WO2015114913A1

WO2015114913A1 - Sulfide-manufacturing facility and process

Info

Publication number: WO2015114913A1
Application number: PCT/JP2014/080426
Authority: WO
Inventors: 英一中川
Original assignee: 住友金属鉱山株式会社
Priority date: 2014-01-28
Filing date: 2014-11-18
Publication date: 2015-08-06
Also published as: AU2014380678A1; JP5807689B2; PH12016501121A1; PH12016501121B1; AU2014380678B2; JP2015140448A

Abstract

Provided are: a sulfide-manufacturing facility which can attain effective utilization of hydrogen sulfide gas and thus improve the reaction efficiency of hydrogen sulfide; and a sulfide-manufacturing process. This sulfide-manufacturing facility is provided with: a sulfidation vessel (1) to which a reaction start liquid (11), hydrogen sulfide gas (12) and a sodium hydrogen sulfide-containing aqueous solution (13) are supplied; a reaction finish liquid reserving tank (2) to which a reaction finish liquid (14) is supplied; a first gas washing tower (3) in which hydrogen sulfide gas (17) discharged from the sulfidation vessel (1) is absorbed by an aqueous sodium hydroxide solution (19); a second gas washing tower (4) in which hydrogen sulfide gas (21) discharged from the reaction finish liquid reserving tank (2) is absolved by an aqueous sodium hydroxide solution (20) discharged from the first gas washing tower; and a circulating system (6) for supplying a sodium hydrogen sulfide-containing aqueous solution (13) discharged from the second gas washing tower (4) to the sulfidation vessel (1). Thus, the hydrogen sulfide gas (17,21) can be effectively utilized, whereby the reaction efficiency of hydrogen sulfide can be improved.

Description

Sulfide production equipment and method

The present invention relates to a sulfide production facility and method. More specifically, the present invention relates to a production facility and a production method for producing a sulfide of a valuable metal by adding a sulfiding agent to a sulfuric acid aqueous solution containing the valuable metal.

As a method for selectively recovering valuable metals contained in a sulfuric acid aqueous solution containing impurities, a method of adding a sulfiding agent to a sulfuric acid aqueous solution and precipitating the valuable metals as sulfides by a sulfurization reaction is known. As the sulfiding agent, for example, hydrogen sulfide gas or alkali sulfide is used.

In the method using hydrogen sulfide gas as the sulfiding agent, unreacted hydrogen sulfide gas is discharged. Since hydrogen sulfide gas is a toxic gas, it needs to be removed. Moreover, since the sulfidation reaction by hydrogen sulfide gas produces an acid, the pH of the reaction solution is lowered. When the pH of the reaction solution is lower than a specific value, sulfide re-dissolution occurs and the sulfurization reaction does not proceed. Therefore, in order to advance the sulfidation reaction efficiently, the decrease in pH is controlled by adjusting the valuable metal concentration of the reaction solution below a specific concentration, or the sulfidation reaction is carried out while neutralizing the generated acid by adding alkali. Something goes on.

In the method using an alkali sulfide (for example, sodium hydrosulfide, sodium sulfide) as a sulfiding agent, the alkali sulfide is chemically stable and can be used easily without requiring a large scale detoxification facility. Further, since the alkali sulfide itself is alkaline, unlike the method using hydrogen sulfide gas, there is an advantage that the pH of the reaction solution is not lowered and the re-dissolution of the sulfide accompanying this does not occur. Therefore, sulfide can be recovered with high yield.

Patent Document 1 discloses a method for producing a nickel / cobalt mixed sulfide. As shown in FIG. 8, a reaction starting solution 101 made of a sulfuric acid aqueous solution containing nickel and cobalt is introduced into a reaction vessel 109. An aqueous solution 103 containing hydrogen sulfide gas 102 and sodium hydrosulfide as a sulfiding agent is supplied to the reaction vessel 109. In the reaction vessel 109, a sulfidation reaction of nickel and cobalt occurs, and a reaction final solution 104 containing nickel / cobalt mixed sulfide is discharged. The exhaust gas 105 discharged from the reaction vessel 109 contains unreacted hydrogen sulfide gas. The exhaust gas 105 is processed by the gas cleaning tower 107 and the detoxified gas is released into the atmosphere 108. In the gas cleaning tower 107, an aqueous sodium hydroxide solution 106 is used as an absorbing solution, and the hydrogen sulfide gas in the exhaust gas 105 is recovered to obtain an aqueous solution 103 containing sodium hydrosulfide. This aqueous solution 103 is repeated in the reaction vessel 109 as a sulfiding agent. Thereby, the utilization efficiency of hydrogen sulfide gas can be improved and nickel and cobalt can be recovered in a high yield.

However, in the above conventional method, it was practically difficult to repeat the entire amount of the aqueous solution 103 containing sodium hydrosulfide in the reaction vessel 109. In the conventional method, since the aqueous solution 103 is directly transferred from the gas cleaning tower 107 to the reaction vessel 109, the supply amount of hydrogen sulfide gas to the gas cleaning tower 107 is large, and the generated amount of the aqueous solution 103 is supplied to the reaction vessel 109. If the amount is larger than the amount, it is necessary to send the surplus aqueous solution 103 to a wastewater treatment process outside the system to reduce the amount of liquid.

Further, part of the hydrogen sulfide dissolved in the reaction final solution 104 is discharged as a gas when it is discharged from the reaction vessel 109 and the temperature and pressure drop. However, since the amount of hydrogen sulfide gas discharged from the reaction final solution 104 is small, it was processed without being reused.
Thus, in the conventional method, hydrogen sulfide gas has not been effectively used.

JP 2010-126778 A

In view of the above circumstances, an object of the present invention is to provide a sulfide manufacturing facility and a manufacturing method capable of improving hydrogen sulfide reaction efficiency by effectively using hydrogen sulfide gas.

The sulfide production facility of the first invention is supplied with a sulfuric acid aqueous solution containing a valuable metal as a reaction starting liquid, and is supplied with an aqueous solution containing hydrogen sulfide gas and sodium hydrosulfide as a sulfiding agent. A sulfurization reaction vessel for generating a product, a reaction final solution storage tank to which a reaction final solution discharged from the sulfurization reaction vessel is supplied, and absorption of hydrogen sulfide gas discharged from the sulfurization reaction vessel by an aqueous sodium hydroxide solution A first gas cleaning tower to be absorbed by the liquid, a second gas cleaning tower to absorb the hydrogen sulfide gas discharged from the reaction final liquid storage tank into the absorbing liquid discharged from the first gas cleaning tower, and the first A circulation device for supplying the absorption liquid discharged from the two-gas cleaning tower to the sulfurization reaction vessel as an aqueous solution containing the sodium hydrosulfide.
In the sulfide production facility according to a second aspect of the present invention, in the first aspect, the circulation device includes a sodium hydrosulfide storage tank for temporarily storing the aqueous solution containing the sodium hydrosulfide discharged from the second gas cleaning tower. It is characterized by.
In the sulfide production facility according to a third aspect of the present invention, in the first or second aspect, the reaction starting liquid is nickel obtained by removing impurities from a leachate obtained by leaching a slurry containing nickel oxide ore with sulfuric acid. It is a mother liquid for collection.
According to a fourth aspect of the present invention, there is provided a sulfide production method comprising: supplying an aqueous solution containing hydrogen sulfide gas and sodium hydrosulfide as a sulfiding agent to a sulfuric acid aqueous solution containing a valuable metal as a reaction starting solution; An aqueous solution containing sodium hydrosulfide by absorbing the unreacted hydrogen sulfide gas in the sulfurization reaction and the hydrogen sulfide gas discharged from the reaction final solution of the sulfurization reaction in an absorption liquid composed of an aqueous sodium hydroxide solution The aqueous solution containing the obtained sodium hydrosulfide is supplied to the reaction starting solution.
The sulfide production method of the fifth invention is characterized in that, in the fourth invention, the aqueous solution containing sodium hydrosulfide is temporarily stored and then supplied to the reaction starting solution.
According to a sixth aspect of the present invention, there is provided the method for producing a sulfide according to the fourth or fifth aspect, wherein the reaction starting solution is nickel obtained by removing impurities from a leachate obtained by leaching a slurry containing nickel oxide ore with sulfuric acid. It is a mother liquid for collection.

According to the first invention, in addition to the unreacted hydrogen sulfide gas in the sulfidation reaction, the hydrogen sulfide gas discharged from the reaction final solution is also absorbed by the aqueous sodium hydroxide solution to produce sodium hydrosulfide to the sulfidation reaction vessel. Since it repeats, hydrogen sulfide gas can be used effectively. As a result, the supply amount of sodium hydrosulfide increases, so that the hydrogen sulfide reaction efficiency can be improved. Moreover, since the absorption liquid obtained from the 1st gas washing tower is used in the 2nd gas washing tower, the usage-amount of sodium hydroxide aqueous solution can be reduced and a sodium hydroxide basic unit can be reduced.
According to the second invention, since the aqueous solution containing sodium hydrosulfide is temporarily stored, when the generated amount of the aqueous solution containing sodium hydrosulfide is larger than the supply amount to the sulfurization reaction vessel, the surplus can be stored. When the amount of the aqueous solution containing sodium hydrosulfide is smaller than the amount supplied to the sulfurization reaction vessel, the temporarily stored aqueous solution containing sodium hydrosulfide can be supplied to the sulfurization reaction vessel. As a result, the entire amount of sodium hydrosulfide can be repeated in the sulfurization reaction vessel, and the supply amount of sodium hydrosulfide increases, so that the hydrogen sulfide reaction efficiency can be improved.
According to the third invention, nickel sulfide can be recovered with high yield.
According to the fourth aspect of the invention, in addition to the unreacted hydrogen sulfide gas in the sulfurization reaction, the hydrogen sulfide gas discharged from the reaction final solution is also absorbed by the sodium hydroxide aqueous solution to produce sodium hydrosulfide to the sulfurization reaction vessel. Since it repeats, hydrogen sulfide gas can be used effectively. As a result, the supply amount of sodium hydrosulfide increases, so that the hydrogen sulfide reaction efficiency can be improved.
According to the fifth invention, since the aqueous solution containing sodium hydrosulfide is temporarily stored, the surplus can be stored when the amount of the aqueous solution containing sodium hydrosulfide is larger than the supply amount to the reaction starting liquid. When the generated amount of the aqueous solution containing sodium hydrosulfide is smaller than the supply amount to the reaction start solution, the temporarily stored aqueous solution containing sodium hydrosulfide can be supplied to the reaction start solution. As a result, the total amount of sodium hydrosulfide can be repeated in the reaction starting solution, and the supply amount of sodium hydrosulfide increases, so that the hydrogen sulfide reaction efficiency can be improved.
According to the sixth invention, nickel sulfide can be recovered with high yield.

It is explanatory drawing of the manufacturing facility of the sulfide which concerns on one Embodiment of this invention. It is a whole process figure of a wet smelting method. 3 is an explanatory diagram of a sulfide production facility in Comparative Example 1. FIG. It is a graph which shows the relationship between a sodium hydrosulfide addition ratio and nickel poor solution pH. It is a graph which shows the relationship between a sodium hydrosulfide addition ratio and nickel recovery. It is a graph which shows the relationship between a sodium hydrosulfide addition ratio and hydrogen sulfide reaction efficiency. It is a graph which shows the relationship between a sodium hydrosulfide addition ratio and sodium hydroxide basic unit. It is explanatory drawing of the conventional manufacturing equipment.

Next, an embodiment of the present invention will be described with reference to the drawings.
(Wet smelting)
First, the hydrometallurgical process for obtaining nickel / cobalt mixed sulfide from nickel oxide ore will be described.
High pressure acid leaching (HPAL) is a high pressure acid leaching method (HPAL) as a hydrometallurgical process for recovering valuable metals such as nickel and cobalt from low-grade nickel oxide ores such as limonite ore. A sulfuric acid leaching method is known.

As shown in FIG. 2, in the hydrometallurgy by the high temperature pressure sulfuric acid leaching method, the pretreatment step (1), the high temperature pressure sulfuric acid leaching step (2), the solid-liquid separation step (3), neutralization A process (4), a dezincing process (5), a sulfurization process (6), and a detoxification process (7) are included.

In the pretreatment step (1), nickel oxide ore is crushed and classified to produce ore slurry. In the high temperature pressure sulfuric acid leaching step (2), sulfuric acid is added to the ore slurry obtained in the pretreatment step (1), and stirred at 220 to 280 ° C. to obtain high temperature pressure acid leaching to obtain a leaching slurry. In the solid-liquid separation step (3), the leaching slurry obtained in the high-temperature pressurized sulfuric acid leaching step (2) is subjected to solid-liquid separation to obtain a leaching solution (crude nickel sulfate aqueous solution) containing nickel and cobalt and a leaching residue.

In the neutralization step (4), the crude nickel sulfate aqueous solution obtained in the solid-liquid separation step (3) is neutralized. In the zinc removal step (5), hydrogen sulfide gas is added to the crude nickel sulfate aqueous solution neutralized in the neutralization step (4) to precipitate and remove zinc as zinc sulfide. In the sulfiding step (6), a sulfiding agent is added to the nickel recovery mother liquor obtained in the dezincing step (5) to obtain a nickel / cobalt mixed sulfide and a nickel poor solution. In the detoxification step (7), the leaching residue generated in the solid-liquid separation step (3) and the nickel poor solution generated in the sulfidation step (6) are detoxified.

The sulfide production facility and method according to an embodiment of the present invention are preferably applied to the sulfurization step in the above-described hydrometallurgy. That is, a nickel recovery mother liquor obtained by removing impurities such as zinc from a leachate (crude nickel sulfate aqueous solution) obtained by sulfuric acid leaching of a slurry containing nickel oxide ore was used as a reaction start liquid. A sulfurizing agent is added to precipitate nickel and cobalt contained in the reaction starting solution as a nickel / cobalt mixed sulfide by a sulfurization reaction.

The total concentration of nickel and cobalt in the mother liquor for nickel recovery is not particularly limited, but is usually 2 to 6 g / L. Here, the nickel concentration is 2 to 5 g / L, and the cobalt concentration is 0.1 to 0.6 g / L.

The reaction starting solution is not limited to the mother liquor for recovering nickel, and may be an aqueous sulfuric acid solution containing valuable metals such as nickel and cobalt.

(Manufacturing equipment, manufacturing method)
Next, a sulfide production facility A according to an embodiment of the present invention and a sulfide production method using the production facility A will be described.
As shown in FIG. 1, the manufacturing facility A according to the present embodiment includes a sulfurization reaction vessel 1, a reaction final solution storage tank 2, a first gas cleaning tower 3, a second gas cleaning tower 4, and sodium hydrosulfide. And a storage tank 5.

The sulfurization reaction vessel 1 is a pressure type reaction vessel having pressure resistance. The sulfurization reaction vessel 1 is supplied with a nickel recovery mother liquor (a sulfuric acid aqueous solution containing nickel and cobalt) as a reaction starting solution 11. Further, an aqueous solution 13 containing hydrogen sulfide gas 12 and sodium hydrosulfide as a sulfiding agent is supplied.

Note that the sulfurization reaction vessel 1 is not limited to one, and a plurality of, for example, four sulfurization reaction vessels 1 may be connected in series to continuously perform a sulfurization reaction.

As shown in the following chemical formula 1, when hydrogen sulfide gas 12 is supplied to the reaction start liquid 11, nickel and cobalt in the reaction start liquid 11 are converted into nickel sulfide and cobalt sulfide by the sulfurization reaction of hydrogen sulfide (H ₂ S). And precipitate. Further, sulfuric acid (H ₂ SO ₄ ) is generated by the reaction of Chemical Formula 1.
(Chemical formula 1)
MSO ₄ + H ₂ S → MS + H ₂ SO ₄ (wherein M represents Ni, Co)

When the aqueous solution 13 containing sodium hydrosulfide is supplied to the reaction start liquid 11, the sulfuric acid produced by the reaction of Chemical Formula 1 is neutralized by sodium hydrosulfide (NaSH) by the neutralization reaction of Chemical Formula 2 below. At the same time, nickel and cobalt in the reaction starting solution 11 are precipitated as nickel sulfide and cobalt sulfide by the sulfurization reaction with sodium hydrosulfide of the chemical formula 3 below.
(Chemical formula 2)
H ₂ SO ₄ + 2NaSH → Na ₂ SO ₄ + 2H ₂ S
(Chemical formula 3)
MSO ₄ + 2NaSH → Na ₂ SO ₄ + MS + H ₂ S (M in the formula represents Ni or Co)

By supplying the aqueous solution 13 containing sodium hydrosulfide to the reaction start liquid 11, the sulfuric acid produced by the reaction of Chemical Formula 1 is neutralized, and at the same time, sulfide is produced by the sulfurization reaction with sodium hydrosulfide, so that the pH is lowered. Can be suppressed. As a result, nickel sulfide and cobalt sulfide can be recovered with high yield. As a result, a nickel recovery rate of 97.5% or more can be realized.

Thus, when the aqueous solution 13 containing the hydrogen sulfide gas 12 and sodium hydrosulfide is supplied to the reaction start liquid 11, a sulfurization reaction occurs and nickel / cobalt mixed sulfide is generated.

Note that the pressure in the sulfurization reaction vessel 1 is not particularly limited, but is preferably 100 to 300 kPa in order to promote the sulfurization reaction of nickel and cobalt. In addition, it is efficient to use the sulfurization reaction vessel 1 connected in multiple stages. In this case, the first stage is 250 to 300 kPa, the pressure is gradually reduced, and the final stage is 100 to 150 kPa. Is preferred. Thereby, hydrogen sulfide gas is efficiently used for the sulfurization reaction.

The pH of the reaction starting solution 11 is not particularly limited, but is preferably 3.0 to 3.8 in order to promote the sulfurization reaction of nickel and cobalt. This is because if the pH of the reaction starting solution 11 is less than 3.0, iron, aluminum, and the like cannot be sufficiently removed in the previous neutralization step. On the other hand, if the pH of the reaction starting solution 11 exceeds 3.8, nickel or cobalt hydroxide may be generated.

The temperature of the reaction starting solution 11 is not particularly limited, but is preferably 65 to 90 ° C. The sulfidation reaction itself is generally promoted at a higher temperature. However, when the temperature exceeds 90 ° C., there is a problem that the temperature rises, and there is a risk that sulfide is attached to the sulfidation reaction vessel 1 because the reaction rate is fast. There is a problem that there is.

Although the supply amount of the hydrogen sulfide gas 12 is not particularly limited, it is necessary for sulfiding the nickel and cobalt contained in the reaction start liquid 11 according to chemical formula 1 in order to recover nickel and cobalt as sulfides in a desired high yield. The reaction equivalent is preferably about 1.0 to 1.1 times. Excessive addition beyond this leads to an increase in unreacted hydrogen sulfide gas discharged from the sulfurization reaction vessel 1.

The reaction end solution 14 containing the nickel / cobalt mixed sulfide generated by the sulfidation reaction is discharged from the sulfidation reaction vessel 1, supplied to the reaction end solution storage tank 2, and temporarily stored. The reaction final liquid storage tank 2 is an airtight container. The nickel / cobalt mixed sulfide 15 precipitated in the reaction final liquid storage tank 2 and the nickel poor liquid 16 as the supernatant liquid are separately separated and discharged.

In the sulfurization reaction vessel 1, in order to recover nickel and cobalt as sulfides in a high yield, a sulfurizing agent is added in excess of the required theoretical equivalent. Unreacted hydrogen sulfide gas in the sulfidation reaction is discharged from the sulfidation reaction vessel 1. For this reason, the exhaust gas 17 discharged from the sulfurization reactor 1 contains hydrogen sulfide gas.

The exhaust gas 17 (including hydrogen sulfide gas) discharged from the sulfurization reaction vessel 1 is detoxified by the first gas cleaning tower 3 and then discharged out of the system as a detoxified exhaust gas 18. In the first gas cleaning tower 3, a sodium hydroxide aqueous solution 19 is used as an absorbing liquid, and the hydrogen sulfide gas in the exhaust gas 17 is absorbed by the sodium hydroxide aqueous solution 19.

As shown in the following chemical formula 4, when hydrogen sulfide gas is absorbed in the sodium hydroxide aqueous solution, hydrogen sulfide (H ₂ S) and sodium hydroxide (NaOH) react to form an aqueous solution containing sodium hydrosulfide (NaSH). Generated. Thereby, the hydrogen sulfide gas which is a toxic gas is removed.
(Chemical formula 4)
H ₂ S + NaOH → NaSH + H ₂ O

The concentration and supply amount of the sodium hydroxide aqueous solution 19 are adjusted so that the removal of the hydrogen sulfide gas contained in the exhaust gas 17 is sufficiently achieved. For example, when an aqueous sodium hydroxide solution having a concentration of 15 to 25% by mass is used, an aqueous solution containing sodium hydrosulfide having a concentration of 20 to 35% by mass can be obtained.

The absorbing liquid 19 circulates inside the first gas cleaning tower 3, and the hydrogen sulfide gas in the exhaust gas 17 is absorbed. Moreover, the new absorption liquid 19 is supplied to the 1st gas washing tower 3, and the absorption liquid 20 in which the hydrogen sulfide gas was absorbed instead is discharged | emitted. The absorbent 20 contains the produced sodium hydrosulfide and unreacted sodium hydroxide. The absorption liquid 20 (sodium hydroxide aqueous solution containing sodium hydrosulfide) discharged from the first gas cleaning tower 3 is supplied to the second gas cleaning tower 4 as an absorption liquid.

Hydrogen sulfide is dissolved in the reaction end solution 14 stored in the reaction end solution storage tank 2. This hydrogen sulfide is discharged from the sulfurization reaction vessel 1 and part of the hydrogen sulfide is discharged as the temperature and pressure drop. For this reason, the exhaust gas 21 discharged from the reaction final liquid storage tank 2 contains hydrogen sulfide gas. Note that the amount of hydrogen sulfide gas discharged from the reaction final solution storage tank 2 is smaller than the amount of hydrogen sulfide gas discharged from the sulfurization reaction vessel 1. Therefore, the hydrogen sulfide concentration of the exhaust gas 21 discharged from the reaction final solution storage tank 2 is lower than the hydrogen sulfide concentration of the exhaust gas 17 discharged from the sulfurization reaction vessel 1.

The exhaust gas 21 (including hydrogen sulfide gas) discharged from the reaction final solution storage tank 2 is detoxified by the second gas cleaning tower 4 and then discharged out of the system as a detoxified exhaust gas 22. In the second gas cleaning tower 4, the absorbing liquid 20 (sodium hydroxide aqueous solution containing sodium hydrosulfide) discharged from the first gas cleaning tower 3 is used as the absorbing liquid, and the hydrogen sulfide gas in the exhaust gas 21 is absorbed. 20 to absorb. Reaction of hydrogen sulfide with sodium hydroxide produces sodium hydrosulfide. Here, unreacted sodium hydroxide remaining in the absorbent 20 contributes to the reaction. Thereby, the hydrogen sulfide gas which is a toxic gas is removed.

The absorbing liquid 20 circulates inside the second gas cleaning tower 4 and the hydrogen sulfide gas in the exhaust gas 21 is absorbed. In addition, the absorbing liquid 20 is supplied to the second gas cleaning tower 4, and the absorbing liquid 23 in which hydrogen sulfide gas is absorbed is discharged instead. The absorbing liquid 23 (aqueous solution containing sodium hydrosulfide) discharged from the second gas cleaning tower 4 is supplied to the sodium hydrosulfide storage tank 5.

In the sodium hydrosulfide storage tank 5, the absorbing solution 23 discharged from the second gas cleaning tower 4, that is, the aqueous solution 13 containing sodium hydrosulfide is temporarily stored. The sodium hydrosulfide storage tank 5 and the sulfurization reaction vessel 1 are connected by a pipe 6, and a pump 7 is provided in the pipe 6. Therefore, the aqueous solution 13 containing sodium hydrosulfide stored in the sodium hydrosulfide storage tank 5 can be supplied to the sulfurization reaction vessel 1 by driving the pump 7. That is, the aqueous solution 13 containing sodium hydrosulfide is temporarily stored and then supplied to the reaction starter 11.

In addition, the sodium hydrosulfide storage tank 5, the pipe 6, and the pump 7 correspond to the “circulator” described in the claims. The circulation device is not particularly limited as long as the absorbing solution 23 discharged from the second gas cleaning tower 4 can be supplied to the sulfurization reaction vessel 1 as an aqueous solution 13 containing sodium hydrosulfide. Moreover, it is good also as a structure which is not equipped with the sodium hydrosulfide storage tank 5. FIG.

As described above, by the first gas cleaning tower 3 and the second gas cleaning tower 4, the absorption liquid 19 made of the sodium hydroxide aqueous solution is changed from the unreacted hydrogen sulfide gas 17 in the sulfidation reaction and the reaction end liquid 14 of the sulfidation reaction. The discharged hydrogen sulfide gas 21 is absorbed to obtain an aqueous solution 13 containing sodium hydrosulfide. Then, the obtained aqueous solution 13 containing sodium hydrosulfide is supplied to the reaction start solution 11.

In this way, in addition to the unreacted hydrogen sulfide gas 17 in the sulfurization reaction, the hydrogen sulfide gas 21 discharged from the reaction final solution 14 is also absorbed by the aqueous sodium hydroxide solution 19 to generate sodium hydrosulfide to produce a sulfurization reaction vessel. Since it repeats to 1,

hydrogen sulfide gas

17 and 21 can be used effectively. As a result, the supply amount of sodium hydrosulfide 13 to the sulfurization reaction vessel 1 increases, so that the hydrogen sulfide reaction efficiency can be improved.

Further, since the aqueous solution 13 containing sodium hydrosulfide is temporarily stored in the sodium hydrosulfide storage tank 5, the amount of the aqueous solution 13 containing sodium hydrosulfide generated by the first gas cleaning tower 3 and the second gas cleaning tower 4 is determined to be a sulfurization reaction vessel. When the amount is larger than the amount supplied to 1 (reaction starting solution 11), the surplus can be stored. On the other hand, when the amount of the aqueous solution 13 containing sodium hydrosulfide generated by the first gas cleaning tower 3 and the second gas cleaning tower 4 is smaller than the supply amount to the sulfurization reaction vessel 1 (reaction starting liquid 11), temporary storage is performed. The aqueous solution 13 containing sodium hydrosulfide can be supplied to the sulfurization reaction vessel 1 (reaction starting solution 11). As a result, the total amount of sodium hydrosulfide that had to be partially discarded in the prior art can be repeated in the sulfurization reaction vessel 1 (reaction start solution 11), and the supply amount of sodium hydrosulfide increases. Therefore, the hydrogen sulfide reaction efficiency can be improved also by this effect.

Furthermore, since the absorbing liquid 20 obtained from the first gas cleaning tower 3 is used in the second gas cleaning tower 4, the amount of sodium hydroxide aqueous solution 19 used can be reduced. That is, since the unreacted sodium hydroxide remaining in the absorbent 20 without being used for removing hydrogen sulfide gas in the first gas cleaning tower 3 can be effectively used in the second gas cleaning tower 4, The amount of sodium hydroxide required for recovery as sodium hydrosulfide can be reduced, and the basic unit of sodium hydroxide can be reduced. As a result, the operating cost can be suppressed.

Next, examples will be described.
Example 1
The nickel / cobalt mixed sulfide was recovered using the production facility A shown in FIG. In addition, the sulfurization reaction container 1 connected 4 units | sets in series, and performed the sulfurization reaction continuously. The reaction starting liquid 11 is a mother liquid for nickel recovery (a sulfuric acid aqueous solution containing nickel and cobalt), and has a nickel concentration of 4.2 to 4.5 g / L and a cobalt concentration of 0.26 to 0.34 g / L. The nickel load on the sulfurization reactor 1 is 1.9 to 2.2 kg / hour / m ³ . The pH, nickel recovery rate, hydrogen sulfide reaction efficiency, and sodium hydroxide basic unit of the nickel poor solution obtained in this operation were evaluated.

(Comparative Example 2)
The nickel / cobalt mixed sulfide was recovered using the production facility B shown in FIG. The production facility B has a configuration in which the aqueous solution 13 containing sodium hydrosulfide discharged from the first gas cleaning tower 3 in the production facility A is directly repeated in the sulfurization reaction vessel 1. Of the aqueous solution 13 containing sodium hydrosulfide discharged from the first gas cleaning tower 3, the surplus portion 20 is discharged to the wastewater treatment process outside the system. A new sodium hydroxide aqueous solution 19 is supplied to the second gas cleaning tower 4, and the aqueous solution 23 containing sodium hydrosulfide discharged from the second gas cleaning tower 4 is discharged to a wastewater treatment process outside the system.

Sulfurization reaction vessel 1 was connected in series with 4 units to continuously perform a sulfidation reaction. The reaction starting liquid 11 is a mother liquid for nickel recovery (a sulfuric acid aqueous solution containing nickel and cobalt), and has a nickel concentration of 4.2 to 4.5 g / L and a cobalt concentration of 0.27 to 0.37 g / L. The nickel load on the sulfurization reactor 1 is 1.9 to 2.2 kg / hour / m ³ . The pH, nickel recovery rate, hydrogen sulfide reaction efficiency, and sodium hydroxide basic unit of the nickel poor solution obtained in this operation were evaluated.

The evaluation results of Example 1 and Comparative Example 1 are shown in FIGS. FIG. 4 is a graph showing the relationship between the sodium hydrosulfide addition ratio and the nickel poor solution pH, FIG. 5 is a graph showing the relationship between the sodium hydrosulfide addition ratio and the nickel recovery rate, and FIG. 6 is the sodium hydrosulfide addition ratio and hydrogen sulfide. FIG. 7 is a graph showing the relationship between reaction efficiency and sodium hydrosulfide addition ratio and sodium hydroxide basic unit.

Here, the sodium hydrosulfide addition ratio is defined by the following formula 1.
(Equation 1)
A = V _NaSH ÷ V _S
Here, A is the sodium hydrosulfide addition ratio, V _NaSH is the volume of the aqueous sodium hydrosulfide solution, and V _S is the volume of the reaction starting solution.

The nickel recovery rate as nickel sulfide and cobalt sulfide in the sulfurization reaction is defined by the following formula 2.
(Equation 2)
R = (V _S × ρ _S-Ni −V _B × ρ _B-Ni ) ÷ (V _S × ρ _S-Ni )
Where R is the nickel recovery rate, V _S is the volume of the reaction start solution, ρ _S-Ni is the nickel concentration of the reaction start solution, V _B is the volume of the nickel poor solution, and ρ _B-Ni is the nickel concentration of the nickel poor solution. It is.

The hydrogen sulfide reaction efficiency is defined by the following formula 3.
(Equation 3)
E = ((V _S × ρ _S-Ni −V _B × ρ _B-Ni ) ÷ Ar (Ni) + (V _S × ρ _S-Co −V _B × ρ _B-Co ) ÷ Ar (Co)) ÷ (V _H2S ÷ 22.4)
Where E is the hydrogen sulfide reaction efficiency, V _S is the volume of the reaction start solution, ρ _S-Ni is the nickel concentration of the reaction start solution, ρ _S-Co is the cobalt concentration of the reaction start solution, and V _B is the nickel poor solution Volume, ρ _B-Ni is the nickel concentration of the nickel poor solution, ρ _B-Co is the cobalt concentration of the nickel poor solution, Ar (Ni) is the nickel atomic weight, Ar (Co) is the cobalt atomic weight, and V _H2S is the volume of hydrogen sulfide used It is.

The sodium hydroxide basic unit is defined by the following formula 4.
(Equation 4)
U = W _NaOH ÷ W _Ni
Here, U is the sodium hydroxide basic unit, W _NaOH is the amount of sodium hydroxide used in the first gas cleaning tower 3 and the second gas cleaning tower 4, and W _Ni is the amount of nickel obtained as a sulfide.

As can be seen from FIG. 4, the sodium hydrosulfide addition ratio is 0.50% on average in Example 1, whereas it is 0.37% on average in Comparative Example 1. That is, in Example 1, the sodium hydrosulfide addition ratio is about 1.35 times that of Comparative Example 1. From this, according to Example 1, it was confirmed that the supply amount of sodium hydrosulfide to the sulfurization reaction vessel 1 increases.

Also, it can be seen that Example 1 has an average pH of 0.15 higher than that of Comparative Example 2. Thereby, according to Example 1, when the supply amount of the sodium hydrosulfide to the sulfurization reaction container 1 increased, it was confirmed that the fall of pH by a sulfurization reaction can be suppressed.

As can be seen from FIG. 5, the nickel recovery rate of Example 1 is 98.2% on average, and the nickel recovery rate of Comparative Example 1 is 98.1% on average, and an equivalent nickel recovery rate is obtained.

On the other hand, as can be seen from FIG. 6, the average hydrogen sulfide reaction efficiency of Example 1 is 93.7%, while the average hydrogen sulfide reaction efficiency of Comparative Example 1 is 89.9%. High efficiency. Thus, according to Example 1, the amount of hydrogen sulfide used was reduced while maintaining a high nickel recovery rate of 97.5% or more in the sulfidation reaction by increasing the amount of sodium hydrosulfide supplied to the sulfidation reaction vessel 1 It was confirmed that it was possible.

As can be seen from FIG. 7, the sodium hydroxide basic unit of Example 1 averaged 0.25 (NaOH-t / Ni-t), whereas the sodium hydroxide basic unit of Comparative Example 1 averaged 0.29 (NaOH— t / Ni-t). From this, according to Example 1, since the unreacted sodium hydroxide in the 1st gas washing tower 3 is used in the 2nd gas washing tower 4, the usage-amount of sodium hydroxide can be reduced, and sodium hydroxide basic unit can be reduced. It was confirmed that it can be reduced.

A Production equipment 1 Sulfurization reaction vessel 2 Reaction final solution storage tank 3 First gas cleaning tower 4 Second gas cleaning tower 5 Sodium hydrosulfide storage tank 6 Piping 7 Pump 11 Reaction start liquid 12 Hydrogen sulfide gas 13 Aqueous solution containing sodium hydrosulfide 14 Reaction final solution 15 Nickel / cobalt mixed sulfide 16 Nickel poor solution 17 Exhaust gas 18 Detoxified exhaust gas 19 Absorbing solution (sodium hydroxide aqueous solution)
20 Absorbing liquid 21 Exhaust gas 22 Exhausted exhaust gas 23 Absorbing liquid

Claims

An aqueous sulfuric acid solution containing a valuable metal as a reaction start liquid, an aqueous solution containing hydrogen sulfide gas and sodium hydrosulfide as a sulfiding agent, and a sulfide reaction vessel for producing a valuable metal sulfide by a sulfidation reaction;
A reaction end solution storage tank to which a reaction end solution discharged from the sulfurization reaction vessel is supplied;
A first gas scrubbing tower for absorbing hydrogen sulfide gas discharged from the sulfurization reaction vessel into an absorbing solution composed of a sodium hydroxide aqueous solution;
A second gas cleaning tower for absorbing the hydrogen sulfide gas discharged from the reaction final liquid storage tank into the absorption liquid discharged from the first gas cleaning tower;
And a circulation device for supplying the absorption liquid discharged from the second gas cleaning tower to the sulfurization reaction vessel as an aqueous solution containing the sodium hydrosulfide.
2. The sulfide production facility according to claim 1, wherein the circulation device includes a sodium hydrosulfide storage tank that temporarily stores an aqueous solution containing the sodium hydrosulfide discharged from the second gas cleaning tower.
3. The sulfide according to claim 1, wherein the reaction initial solution is a nickel recovery mother liquor obtained by removing impurities from a leachate obtained by leaching a slurry containing nickel oxide ore with sulfuric acid. Manufacturing equipment.
Supplying an aqueous solution containing hydrogen sulfide gas and sodium hydrosulfide as a sulfiding agent to a sulfuric acid aqueous solution containing a valuable metal as a reaction starting liquid, a sulfide of a valuable metal is generated by a sulfidation reaction,
An aqueous solution containing sodium hydrosulfide is obtained by absorbing unreacted hydrogen sulfide gas in the sulfidation reaction and hydrogen sulfide gas discharged from the reaction final solution of the sulfidation reaction in an absorption solution comprising an aqueous sodium hydroxide solution,
A method for producing a sulfide, wherein the obtained aqueous solution containing sodium hydrosulfide is supplied to the reaction starting solution.
The method for producing a sulfide according to claim 4, wherein the aqueous solution containing sodium hydrosulfide is temporarily stored and then supplied to the reaction start solution.
6. The sulfide according to claim 4 or 5, wherein the reaction starting liquid is a mother liquid for nickel recovery obtained by removing impurities from a leachate obtained by leaching a slurry containing nickel oxide ore with sulfuric acid. Manufacturing method.