed and shown in Table 1 below.

In Table 1, the content of each component represents weight%, and the balance is oxygen and trace amounts of Cr, Mn, Co and the like.

Ni Fe Mg Si Al Dry light 1.33 44.2 1.7 3.9 2.4 Reduction light 1.85 61.6 2.4 5.4 3.3

The thus-prepared reduced light was cooled in an anoxic tank filled with nitrogen gas, and 150 ml of water was added to 150 g of the reduced light to prepare a slurry.

Precipitation  Roasting iron ore preparation

The ferrous and chlorine ion-containing solutions, which are byproducts of the nickel smelting process, are evaporated and crystallized at a temperature of 80 ° C. and 1 atm to obtain iron chloride crystals. Solid iron chloride crystals are then roasted at a temperature of 800 ° C., Were prepared.

The composition of the iron chloride-iron ore is shown in Table 2 below.

Iron chloride iron ores having the composition shown in Table 2 below were indirectly reduced under the conditions shown in Table 3 to prepare iron ores for precipitation.

The composition of the roasted iron ore for precipitation prepared as described above is shown in Table 4 below,

Table 4 also shows the composition of the conventional reduced light for precipitation.

In the following Tables 2 and 4, the content of each component represents weight%, and the balance is oxygen and trace amounts of Cu, Zn and the like.

Mg Ca Mn Fe Co Ni Cr Si Al Roasted iron ore 0.35 0.53 0.49 58.2 0.083 0.25 0.068 0.25 0.17

Type of reducing agent Reduction temperature (캜) Reduction time Iron ore for precipitation Hydrogen gas 850 degrees 30 minutes

Precipitation seed type Mg Ca Mn Fe Co Ni Cr Si Al Iron ore for precipitation 0.46 0.66 0.66 77.9 0.10 0.33 0.088 0.26 0.20 Precipitation reduction light 2.35 0.13 1.00 61.6 0.29 1.85 3.03 5.41 3.33

Leaching process

To the slurry of the reducing raw material thus prepared, 20% strength hydrochloric acid was added to the slurry to prepare 1 liter of a solution and stirred to perform an acid leaching reaction in which ferronickel ions were leached from the reduced light.

ICP ( inductively coupled Plasma emission spectrometry was used to investigate the nickel concentration of the leach solution obtained by the acid leaching reaction using the slurry at room temperature. As a result of the investigation, it was confirmed that the nickel concentration in the leachate was 4.04 g / l, and the recovery rate of nickel leaching (nickel weight in the leach solution / nickel weight in the ore) was found to be about 94%.

The solid residue was removed by solid-liquid separation from the leaching solution obtained by the leaching reaction.

Precipitation  And separation process

In order to precipitate ferronickel from the obtained leach solution, the deposition iron precipitation for precipitation and the precipitation reduction light prepared as described above were introduced into the leaching solution to perform the substitution precipitation reaction of ferronickel. The amounts of the above-described roasted iron ores for precipitation and the amounts of the precipitated reduced light are shown in Table 5 below.

The components in the solution were subjected to ICP emission spectrometry to calculate the nickel precipitation recovery rate by the following equation, and the results are shown in Table 5.

Nickel recovery (%) = {(nickel concentration in leaching solution - nickel concentration in solution after precipitation) / (nickel concentration in leaching solution)} X 100

Example No. 2. Precipitation seed type Input amount (% by weight) Recovery rate Honor Iron ore for precipitation Reduced light intensity for leaching 10% 91.3% Comparative Example Precipitation reduction light Reduced light intensity for leaching 14% 93.7%

After the substitutional precipitation reaction was performed for 2 hours, the feronickel cake and the solution were separated, and the components in the ferronickel cake and the solution (filtrate) were examined. The results are shown in Tables 6 and 7 Respectively.

In Table 6, the content of each component represents weight%, and the content of each component in ppm represents ppm. In Table 6, the remainder is water, chlorine, and other impurities, and the remainder in Table 7 is chlorine and other impurities.

Mg Ca Mn Fe Co Ni Cr Si Al Honor 0.28 0.43 0.28 52.6 0.39 11.35 0.061 0.16 0.15 Comparative Example 2.5 0.1 0.7 36.1 0.2 7.6 2.5 6.6 3.6

Mg Ca Mn Fe Co Ni Cr Si Honor 3831 7840 2017 140300 257 390 <10 30 Comparative Example 3872 223 1471 160831 410 187 <10 35

Ferronickel  Produce

The ferronickel cake produced according to the present invention as described above was agglomerated, roasted and directly burned, and then cooled to prepare ferronickel.

At this time, the roasting temperature was 800 ° C, the direct reduction temperature was 1150 ° C, and the solid carbon was used as the reducing agent.

On the other hand, the ferronickel cake produced according to the comparative example was agglomerated, roasted in an electric furnace, slag separated, and cooled to prepare ferronickel.

The coal used was 51.5% of fixed carbon and the calorific value was 6100 kcal / kg.

As described above, the waste amount (kg), the amount (kg) to be used and the required amount of energy (Mcal) generated in the production of 1 tonne of ferronickel during the production of ferronickel were investigated.

Example No. 2. FeNi recovery method FeNi and other waste Coal consumption Required Energy Honor Precipitation Cake Direct Reduction Including FeNi and other 99kg impurities 644kg 507 Mcal Comparative Example Precipitation cake melting Slag 548kg 657kg 1511 Mcal

As shown in Tables 5, 6, and 8, when the roasting iron ore for precipitation as the precipitation seed is used according to the present invention, the amount of impurities such as Mg and Si is significantly smaller than that of the conventional reduction- It is possible to manufacture a high-quality ferronickel without the need of a process and without the generation of slag, which is a waste generated from the melting and reducing process. In particular, in the present invention, it is possible to obtain an environmentally-friendly and economical effect by utilizing the iron chloride-roasting iron ore obtained as a by-product of the nickel smelting process.

Claims (14)

Reducing the nickel-iron-containing raw material with a reducing gas containing hydrogen to obtain a nickel-iron-containing reducing raw material;
Indirectly reducing iron chloride iron ore obtained from a by-product of a nickel smelting process with solid carbon or a reducing gas to prepare a roasted iron ore for precipitation;
Slurrying the nickel iron-containing reducing raw material to prepare a slurry of nickel iron-containing reducing raw material for leaching;
Adding an acid to the slurry of nickel iron-containing reducing raw material for leaching to dissolve and leach nickel and iron with ions, and then removing the residue to obtain a solution containing nickel iron ion;
5 to 15% by weight of the precipitating roasting iron ore for the nickel iron-containing reducing raw material for leaching is charged into the nickel iron ion-containing solution so that the iron component of the precipitating roasting iron ore is contained in the nickel iron ion- Nickel so as to precipitate ferronickel;
Separating the ferronickel cake and the solution after the precipitation; And
And roasting and directly reducing the separated ferronickel cake to obtain ferronickel.
The method according to claim 1,
Wherein the acid added to the slurry is hydrochloric acid or sulfuric acid.
The method according to claim 1,
Wherein the reduction temperature is 550 to 900 DEG C when the iron chloride-roasting iron ore is reduced with a reducing gas.
The method according to claim 1,
Wherein when the iron chloride-roasting iron ore is reduced with solid carbon, the reduction temperature is 700 to 1200 ° C.
The method according to claim 1,
Wherein the roasting temperature of the ferronickel cake is 600 to 850 ° C.
The method according to claim 1,
Wherein the direct reduction temperature of the ferronickel cake is 550 to 1250 ° C.
The method according to claim 1,
Wherein the precipitation-roughening iron ore for smelting contains Mg, Si and Al in a total amount of 5 wt% or less.
The method according to claim 1,
Wherein the calcining roasted iron ore for the precipitation comprises 58 to 72 wt% of Fe, 1 wt% or less of Ni, 5 wt% or less of Mg, Si and Al, and oxygen and other impurities. &Lt; / RTI &gt;
The method according to claim 1,
Wherein the ferronickel cake has a nickel content of 4.5 wt% or more.
10. The method of claim 1 or 9,
Wherein the ferronickel cake contains Mg, Si, Al and Cr in a total amount of 10 wt% or less.
The method according to claim 1,
The iron chloride-roasting iron ore
Evaporating and concentrating the iron ion and chlorine ion-containing solution generated in the filtrate in the nickel smelting process to obtain a concentrated solution;
Crystallizing the concentrated solution to obtain iron chloride crystals;
Solid-liquid separation of the iron chloride crystals and the slurry; And
And a step of roasting the iron chloride crystals to obtain iron chloride-roasting iron ores.
12. The method of claim 11,
Wherein the evaporation and crystallization of the iron ion and chloride ion-containing solution is carried out at a temperature of from 0.1 to 1 atm and at a temperature of from 50 to 110 ° C.
13. The method according to claim 11 or 12,
Wherein the roasting of the iron chloride crystals is performed at a temperature of 400 to 1000 ° C.
12. The method of claim 11,
In the nickel smelting process, the solution containing the iron ion and the chloride ion generated in the filtrate
A leaching step of dissolving nickel ore containing Ni and Fe with hydrochloric acid to obtain an leached solution containing Ni and Fe ions;
Adjusting the pH by adding an alkaline agent to the obtained leach solution, and removing the solid impurities from the leach solution by solid-liquid separation;
Adding nickel ore containing Ni and Fe to the leach solution, and precipitating nickel into ferronickel; And
Wherein the filtrate is a filtrate generated in a nickel smelting step including a precipitate recovery step for filtering and recovering solid precipitate by solid-liquid separation.