KR101795893B1 - Method for reduction and leaching of metal ore using ultrasonic wave - Google Patents

Abstract

The present invention provides a method for reducing and leaching nickel and iron containing raw materials using ultrasonic waves and acids. According to the present invention, there is provided a method of leaching nickel and iron-containing raw materials including a step of irradiating ultrasonic waves to nickel and iron-containing raw materials at 10 kHz to 40 kHz and adding an acid to reduce and leach. According to the method of the present invention, the present invention can effectively reduce and leach nickel and iron containing raw materials using ultrasonic waves and acids. Therefore, in the wet smelting process of nickel for producing ferronickel from the conventional nickel and iron-containing raw materials, it is not necessary to perform the reduction process of nickel and iron containing raw materials using a reducing gas such as hydrogen gas, which is performed before the leaching of the nickel- Do not. As a result, not only the process for producing ferronickel is simplified, but it can be efficiently and economically produced.

Description

[0001] METHOD FOR REDUCTION AND LEACHING OF METAL ORE USING ULTRASONIC WAVE [0002]

The present invention relates to a method for reducing and leaching nickel and iron containing raw materials using ultrasonic waves.

Nickel and iron containing ores are limonite and saprolite ore. These ores are oxide states and have passive properties, so they are highly resistant to acids, 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'.

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.

Recently, Korean Patent Laid-Open Publication No. 2009-0031321 proposes a method of economically and efficiently recovering nickel by reducing raw materials containing nickel and iron with hydrogen and leaching into an acid. Also, Korean Patent Laid-Open Publication No. 2013-0076555 discloses a method of reducing a nickel-containing and iron-containing raw material with a reducing gas containing hydrogen to obtain a reducing raw material, and slurries the reducing raw material in an inert atmosphere to prepare a slurry Adding sulfuric acid or hydrochloric acid to the slurry of the 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 and iron ions; The slurry of the reducing raw material for precipitation obtained by reducing the nickel and iron containing raw material into the ion-containing solution is introduced into the nickel and iron ion-containing solution, and the iron of the precipitation reducing raw material is substituted with nickel in the nickel- And a step of precipitating the ferronickel.

As described above, in the conventional method of producing ferronickel from nickel and iron-containing raw materials, metal ores, which are raw materials of nickel and iron, are oxide states. Since these ores are passivated in an oxide state, they are resistant to acids Leaching, which is a dissolution reaction to an acid, does not progress efficiently. Therefore, a separate process has been performed to reduce the metal ores to the reduced light before the metal ores are leached out of the acid so that the leaching reaction using the acid proceeds efficiently, and the reduction process is generally performed using hydrogen gas.

However, when nickel and iron-containing raw materials are effectively leached using an acid without the reduction process of the metal ore which has been carried out in separate stages before the leaching of nickel and iron-containing raw materials using an acid, the efficiency of the ferro- Simplification will enable the production of ferronickel economically and efficiently.

The present invention provides a method for reducing and leaching nickel and iron containing raw materials using ultrasonic waves and acids. The method according to the present invention also provides a method for reducing and leaching metal ores using ultrasonic waves and acids, which does not require reduction treatment of nickel and iron-containing raw materials that have been separately performed before the conventional leaching treatment.

The present invention provides a method of leaching nickel and iron, comprising the step of feeding an acid to nickel and iron-containing raw materials and irradiating ultrasound at 10 kHz to 40 kHz for reduction and leaching.

The leaching step may be performed for 30 minutes to 90 minutes.

The acid may be added in an amount equivalent to 2 to 4 times the leaching equivalent of the metal element in the nickel and iron containing raw materials.

According to the method of the present invention, ultrasound and acid can be used to effectively reduce and leach nickel and iron-containing raw materials. Therefore, in the wet smelting process of nickel for producing ferronickel from the conventional nickel and iron-containing raw materials, it is not necessary to perform the reduction process of nickel and iron containing raw materials using a reducing gas such as hydrogen gas, which is performed before the leaching of the nickel- Do not. As a result, not only the ferronickel production process is simplified, but also ferronickel can be produced efficiently and economically.

Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

According to the present invention, in the wet smelting process of nickel for producing ferronickel from nickel and iron-containing raw materials, nickel and iron containing nickel and iron containing raw materials are reduced and leached with sulfuric acid or hydrochloric acid while irradiating ultrasonic waves A method of leaching raw materials is provided. According to the leaching method of the present invention, leaching rate of nickel and iron containing raw materials by using sulfuric acid or hydrochloric acid is improved by application of ultrasonic energy by local reduction and application of heat. Therefore, there is no need for a reduction treatment of nickel and iron-containing raw materials using a reducing gas before the leaching treatment, for example, hydrogen gas, which has conventionally been performed conventionally.

In addition to the leaching method of the present invention described above, a process generally known as a method for producing ferronickel from nickel and iron-containing raw materials can be applied as needed before and / or after the leaching step according to the present invention. Hereinafter, the method of the present invention will be described in more detail.

The nickel and iron-containing raw materials to which the present invention can be applied are not particularly limited and may be applied as long as they contain nickel and iron. Nickel ores such as nickel and iron, such as limonite and saprophite, Ore.

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

The nickel and iron containing feedstock preferably uses an atomized powder to perform 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 and iron-containing raw materials generally include about 30% to 40% of the number of the bonded particles and about 10% of the crystalline particles. In the case of pulverizing the particles in the state containing such a number of particles, the pulverization efficiency is lowered, Further, when the nickel and iron-containing raw materials are pulverized after being fired, there is a fear that the pulverizing equipment may be loaded due to high temperature. Therefore, it is preferable to dry the nickel and iron-containing raw materials before pulverizing them 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 can be performed by heating to a temperature range of 100 ° C to 200 ° C.

When the nickel and iron-containing raw materials are pulverized after being dried, pulverization of the particles to a size of 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 and iron-containing raw materials 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 and iron-containing raw material, and this moisture slows down the reduction reaction and acts as a factor to lower the reaction efficiency. Therefore, it is preferable to carry out the leaching treatment after removing the crystal water. In order to remove such crystal water, it is preferable to calcine the nickel and iron-containing raw materials.

Among the nickel and iron-containing raw materials, the limonite ore has a property of releasing crystal water at about 250-350 ° C and the saprophorite ore at around 650-750 ° C. Therefore, it is also possible to remove the crystal water contained in the raw material by calcining the nickel and iron-containing raw material powder obtained in the pulverizing step at 250-850 캜.

In addition, if desired, it may be leached after slurrying as in the conventional nickel smelting process.

In the present invention, sulfuric acid or hydrochloric acid is added to nickel and iron-containing raw materials, and ultrasonic waves are applied to dissolve the nickel and iron components contained in the nickel and iron-containing raw materials to obtain nickel and iron-containing leach solutions. At this time, the reduction and leaching of the metal component are simultaneously performed. As described later, as the temperature rises due to the ultrasonic irradiation, reduction and leaching may occur during the firing process during the application of the ultrasonic waves. The reduction and leaching reaction by ultrasonic irradiation and acid addition proceeds as shown in the following reaction formula (1).

Dry light (Fe, Ni) OOH + HCl HCl + ultrasonic _{→ Fe 2 O 3 + NiO +} H 2 O + HCl → Fe 3 O 4 + FeO + NiO + HCl → (Ni, Fe) Cl 2 + H 2 O + H ₂ + HCl (residual)

At this time, the ultrasonic wave is preferably applied at 10 kHz to 40 kHz, preferably 15 kHz to 35 kHz. If it is less than 10 kHz, local reduction for the leaching of Fe and Ni oxide is insufficient due to lack of ultrasonic energy, and if it exceeds 40 kHz, it is undesirable because it is excessive in terms of energy.

By irradiating ultrasonic waves for 30 minutes to 90 minutes, the nickel and iron containing raw materials can be effectively reduced and leached. If less than 30 minutes, reduction and leaching are insufficient, and if it exceeds 90 minutes, excessive energy is not preferable.

When the ultrasonic wave is irradiated, the overall slurry temperature is 200 ° C to 300 ° C. However, the temperature around the particles locally rises to about 1,000 ° C or so. This local exotherm and subsequent reduction results in local reduction around the particles, and nickel and iron elements are leached into the ions by the reaction with acid, the leaching agent.

On the other hand, the hydrochloric acid and sulfuric acid are added in an amount equivalent to 2 to 4 times, preferably 3 times, equivalent to the equivalent of the equivalent amount of the acid required for leaching the metal element in the nickel and iron- . If the amount of hydrochloric acid or sulfuric acid is less than the lower limit, it is not preferable because the leaching rate is lowered, and even if the upper limit is exceeded, the leaching rate is not greatly changed.

The leaching reaction can be carried out at room temperature (15 캜 to 25 캜).

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 nickel and iron-containing raw materials hardly dissolve by 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 .

The iron and nickel ion-containing solution thus obtained can be used for the production of ferronickel by the precipitation reaction. The precipitation reaction may be a general precipitation reaction known in the ferronickel production process.

Hereinafter, the present invention will be described more specifically by way of examples. However, the following examples are for illustrative purposes only and are not intended to limit the present invention.

Example

Hereinafter, the present invention will be described more specifically by way of examples. However, the following examples are for illustrative purposes only and are not intended to limit the present invention.

Pretreatment of raw materials

The limonite ores having the composition as shown in Table 1 below were dried in a rotary kiln at 150 ° C for 1 hour and then pulverized using a super mill to prepare powders. The powders were classified by particle size To obtain a powder having an average particle size of 0.8 mm.

Ni Co Fe Cr Mg Al Si Ca Mn S Cu Zn P Dry light 1.33 0.17 41.51 1.93 3.97 1.41 5.67 0.076 0.94 0.13 <0.01 0.041 <0.01

In Table 1, the content of each component represents weight%, and the remainder is oxygen and other trace components.

Leaching reaction

(1) Ultrasonic application

130 g of hydrochloric acid at a concentration of 8% by weight was added to 30 g of the dried ore powder to prepare a solution. The solution was stirred and ultrasonic waves were applied at 20 kHz for 1 hour to perform reduction and leaching of the ore powder.

In order to confirm the end point of the reaction, the ORP was measured, and it was confirmed that the ORP value changed from - to +, and the reaction was stopped.

The solid residue was separated and removed by solid-liquid separation from the leaching solution obtained by the leaching reaction to obtain a leaching solution of nickel and iron ions. The compositions of leached nickel and iron ion leaching solutions are shown in Table 2 below.

(2) No ultrasound

The iron and nickel ions in the iron and nickel containing raw materials were leached with hydrochloric acid in the same manner as described above except that ultrasonic waves were not applied. The compositions of leached nickel and iron ion leaching solutions are shown in Table 2 below.

                                            (Content unit: 占 퐂 / L) Mg Ca Mn Fe Co Ni Cr Si Al Cu Zn S ultrasonic wave
Unapplied 301 359 113 994 16 231 205 137 324 <10 <10 204 ultrasonic wave
apply 423 357 284 1430 51 309 209 191 422 <10 11 208

As can be seen from the above Table 2, the leaching rate of the Fe component was increased by 43% and the leaching rate of the Ni component was increased by 33% when the ultrasonic wave was applied at the time of leaching. From this, it was confirmed that the leaching rate of Fe and Ni components was increased without the reduction treatment of nickel and iron containing raw materials by using a separate reducing gas by applying ultrasonic waves to the leaching using an acid.

Claims (3)

Adding an acid at room temperature (15 占 폚 to 25 占 폚) to a raw material containing nickel and iron to form a slurry;
Comprising the steps of irradiating ultrasonic waves at 10 kHz to 40 kHz and raising the temperature of the slurry to 200-300 占 폚 to locally reduce nickel and iron of the nickel and iron-
Method of leaching nickel and iron.
The method according to claim 1,
Wherein the leaching is performed for 30 minutes to 90 minutes.
The method according to claim 1,
Wherein the acid is charged in an amount equivalent to 2 to 4 times the leaching equivalent of the metal element in the nickel and iron containing raw materials.