KR101767777B1 - Facility and method for removing and recovering hydrochloric acid in hydrogen gas generated during nickel hydrometallurical extraction process - Google Patents

Abstract

A reducing furnace for reducing nickel ore to hydrogen to obtain reduced nickel ore; A precipitation tank for leaching the reduced nickel ore with hydrochloric acid; And a heat exchanger for cooling and condensing the hydrogen gas containing hydrochloric acid in vapor phase generated from the precipitation tank to obtain hydrogen gas from which hydrochloric acid and hydrochloric acid have been removed and recycling the hydrochloric acid to the leaching tank, A facility for removing and recovering hydrochloric acid from the reactor; And reducing the nickel ore to hydrogen to obtain a reduced nickel ore; Adding hydrochloric acid to the reduced nickel ore to dissolve and leach nickel and iron with ions to obtain a hydrogen gas byproduct containing nickel iron ion-containing solution and vaporous hydrochloric acid; Cooling and condensing the hydrogen gas byproduct to recover vapor phase hydrochloric acid in the hydrogen gas by-product as hydrochloric acid; And recycling the recovered hydrochloric acid to the leaching of the reduced nickel ore. The present invention also provides a method for removing and recovering hydrochloric acid from hydrogen gas in a nickel hydrometallurgical process. According to the facility and method of the present invention, the vapor phase hydrochloric acid in the hydrogen gas generated during the leaching of the reduced nickel ore using hydrochloric acid in the wet smelting process of nickel recovering ferronickel from nickel ore can be efficiently removed and recovered, can do.

Description

FIELD OF THE INVENTION The present invention relates to a method and apparatus for removing and recovering hydrochloric acid in a hydrogen gas generated in a nickel smelting process,

The present invention relates to a facility and a method for removing and recovering hydrochloric acid in hydrogen gas generated in a wet smelting process of nickel recovering ferronickel from nickel ore.

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'.

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 a nickel-containing raw material with hydrogen and leaching into an acid. Also, in Korean Patent Laid-Open Publication No. 2013-0076555, nickel ore is slurried into a nickel-reduced nickel-reduced light which is reduced with hydrogen, and then an acid is added to the slurry to dissolve nickel and iron to obtain a solution containing nickel ions, A nickel ore including nickel nickel ore reducing solution containing nickel ore reduced in hydrogen to a nickel ion-containing solution to replace nickel ions in the nickel ion-containing solution with iron in the nickel reduction light for precipitation and precipitating out with ferro nickel A method for recovering ferronickel was proposed.

In this feronickel recovery step, the ore containing nickel and iron is reduced with hydrogen and the reduced light is leached with an acid to obtain a solution containing nickel and iron, from which feronium is recovered. On the other hand, hydrogen gas is generated upon leaching using an acid, and the hydrogen gas includes vapor phase hydrochloric acid, hydrogen sulfide, moisture, and the like. The monitoring of the concentration of hydrochloric acid in the hydrogen gas from the settling tank results in an average of 30,000 ppm, and this hydrochloric acid should be removed for hydrogen gas recycling.

Since hydrogen is an expensive substance used as a reducing gas in the wet smelting process of nickel, vapor phase hydrochloric acid and / or hydrogen sulfide impurities in the hydrogen gas generated upon leaching using the acid can be removed and then recycled as a reducing gas. Such impurities have conventionally been removed by adsorbing hydrochloric acid and / or hydrogen sulfide to ion exchange fibers provided in the ion exchange scrubber by passing hydrogen vapor containing hydrogen and hydrogen sulfide through the ion exchange scrubber. On the other hand, the ion exchange fiber adsorbed with hydrochloric acid and / or hydrogen sulfide has been regenerated by using caustic soda. However, since hydrogen gas contains a large amount of hydrochloric acid and / or hydrogen sulfide, there is a problem that a large amount of caustic soda is required for regeneration of the ion exchange fiber.

Accordingly, there is a need for a method that can efficiently remove, recover and recycle hydrochloric acid from hydrogen gas containing a large amount of hydrochloric acid generated in the nickel wet smelting process.

The present invention provides a facility for removing, recovering and reusing hydrochloric acid in hydrogen gas generated in the wet smelting process of nickel recovering ferronickel from nickel ore.

The present invention provides a method for removing, recovering and reusing hydrochloric acid in a hydrogen gas generated in a wet smelting process of nickel recovering ferronickel from nickel ore.

According to one aspect of the present invention,

A reducing furnace for reducing nickel ore to hydrogen to obtain reduced nickel ore;

A precipitation tank for leaching the reduced nickel ore with hydrochloric acid; And

And a heat exchanger for cooling and condensing the hydrogen gas containing hydrochloric acid in vapor phase generated from the precipitation tank to obtain hydrogen gas from which hydrochloric acid and hydrochloric acid have been removed and recycling the hydrochloric acid to the leaching tank. A facility for removing and recovering hydrochloric acid is provided.

The inside of the heat exchanger may be made of acid-resistant titanium or FRP material.

And a condenser for supplying the refrigerant to the heat exchanger.

And may further include a mist removing the droplet in the hydrogen gas passing through the heat exchanger and discharging the hydrogen gas from which the vapor-phase hydrochloric acid has been removed.

The hydrogen gas discharged from the demister may be recycled to the reducing furnace.

A temperature sensor may be further included at a front end of the heat exchanger and at a rear end of the heat exchanger or the demister.

And may further include a pressure sensor at a front end of the heat exchanger and at a rear end of the heat exchanger or the demister.

An ion exchange scrubber may be further included at the rear end of the demister.

According to another aspect of the present invention,

Reducing the nickel ore to hydrogen to obtain a reduced nickel ore;

Introducing hydrochloric acid into the reduced nickel ore to dissolve and leach nickel and iron with ions to obtain a hydrogen gas byproduct containing nickel iron ion-containing solution and vaporous hydrochloric acid;

Cooling and condensing the hydrogen gas byproduct to recover the vapor phase hydrochloric acid in the hydrogen gas by-product as hydrochloric acid; And

There is provided a method for removing and recovering hydrochloric acid from hydrogen gas in a nickel hydrometallurgical process comprising reusing recovered hydrochloric acid for leaching of the reduced nickel ore.

The temperature drop of the hydrogen gas during the condensation may be 20 ° C to 50 ° C.

The method may further include the step of reusing hydrochloric acid removed and recovered hydrogen gas for reduction of nickel ore.

According to the plant and method of the present invention, vapor phase hydrochloric acid in the hydrogen gas generated during the leaching of the reduced nickel ore using hydrochloric acid in the wet smelting process of nickel recovering ferronickel from nickel ore is efficiently removed and recovered. In addition, the recovered hydrochloric acid is economical since it can be reused for the leaching of the reduced nickel ore. Further, since most of the hydrochloric acid contained in the hydrogen gas is removed, the amount of caustic soda used in the ion exchange scrubber for removing impurities in the hydrogen gas can be reduced, and furthermore, the amount of the acidic substance to be removed is reduced. It is possible to reduce the size and the equipment cost. Hydrogen gas with hydrochloric acid removed can be reused for the reduction of nickel ore. Removal of hydrochloric acid also prevents corrosion of the installation.

1 schematically shows a facility for removing and recovering hydrochloric acid from hydrogen gas in a nickel wet smelting process of the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. 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.

In the wet nickel smelting process for feronickel recovery, nickel ore is reduced with a reducing gas to obtain a reduced nickel ore, and then nickel ore contained in the reduced nickel ore is removed by leaching the reduced nickel ore using an acid. To obtain a solution containing nickel iron ion. When the reduced nickel ore is added to the thus obtained solution, a substitution reaction occurs between the nickel ion in the solution and the metal iron in the reduced nickel ore, and ferronickel precipitates.

As the reducing gas, hydrogen gas may be generally used. Hydrochloric acid is generally used as the acid in the leaching of the reducing light. For example, when nickel ore is reduced using hydrogen as a reducing gas, reduced light is obtained by a theoretical reduction reaction as shown in the following formula (1). When such a reduction light is leached out with hydrochloric acid, the metal iron and nickel in the reducing raw material are dissolved by the acid, and are leached into iron and nickel ions, and hydrogen gas is generated by reacting as shown in the following reaction formula (2).

The leaching reaction using hydrochloric acid can be carried out in a solution at room temperature of about 20 ° C or in a heated state. Such an acid leaching reaction is an exothermic reaction accompanied by an increase in temperature in the reactor, and hydrogen generated in the leaching tank is at a temperature of about 50 ° C or more, about 50 ° C to 60 ° C, even if an acid leaching reaction is carried out at room temperature. Therefore, in the hydrogen, vapor phase hydrochloric acid, hydrogen sulfide, and water vapor derived from the slurry upon leaching are discharged together with hydrogen. Therefore, it is necessary to remove the vapor phase hydrochloric acid and water vapor from the hydrogen gas to be discharged. It is also preferable that the hydrochloric acid is recovered and reused for leaching of the reduced light.

According to one aspect of the present invention, there is provided a facility for removing and recovering vaporous hydrochloric acid with hydrochloric acid from hydrogen gas generated during acid precipitation of reduced light. An example of a facility for removing and recovering vapor phase hydrochloric acid from the hydrogen gas provided by the present invention with hydrochloric acid is shown in FIG.

The facility for removing and recovering hydrochloric acid from hydrogen gas in the nickel hydrometallurgical process according to the present invention comprises a reducing furnace 1 for obtaining reduced nickel ore by reducing nickel ore to hydrogen and a precipitation tank for leaching the reduced nickel ore with hydrochloric acid 2), and a heat exchanger (3) for cooling and condensing the hydrogen gas containing vapor phase hydrochloric acid generated from the precipitation tank to obtain hydrogen gas from which hydrochloric acid and vapor-phase hydrochloric acid have been removed, and recycling the hydrochloric acid to the leaching tank .

The facility for removing and recovering hydrochloric acid from the hydrogen gas according to the present invention comprises a condenser 4 for supplying a refrigerant to the heat exchanger 3 and a condenser 4 for collecting the hydrochloric acid and recirculating the hydrochloric acid to the precipitation tank 2, And may further include a mist (5) and a mister (6) for removing droplets from the hydrogen gas passing through the heat exchanger and discharging hydrogen gas.

In the reduction furnace (1), a nickel ore in which nickel ore is reduced by the reaction of nickel ore and hydrogen is obtained. Thereafter, hydrochloric acid is added to the nickel ore reduced in the sedimentation tank 2 to remove the hydrogen gas by-products including nickel iron ion-containing solution (leach solution), vapor phase hydrochloric acid, and water vapor dissolved and leached with nickel and iron ions, Is obtained.

Ferronickel is obtained from the leaching solution containing iron and nickel, and the residue is discarded. The hydrogen gas containing the vapor phase hydrochloric acid and the water vapor is introduced into the heat exchanger 3 and is cooled and condensed. As the hydrogen gas is cooled and condensed, the vapor pressure of the vapor phase hydrochloric acid and water vapor contained in the hydrogen gas is changed, so that the saturation concentration of the vapor and the vapor phase hydrochloric acid is rapidly lowered and the water vapor condenses into water. On the other hand, since hydrochloric acid is well soluble in water, the vapor phase hydrochloric acid is dissolved in water and recovered as hydrochloric acid.

It is preferable that the temperature of the hydrogen gas is lowered by 20 캜 to 50 캜 through the heat exchanger 3. If the temperature drop is less than 20 캜, the amount of hydrochloric acid to be removed and recovered from the hydrogen gas dissolved in water is small, and if the temperature drop exceeds 50 캜, the saturated water vapor pressure of hydrochloric acid is relatively high at that temperature, It is not preferable. For example, the hydrogen gas containing vapor phase hydrochloric acid and water vapor introduced in the heat exchanger 3 is at a temperature of 50 to 60 DEG C and can be cooled to 0 to 40 DEG C in the heat exchanger 3. [

For example, when the concentration of hydrochloric acid used in the sedimentation tank 2 is 20 wt% and the temperature is 60 DEG C, the saturated vapor pressure of hydrochloric acid in the hydrogen gas is 4.2 mmHg, and 0.55 vol% of hydrochloric acid fume is generated . When the hydrogen gas is cooled to 10 ° C, the saturated vapor pressure of hydrochloric acid is reduced to 0.07 mmHg, and the hydrochloric acid concentration is reduced to 92 ppm, thereby theoretically 99% hydrochloric acid can be recovered.

The inside of the heat exchanger (3) is made of an acid-resistant titanium Or an FRP (glass fiber reinforced plastic) material.

On the other hand, the apparatus according to one aspect of the present invention may further include a condenser 4 for supplying the refrigerant to the heat exchanger 3. As the refrigerant, any refrigerant generally used in general use may be used, and a mixture of water and ethylene glycol may be used although not limited thereto. In the mixture of water and ethylene glycol, water and ethylene may be mixed in a weight ratio of 1: 1. Further, the refrigerant used in the heat exchanger 3 can be recycled to the condenser 4, condensed by heat exchange in the condenser 4, and then supplied to the heat exchanger 3 again.

The hydrochloric acid formed by the cooling condensation in the heat exchanger (3) can be recycled to the precipitation tank (2) and reused for leaching of the reduced light. The recovered hydrochloric acid may be collected in the hydrochloric acid recovery tank 5 and recycled to the precipitation tank 2. The recovered hydrochloric acid can be recycled to the precipitation tank 2 by concentration as necessary. In addition, the hydrogen gas from which the vapor phase hydrochloric acid discharged from the heat exchanger 3 has been removed can be recycled to the reducing furnace 1.

The rear end of the heat exchanger 3 may further include a mist 6 for removing droplets from the hydrogen gas discharged from the heat exchanger 3 and discharging hydrogen gas.

The temperature sensor (t) and (t ') are further included in the front end of the heat exchanger (3) and the rear end of the heat exchanger (3) or the demister (6) And the temperature difference between the hydrogen gas discharged from the demister 6 and the hydrogen gas discharged from the demister 6 can be maintained at 20 ° C to 50 ° C as described above.

Furthermore, the pressure sensor (p ') and the pressure sensor (p') are further included at the front end of the heat exchanger 3 and at the rear end of the heat exchanger 3 or the demister 6 to be introduced into the heat exchanger 3 And the pressure of the hydrogen gas discharged from the demister 6 can be monitored. That is, it is possible to monitor the pressure required for the reuse of the hydrogen gas by the pressure sensors (p) and (p '), and whether the pressure drop occurs due to clogging or the like during the process. The positions of the temperature sensors t and t 'and the pressure sensors p and p' are not particularly limited.

Further, at the rear end of the demister 6, an ion exchange scrubber 7 used for removing impurities in conventional hydrogen gas may be further included.

The hydrogen gas discharged from the heat exchanger 3 is recycled to the reducing furnace 1 after removing the H ₂ S from the demister 6 and the ion exchange scrubber 7 at the subsequent stage to be reused for reduction of the nickel ore have.

The facility and method for removing and recovering hydrochloric acid in the hydrogen gas generated in the wet smelting process of nickel recovering ferronickel from the nickel ore according to the present invention are mainly focused on components related to the removal and recovery of hydrochloric acid in the hydrogen gas , And a configuration known in the art of nickel smelting processes can generally be included in the practice of the present invention.

Example

Hereinafter, a hydrogen recovery method according to the present invention will be described by way of examples. The following examples are provided to illustrate that the present invention can be applied, and the present invention is not limited thereto.

Pre-treatment of ore

The limonite ores having a composition as shown in Table 1 were dried in a rotary kiln at 150 ° C for 1 hour and then pulverized using a super mill to prepare powders. Powders were classified by particle size A powder having a particle size of 0.8 mm was obtained. The obtained powder was fired in a firing furnace maintained at 300 캜 for 1 hour to remove crystal water from the ore powder.

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

Ni Fe Mg Si Al Rimonite 1.4 42.3 1.1 1.1 2.5 Reduction light 2.0 60.5 1.65 1.6 3.6

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

The thus-prepared reduced light was cooled in an oxygen-free tank filled with nitrogen gas, and 200 ml of water was added to 200 g of the reduced light to prepare a slurry.

Production of reducing raw materials

The pretreated nickel light was discharged from a firing furnace and charged into a rotary kiln reduction furnace 1 in which oxygen was shut off. Thereafter, hydrogen of 4 times the mole number of the (Ni + Fe) mole contained in the prepared ore powder was used Reduced light was produced by reducing the ore at 725 ° C. The thus-prepared reduced light was cooled in an oxygen-free tank filled with nitrogen gas, and 200 ml of water was added to 200 g of the reduced light to prepare a slurry.

Leaching reaction

Hydrochloric acid was added to the slurry in a slurry at a concentration of 20% by weight in the slurry prepared in the sedimentation tank 2 at room temperature to prepare a 1-L solution and stirred to dissolve the reduced light to precipitate ferric ions A leaching reaction was carried out. As a result, residues, leaching solution and hydrogen gas were generated.

Vapor phase  Removal and recovery of hydrochloric acid

The temperature of the hydrogen gas generated in the leaching reaction was 50 DEG C due to the exothermic reaction. The hydrogen gas is introduced into the heat exchanger 3 and a refrigerant in which water and ethylene glycol are mixed at a ratio of 1: 1 is introduced into the heat exchanger 3 from the condenser 4 so that the temperature difference between the front and rear ends of the heat exchanger 3 (With a shearing temperature of 50 캜 and a rear stage temperature of 20 캜) so as to maintain the temperature at 30 캜. As a result, 85 vol% of hydrochloric acid was removed from the hydrogen gas discharged from the rear end of the heat exchanger 3.

The temperature difference between the front end and the rear end was maintained at 40 캜 (shear temperature 50 캜 and rear end temperature 10 캜). As a result, 95 vol% of hydrochloric acid was removed from the hydrogen gas discharged from the rear end of the heat exchanger 3.

The recovered hydrochloric acid was reused in the precipitation tank (2).

1 ... Reduction furnace 2 ... Settling tank
3 ... heat exchanger 4 ... condenser
5 ... hydrochloric acid recovery tank 6 ... demister
7 ... ion exchange scrubber t, t '... temperature sensor
p, p '... Pressure sensor

Claims (11)

A reducing furnace for reducing nickel ore to hydrogen to obtain reduced nickel ore;
A precipitation tank for leaching the reduced nickel ore with hydrochloric acid; And
A heat exchanger for cooling and condensing the hydrogen gas containing hydrochloric acid in vapor phase generated from the precipitation tank to obtain hydrogen gas from which hydrochloric acid and hydrochloric acid have been removed, and recycling the hydrochloric acid to the leaching tank,
The apparatus for removing and recovering hydrochloric acid from hydrogen gas in a nickel wet smelting process wherein the temperature drop of the hydrogen gas during the cooling and condensing is 20 ° C to 50 ° C.
The method according to claim 1,
The inside of the heat exchanger is made of an acid-resistant titanium Or equipment for recovering hydrochloric acid from hydrogen gas in a nickel hydrometallurgical process consisting of FRP material.
The method according to claim 1,
And a condenser for supplying a refrigerant to the heat exchanger. The apparatus for recovering hydrochloric acid from hydrogen gas in a nickel-hydrometallurgical process.
The method according to claim 1,
An apparatus for recovering hydrochloric acid from a hydrogen gas in a nickel hydrometallurgical process, further comprising a mist removing the droplet in the hydrogen gas passing through the heat exchanger and discharging the hydrogen gas from which the vapor phase hydrochloric acid has been removed.
5. The method of claim 4,
Wherein the hydrogen gas discharged from the demister is recycled to the reducing furnace, and the hydrochloric acid is recovered from the hydrogen gas in the nickel smelting process.
5. The method of claim 4,
And a temperature sensor at the front end of the heat exchanger and at a rear end of the heat exchanger or the demister, for recovering hydrochloric acid from the hydrogen gas in a nickel wet smelting process.
5. The method of claim 4,
An apparatus for recovering hydrochloric acid from hydrogen gas in a nickel wet smelting process further comprising a pressure sensor at a front end of the heat exchanger and at a rear end of the heat exchanger or the demister.
5. The method of claim 4,
An apparatus for recovering hydrochloric acid from hydrogen gas in a nickel wet smelting process further comprising an ion exchange scrubber at the downstream of the demister.
Reducing the nickel ore to hydrogen to obtain a reduced nickel ore;
Introducing hydrochloric acid into the reduced nickel ore to dissolve and leach nickel and iron with ions to obtain a hydrogen gas byproduct containing nickel iron ion-containing solution and vaporous hydrochloric acid;
Cooling and condensing the hydrogen gas byproduct to recover vapor phase hydrochloric acid in the hydrogen gas by-product as hydrochloric acid; And
And reusing the recovered hydrochloric acid for leaching of the reduced nickel ore,
Wherein during the cooling and condensing, the temperature drop of the hydrogen gas is 20 deg. C to 50 deg. C, and the hydrochloric acid is removed and recovered from the hydrogen gas in the nickel wet smelting process.
delete 10. The method of claim 9,
Further comprising the step of reusing hydrochloric acid removed and recovered hydrogen gas for reduction of nickel ore, and removing and recovering hydrochloric acid from the hydrogen gas in a nickel hydrometallurgical process.

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