JPH0258330B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for removing copper ions from a nickel-containing chloride solution. [Prior art] Electric nickel is produced by melting and casting nickel pine and electrolytically refining it using this as an anode.
This is done by leaching out the nickel content in nickel pine using an oxidizing agent such as chlorine, preparing an electrolytic solution from the obtained leaching solution, and performing electrowinning. In these methods, the copper contained in the nickel pine is mixed with the nickel in an electrolyte,
Or it leaches into the exudate. When performing electrolysis using a leachate, if the leachate is electrolyzed as is, copper ions will be deposited on the cathode during electrolysis, increasing the concentration of copper as an impurity in the electrodeposited nickel. Concentration is 0.001g/
A step is provided to remove copper until it becomes less than 100%. US Pat. No. 2,180,520 describes a method of using nickel pine to remove copper ions from a nickel chloride solution obtained by leaching nickel pine with chlorine. This method uses the metal nickel in the nickel mat,
Although this method precipitates copper ions in the elongation solution as metallic copper, it is not possible to remove the copper concentration in the solution to less than 0.001g/. In addition, Japanese Patent Publication No. 56-24021 discloses that copper ions in the leachate obtained by leaching nickel pine with chlorine are combined with elemental sulfur and nickel sulfide with a molar ratio of Ni/S>1. A method for removing it is described. This method uses a combination of nickel sulfide and elemental sulfur to remove copper ions in the liquid as sulfide, and requires a reaction temperature of 100°C or higher, which requires expensive equipment. Therefore, even if a large amount of nickel pine is used, the copper ion concentration in the solution after decoppering will only decrease to about 0.013g/, and in order to supply it as an electrolyte to the cathode of the electrolytic cell, further solvent extraction is required. There is a problem in that copper removal processes such as copper removal processes must be performed. Furthermore, the residue after reacting copper ions in the liquid with nickel pine contains several tens of weight percent of nickel, and it is necessary to recover this nickel by chlorine leaching. Elemental sulfur is leached according to the reaction shown in equation (1), producing SO ₄ ^2- and increasing the SO ₄ ^2- concentration in the leachate.
An increase in the SO ₄ ^2- concentration increases the ratio of the side reaction of oxygen generation shown in equation (2) during electrowinning of nickel, and significantly reduces the generation of chlorine gas that should be used for leaching chlorine from nickel pine. However, there is a problem in that it deteriorates the ruthenium-titanium composite electrode used as an inert anode. S+3Cl ₂ +4H ₂ O=SO ₄ ^2- +6Cl ^- +8H (1) 2H ₂ O=O ₂ +4H ⁺ +4e ^- (2) [Problem to be solved by the invention] The present invention solves the problem of reaction at 100°C or higher, which was conventionally required. temperature,
It is possible to lower the copper ion concentration in the final solution to less than 0.001 g/l so that it can be used as is for electrowinning, and it is possible to lower the temperature to 70°C or less, which allows the use of inexpensive equipment materials. Another object of the present invention is to provide a method for removing copper ions from a chloride solution in which the residue generated by copper removal treatment can be leached with chlorine. [Means for Solving the Problems] The means for solving the problems according to the present invention is to add nickel pine with a particle size of 100 μm or less to a nickel chloride solution containing copper, and add nickel pine to the copper in the chloride solution in the nickel pine. of nickel in an amount that is at least 3 times the molar ratio, and the temperature of the chloride solution is increased to 40
A first step of maintaining the temperature at ~70°C and stirring for 30 minutes or more;
Nickel pine with a particle size of 100 μm or less is added to the solution that has undergone the first step, and the total amount of Ni ₃ S ₂ and metal Ni in the nickel pine is added to CuCl ₃ ^{2 -} all of the Cu ₂ S in the solution.
Copper in the solution is added in an amount that is at least 10 times the theoretical reaction amount to the amount of copper in the solution of nickel pine required to convert it into A method for removing copper ions from a chloride solution, which comprises adding an amount of 20 mol or more per 1 mol, and stirring the solution for 70 minutes or more while maintaining the temperature of the solution at 70°C or less. . [Effect] Regarding the first step, (a) Nickel pine particle size Ni200g/, Cu30g/, 270g/ at 60℃
Add 200 g of nickel pine of various particle sizes with the composition shown in Table 2 to chloride aqueous solution 1 with the composition of 0.5
After that time, take a portion as an analysis sample, stop stirring after 2 hours, separate the solid and liquid, measure the copper concentration in the separated solution, and determine the particle size of the nickel pine and the copper concentration in the separated solution. The relationship between this and the copper removal rate was determined. The results are shown in Table 1.

【table】

[Table] From the results in Table 1, it can be seen that the copper removal rate decreases when the particle size of the nickel pine added is less than 100 μm. (b) Addition amount of nickel pine To aqueous solution 1 with a composition of Ni200g/, Cu20g/, Cl270g/, a second particle with a particle size of 100 μm or less is added.
Varying amounts of nickel pine having the composition shown in the table were added, stirred at 60°C for 2 hours, solid-liquid separated, and the copper concentration in the resulting liquid was measured. The results are shown in Table 3.

[Table] From the results in Table 3, the amount of nickel pine added is such that if the amount of nickel in the nickel pine added is less than 3 mol per 1 mol of copper in the solution, the copper concentration in the final solution will not become small. I understand. (c) Reaction temperature A second solution with a particle size of 100 μm or less is added to an aqueous solution 1 with a composition of Ni200g/, Cu20g/, Cl270g/.
Add 160g of nickel pine with the composition shown in the table,
Stir for 2 hours while changing the reaction temperature, separate solid and liquid,
The copper concentration in the obtained liquid was measured. The results are shown in Table 4.

[Table] From the results in Table 4, it can be seen that the reaction temperature is preferably 40 to 70°C. The reason for this is thought to be as follows. In general, nickel pine contains metallic Ni in addition to Ni ₃ S ₂ , and if elemental sulfur is not present, the reactions shown by the following equations (3), (4), and (5) will occur. Equations (3) and (4) are the dissolution reactions of Ni ₃ S ₂ and metal Ni, respectively, and are paired with the electrochemical precipitation reaction of copper ions shown in equation (5). It is. Ni ⁰ = Ni ² +2e ^- (3) Ni ₃ S ₂ = Ni ²⁺ +2NiS+2e ^- (4) Cu ²⁺ +2e ^- = Cu ⁰ (5) In addition, in the case of a chloride solution as in the present invention,
The precipitation reaction of metallic copper from the monovalent copper chloro complex shown in equation (6) is considered, but the deposition potential of copper from this monovalent copper chloro complex is 300 mV higher than the copper precipitation potential in equation (5). Since the above values are also low, it is considered unlikely to occur under normal conditions. CuCl ₃ ^2- +e ^- = Cu ⁰ +3Cl ^- (6) The higher the reaction temperature, the more the reactions in equations (3) and (4) progress, and the copper ions in the liquid precipitate as metallic copper. However, on the other hand, due to the dissolved oxygen in the liquid and the air drawn in by stirring, the re-dissolution of metallic copper proceeds according to the reverse reaction of the reaction shown in equation (6), and as a result, the copper removal rate decreases. it is conceivable that. On the other hand, when the reaction temperature drops below 40℃,
The reactions of equations (3), (4), and (5) and the redissolution of metallic copper will become less likely to occur, and as a result, the copper removal rate will decrease, but in any case, the temperature dependence of each reaction is It is thought that a complex combination results in an optimum temperature range between 40 and 70°C. (d) Reaction time To aqueous solution 1 with a composition of Ni200g/, Cu30g/, Cl270g/, a second particle with a particle size of 100 μm or less is added.
Add 200g of nickel pine with the composition shown in the table,
The mixture was stirred at a reaction temperature of 50° C. while varying the reaction time, solid-liquid separation was performed, and the copper concentration in the resulting liquid was measured. The results are shown in Table 5.

[Table] In order to minimize the amount of elemental sulfur used in the second step, which is the next step, it is necessary to reduce the copper ions in the liquid after the first step to around 0.1g/. is desirable. In order to achieve this purpose, 30
It turns out that it is better to react for more than a minute. Regarding the second step, (a) Particle size of nickel pine Ni200g/, Cu0.08g/, Cl270g/
Into aqueous solution 1 with the composition, 4 g of nickel pine with the composition shown in Table 2 with various particle sizes and 100 μm particle size.
Add the following 2.3g of sulfur, and at a reaction temperature of 20℃
The mixture was stirred for a period of time, separated into solid and liquid, and the copper concentration in the resulting liquid was measured. The results are shown in Table 6.

[Table] In order to use the copper-removed solution after completing this second step as an electrolyte for nickel, the copper concentration in the solution must be less than 0.001g/, as shown in Table 6. From this, it can be seen that it is sufficient to use nickel pine with a particle size of 100 μm or less. (b) Addition amount of nickel pine Ni200g/, Cu0.08g/, Cl270g/
In aqueous solution 1 with the composition of, particles with a particle size of 100 μm or less
Various amounts of nickel pine with a composition of Ni83.3, Cu0.2, Fe0.5, S14.0 each weight% and sulfur with a particle size of 100 μm or less were added in an amount twice the amount of nickel pine, and the reaction temperature was 20℃. The mixture was stirred for a period of time, solid-liquid separated, and the copper concentration in the resulting liquid was measured. The results are shown in Table 7.

[Table] *...Molar ratio of sulfur added to 1 mole of copper in the stock solution Also, the ratio to the theoretical reaction amount of nickel pine can be obtained from the following equations (7) and (8) as follows. 3Ni ₃ S ₂ +S ⁰ +2CiCl ₃ ^2- =3Ni ²⁺ +6Cl ^- +6NiS+Cu ₂ S (7) 3Ni ⁰ +S ⁰ +2CuCl ₃ ^2- =3Ni ₂ ⁺ +6Cl ^- +Cu ₂ S (8) Mat grade Ni83.3% S14. 0% Cu0.2% Fe0.5% Ni83.3÷58.71 = 1.418 mole S14.0÷32.06 = 0.436 mole Cu0.2÷63.54 = 0.003 mole Fe0.5÷55.85 = 0.009 mole FeS → 0.009 mole CuS → 0.003 mol Ni ₃ S ₂ → (0.436 − 0.009 − 0.003) ÷ 2 = 0.212 mol Ni ⁰ → 1.418 − 0.212 × 3 = 0.782 mol ∴ FeS 0.009 × 87.91 = 0.8% CuS 0.003 × 95.61 = 0.3% Ni ₃ S ₂ 0.212×240.25=51.0% Ni ⁰ 0.782×58. 71=45.9% +98% From formula (7), Ni ₃ S ₂ :CiCl ₃ ^2- = 3:2 Ni ₃ S ₂ in 100g of this nickel pine
The molar amount of CiCl ₃ ^2- that can convert CiCl ₃ ^2- to Cu ₂ S is 0.212 mol x 2/3 = 0.141 mol (8), Ni ⁰ :CiCl ₃ ^2- = 3:2 in 100 g of this nickel pine. Ni ₀ and CiCl ₃ ^2-
The molar amount of CuCl ₃ ^2- that can be converted into Ci ₂ S is CuCl ₃ ^2- = 0.782 mol x 2/3 = 0.521 mol The total amount of Ni ₃ S ₂ and Ni ⁰ in 100 g of this nickel pine is CiCl ₃ ^{2 -} can be converted to Cu ₂ S CuCl ₃ ^2-
The molar amount of is 0.141 + 0.521 = 0.662 mol CuCl ₃ ^2- in 100 g of this nickel pine,
The weight percent of Cu that can be converted into Cu ₂ S and removed is 0.662×63.54=42.06g. Therefore, the weight percentage of Cu in liquid 1 containing 0.08g/Cu is 0.662×63.54=42.06g.
The theoretical reaction amount of this nickel pine required to convert all of CuCl ₃ ^2- into Cu ₂ S with respect to the amount of copper in this solution is 100:42.06=x:0.08 x=0.19g in Table 7. Multiplying ratio for the theoretical reaction amount of nickel pine 0.33 ÷ 0.19 = 1.73 times 1.66 ÷ 0.19 = 8.73 times 2.00 ÷ 0.19 = 10.52 times 3.00 ÷ 0.19 = 15.78 times From Table 7, the copper concentration in the copper-removed final solution is kept as it is in the electrolyte. In order to make it less than 0.001g/ that can be used as
The total amount of Ni ₃ S ₂ and Ni ⁰ can convert CiCl ₃ ^2- into Cu ₂ S. Add 10 times or more of nickel pine to the reaction theoretical amount based on the amount of copper in the initial solution of nickel pine. It turns out it's necessary. In this case, the theoretical reaction amount of nickel pine with respect to the amount of copper is calculated, but if the amount is calculated with respect to CuCl ₃ ^2- or Cu ₂ S, the numerical value will be different, but the actual amount will be the same. Since they are the same, they belong to the scope of the present invention. (c) Sulfur particle size Ni200g/, Cu0.08g/, Cl270g/
In aqueous solution 1 with the composition of, particles with a particle size of 100 μm or less are
4g of nickel pine with the composition shown in Table 2 and particle size
2.3 g of sulfur of various proportions of 100 μm or less were added, stirred at a reaction temperature of 20° C. for 2 hours, solid-liquid separated, and the copper concentration in the resulting liquid was measured. 8th result
Shown in the table.

[Table] From the results shown in Table 8, it can be seen that sulfur containing many particles with a particle size exceeding 100 μm has poor copper removal efficiency. Using sulfur containing many particles with a particle size of over 100 μm, the copper concentration in the copper-removed final solution was reduced to <0.001.
g/g/g/g/g/g, it is necessary to add a large amount of sulfur, resulting in an increase in the amount of sulfur in the generated residue. Therefore, the particle size of the sulfur used must be 90% by weight or more of 100 μm or less. (d) Amount of sulfur added Ni200g/, Cu0.08g/, Cl270g/
In aqueous solution 1 with the composition of, particles with a particle size of 100 μm or less are
4g of nickel pine with the composition shown in Table 2 and particle size
Various amounts of sulfur of 100 μm or less were added, stirred at a reaction temperature of 60° C. for 2 hours, solid-liquid separated, and the copper concentration in the resulting liquid was measured. The results are shown in Table 9.

[Table] The S/Cu molar ratio is the ratio of the molar amount of copper in the stock solution to the molar amount of sulfur added. From the results in Table 9, the copper concentration in the copper-removed final solution is <
It can be seen that in order to obtain 0.001 g/mol, it is necessary to add sulfur in an amount of 20 moles or more per mole of copper in the stock solution. (e) Reaction temperature Ni200g/, Cu0.08g/, Cl270g/
Into aqueous solution 1 with the composition of
2.6 g of sulfur with 90% by weight or more of 100 μm or less was added, stirred for 2 hours at various reaction temperatures, solid-liquid separated, and the copper concentration in the resulting liquid was measured. The results are shown in Table 10.

[Table] From the results in Table 10, in the second step, the reaction temperature was
It can be seen that by keeping the temperature below 70°C, the copper concentration in the liquid can be reduced to below 0.001g/. (f) Reaction time Ni200g/, Cu0.08g/, Cl270g/
Into aqueous solution 1 with the composition of
2.6 g of sulfur with 90% by weight or more of 100 μm or less was added, stirred at a reaction temperature of 40° C. for various reaction times, solid-liquid separation, and the copper concentration in the resulting liquid was measured. The results are shown in Table 11.

〔Example〕

Cementation tank No. 1 for the first process, which has an actual capacity of 100 mm and is equipped with an agitator, a heating coil, and an overflow pipe; Cementation No. 2 for the second process, equipped with a cooling pipe and a extraction nozzle
An apparatus consisting of a tank, a metering pump connected to the extraction nozzle of tank No. 2, and a filter press for separating solid and liquid from the slurry extracted from the metering pump was used. In the cementation No. 1 tank, Ni 160g/,
A chloride solution with a composition of 19 g of Cu/208 g of Cl was supplied for 48 h/hr, and 6.0 Kg/hr of nickel pine with a composition shown in Table 2, the total amount of which was 100 μm or less in particle size and 90% by weight of which was 75 μm or less in particle size. Incubate at 45℃ for 45 minutes and remove cementation from the overflow tube.
It overflowed into No. 2 tank. For cementation No. 2, the above nickel pine is used at 0.25Kg/hr.
And, the particle size is 100μm or less, and more than 90% by weight is 45μm in size.
2 at 40℃ with the addition of 0.165Kg/hr of sulfur.
Allowed time to react. From cementation tank No. 2,
Using a metering pump, the solution was taken out to a filter press at a rate of 48 l/hr and subjected to solid-liquid separation to obtain a copper-free final solution. The copper concentration in the solution from cementation tank No. 1 to No. 2 tank is 0.087 g/, and the copper concentration in the final copper-free solution is
It was 0.0005g/. Ni/Cu molar ratio in the first step = 5.56, magnification of the theoretical reaction amount of nickel pine in the second step =
18.9, and the S/Cu molar ratio was 78.3. In this way, the second step can be performed without solid-liquid separation in the first step. In addition, in the generated residue
The ^S0 grade was 2.6% by weight. [Effects of the Invention] According to the method of the present invention, the copper concentration in the copper-containing chloride solution can be reduced to 0.001 g/or less, so the electrolyte can be directly poured into the nickel electrolytic cell without having to undergo copper removal treatment again. Can be used as Furthermore, in the method of the present invention, the amount of sulfur added is smaller than that of the conventional method, so the amount of sulfur in the final residue is small, and chlorine leaching of nickel in the residue can be carried out efficiently.

Claims (1)

[Claims] 1 Particle size 100μ in a nickel chloride solution containing copper.
m or less of nickel pine is added in such an amount that the amount of nickel in the nickel pine is at least three times the molar ratio of the copper in the chloride solution, and the temperature of the chloride solution is maintained at 40 to 70°C. A first step of stirring for 30 minutes or more, and adding nickel pine with a particle size of 100 μm or less to the solution after the first step.
The total amount of Ni ₃ S ₂ and metal Ni in the solution is CuCl ₃ ^2-
10 of the theoretical reaction amount for the amount of copper in the solution of nickel pine required to convert all of the copper into Cu ₂ S.
The amount is more than double, and more than 90% by weight has a particle size of 100 μm.
Sulfur consisting of the following is added in an amount of 20 moles or more per 1 mole of copper in the solution, and the temperature of the solution is raised to 70 °C.
A method for removing copper ions from a chloride solution, comprising: a second step of maintaining the temperature at or below °C and stirring for 70 minutes or more.