Method for preferentially removing calcium ions in nickel-cobalt solution without saponification

Abstract

The invention relates to a method for preferentially removing calcium ions in a nickel-cobalt solution without saponification, which comprises the following steps of: extracting the nickel-cobalt solution from which iron and aluminum are removed by using an unsaponified extracting agent P204 to obtain raffinate and a P204 loaded organic phase; the P204 loaded organic phase is sequentially subjected to washing, reverse extraction, anti-iron and water washing, and an organic phase is obtained; and the obtained organic phase is not saponified and is reused for extraction. When the method provided by the invention is used for extraction, the extraction agent P204 does not need to be saponified, so that the consumption of alkali is reduced; moreover, P204 is not saponified, so that the pH value of extraction balance can be reduced, co-extraction of Ni and Co is reduced, and the loss of Ni and Co is reduced; according to the method, on the premise that the extraction agent P204 is not saponified, the concentration of acid used for washing can be reduced, so that calcium sulfate crystals are prevented from being generated in a washing section, and an extraction tank is prevented from being blocked.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrometallurgy, and relates to a method for removing impurity calcium ions, in particular to a method for preferentially removing calcium ions in a nickel-cobalt solution without saponification. Background Art

[0002] With the rapid development of electric vehicles, the research and production of ternary battery materials have also been improved by leaps and bounds, and the demand for high-purity nickel and cobalt metals has increased significantly. To meet the demand for ternary battery materials, the extraction and purification technologies of nickel and cobalt have been vigorously developed.

[0003] The existing process for purifying negative electrode nickel and cobalt from a sulfuric acid solution rich in nickel and cobalt includes: first removing iron by the goethite method, and then extracting and removing impurities and back-extracting with P204. During the process of extracting and removing impurities with P204, it is necessary to wash the P204 organic phase after extraction. Since the control of F in the wastewater is relatively strict, NaF cannot be used to remove saturated Ca before the P204 extraction and impurity removal. - As a result, more Ca will be introduced into the extraction process and enter the P204 organic phase. During the washing stage in the process of extracting and removing impurities with P204, the back-washed Ca combines with SO4 2+ to precipitate at the bottom of the extraction tank in the form of calcium sulfate precipitate. As time goes by, more and more calcium sulfate crystals will form, resulting in the blockage of the stirring paddle, the weir opening of the extraction tank, the pipe orifice, and the clarification chamber by calcium sulfate crystals, which requires a large amount of manpower for cleaning and shoveling, affecting the extraction efficiency. 2+ 2+ 2-

[0004] CN112760482A discloses a method for reducing calcium sulfate deposition during the P204 extraction and impurity removal process, washing the P204 loaded organic phase after extraction, and the washing includes primary washing and secondary washing; water and hydrochloric acid are added to the P204 loaded organic phase during both the primary washing process and the secondary washing process; during the primary washing process, the flow rate of water is V1, and the flow rate of hydrochloric acid is V2; during the secondary washing process, the flow rate of water is V1 ` and the flow rate of hydrochloric acid is V2 ` ; wherein, V1:V2=(8-12):1, V1 ` :V2 ` =(4-6):1. However, before the P204 extraction and impurity removal, it is necessary to saponify P204 with sodium hydroxide, and then extract the leaching solution containing nickel sulfate or cobalt sulfate to obtain the P204 loaded organic phase. Due to the saponification, the alkali consumption is increased, and Ni and Co are co-extracted, increasing the loss of Ni and Co.

[0005] For this, a method for preferentially removing calcium ions from nickel-cobalt solution without saponification is required. Summary of the Invention

[0006] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a method for preferentially removing calcium ions from nickel-cobalt solution without saponification, which can reduce the consumption of alkali, reduce the loss of Ni and Co, and can also avoid the generation of calcium sulfate crystals in the washing section.

[0007] To achieve the purpose of this invention, the following technical solutions are adopted:

[0008] The present invention provides a method for preferentially removing calcium ions from nickel-cobalt solution without saponification, and the method includes the following steps:

[0009] Use the unsaponified extractant P204 to extract the nickel-cobalt solution after iron and aluminum removal to obtain a raffinate and a P204-loaded organic phase;

[0010] The P204-loaded organic phase is successively washed, stripped, de-ironed, and water-washed to obtain an organic phase; the obtained organic phase is not saponified and is recycled for extraction.

[0011] When the method provided by the present invention is used for extraction, it is not necessary to saponify the extractant P204, which reduces the consumption of alkali; moreover, the non-saponification of P204 can reduce the extraction equilibrium pH value, reduce the co-extraction of Ni and Co, and reduce the loss of Ni and Co; on the premise of not saponifying the extractant P204, the method can reduce the concentration of the acid used for washing, thereby avoiding the generation of calcium sulfate crystals in the washing section and avoiding clogging of the extraction tank.

[0012] Preferably, the pH value of the nickel-cobalt solution after iron and aluminum removal is 4 - 5.

[0013] Preferably, in the nickel-cobalt solution after iron and aluminum removal, the content of Co is 10 g / L - 13.5 g / L, the content of Ni is 25.5 g / L - 27 g / L, and the content of Ca is 525 mg / L - 565 mg / L.

[0014] Preferably, the concentration of the extractant P204 is 24 vol% - 27 vol%.

[0015] Preferably, the O / A volume ratio of the extraction is 0.5:1 - 2:1.

[0016] Preferably, the O / A volume ratio of the washing is 5:1 - 10:1.

[0017] Preferably, the washing is carried out using hydrochloric acid and / or sulfuric acid.

[0018] Preferably, the concentration of hydrochloric acid used for washing is 0.1 mol / L - 1 mol / L.

[0019] Preferably, the concentration of sulfuric acid used for washing is 0.075 mol / L - 1 mol / L.

[0020] Preferably, the O / A volume ratio for stripping is 5:1 - 10:1.

[0021] Preferably, the stripping is carried out using hydrochloric acid.

[0022] Preferably, the concentration of hydrochloric acid used for stripping is 1 mol / L - 4 mol / L.

[0023] Preferably, the O / A volume ratio for iron back-extraction is 5:1 - 20:1.

[0024] Preferably, the iron back-extraction is carried out using hydrochloric acid with a concentration of 5.8 mol / L - 6.2 mol / L.

[0025] Preferably, the O / A volume ratio for water washing is 5:1 - 20:1.

[0026] As a preferred technical solution of the method provided by the present invention, the method includes the following steps:

[0027] (1) Using the unsaponified extractant P204 to extract the nickel-cobalt solution after iron and aluminum removal with a pH value of 4 - 5, obtaining a raffinate and a P204-loaded organic phase;

[0028] In the nickel-cobalt solution after iron and aluminum removal, the content of Co is 10 g / L - 13.5 g / L, the content of Ni is 25.5 g / L - 27 g / L, and the content of Ca is 525 mg / L - 565 mg / L;

[0029] The concentration of the extractant P204 is 24 vol% - 27 vol%;

[0030] The O / A volume ratio for extraction is 0.5:1 - 2:1;

[0031] (2) The P204-loaded organic phase is successively washed with an O / A volume ratio of 5:1 - 10:1, stripped with an O / A volume ratio of 5:1 - 10:1, iron back-extracted with an O / A volume ratio of 5:1 - 20:1, and water washed with an O / A volume ratio of 5:1 - 20:1 to obtain an organic phase; the obtained organic phase is not saponified and recycled for extraction;

[0032] The washing is carried out using hydrochloric acid with a concentration of 0.1 mol / L - 1 mol / L and / or sulfuric acid with a concentration of 0.075 mol / L - 1 mol / L;

[0033] The stripping is carried out using hydrochloric acid with a concentration of 1 mol / L - 4 mol / L;

[0034] The iron removal is carried out using hydrochloric acid with a concentration of 5.8 mol / L - 6.2 mol / L.

[0035] The numerical ranges described in the present invention include not only the point values exemplified above, but also any point values between the above numerical ranges not exemplified. Due to space limitations and for the sake of brevity, the specific point values included in the described ranges are not exhaustively listed in the present invention.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] When the method provided by the present invention is used for extraction, it is not necessary to saponify the extractant P204, reducing the consumption of alkali; moreover, without saponification of P204, the extraction equilibrium pH value can be reduced, reducing the co-extraction of Ni and Co and reducing the loss of Ni and Co; on the premise of not saponifying the extractant P204, the method can reduce the concentration of acid used for washing, thereby avoiding the generation of calcium sulfate crystals in the washing section and avoiding clogging of the extraction tank. Specific Embodiments

[0038] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the described embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0039] An embodiment of the present invention provides a method for preferentially removing calcium ions from a nickel-cobalt solution without saponification, the method comprising the following steps:

[0040] Using the unsaponified extractant P204 to extract the nickel-cobalt solution after iron and aluminum removal to obtain a raffinate and a P204-loaded organic phase;

[0041] The P204-loaded organic phase is successively washed, stripped, de-ironed and water-washed to obtain an organic phase; the obtained organic phase is not saponified and recycled for extraction.

[0042] When the method provided by the present invention is used for extraction, it is not necessary to saponify the extractant P204, reducing the consumption of alkali; moreover, without saponification of P204, the extraction equilibrium pH value can be reduced, reducing the co-extraction of Ni and Co and reducing the loss of Ni and Co; on the premise of not saponifying the extractant P204, the method can reduce the concentration of acid used for washing, thereby avoiding the generation of calcium sulfate crystals in the washing section and avoiding clogging of the extraction tank.

[0043] The nickel-cobalt solution after iron and aluminum removal in the present invention is obtained by reducing leaching of waste ternary battery powder with sulfuric acid reducing agent and removing iron and aluminum with calcium hydroxide.

[0044] In some embodiments, the pH value of the nickel-cobalt solution after iron and aluminum removal is 4 - 5. For example, it can be 4, 4.2, 4.5, 4.8, or 5, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0045] The treatment object of the present invention is the nickel-cobalt solution after iron and aluminum removal, whose initial pH value is 4 - 5. There is no need to adjust the pH value for extraction, reducing the consumption of acid.

[0046] In some embodiments, in the nickel-cobalt solution after iron and aluminum removal, the content of Co is 10 g / L - 13.5 g / L, the content of Ni is 25.5 g / L - 27 g / L, and the content of Ca is 525 mg / L - 565 mg / L.

[0047] Among them, the content of Co is 10 g / L - 13.5 g / L. For example, it can be 10 mg / L, 10.5 mg / L, 11 mg / L, 11.5 mg / L, 12 mg / L, 12.5 mg / L, 13 mg / L, or 13.5 mg / L, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0048] The content of Ni is 25.5 g / L - 27 g / L. For example, it can be 25.5 mg / L, 26 mg / L, 26.5 mg / L, or 27 mg / L, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0049] The content of Ca is 525 mg / L - 565 mg / L. For example, it can be 525 mg / L, 530 mg / L, 535 mg / L, 540 mg / L, 545 mg / L, 550 mg / L, 555 mg / L, 560 mg / L, or 565 mg / L, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0050] In some embodiments, the concentration of the extractant P204 is 24 vol% - 27 vol%. For example, it can be 24 vol%, 24.5 vol%, 25 vol%, 25.5 vol%, 26 vol%, 26.5 vol%, or 27 vol%, but is not limited to the listed values. Other unlisted values within the numerical range are equally applicable.

[0051] The concentration of the extractant P204 in the present invention is adjusted by a diluent, and the diluent includes but is not limited to kerosene.

[0052] In some embodiments, the O / A volume ratio of extraction is 0.5:1 - 2:1. For example, it can be 0.5:1, 1:1, 1.5:1, or 2:1, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.

[0053] In some embodiments, the O / A volume ratio of washing is 5:1 - 10:1. For example, it can be 5:1, 6:1, 8:1, 9:1, or 10:1, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.

[0054] In some embodiments, the washing is carried out using hydrochloric acid and / or sulfuric acid.

[0055] In some embodiments, the concentration of hydrochloric acid used for washing is 0.1 mol / L - 1 mol / L. For example, it can be 0.1 mol / L, 0.3 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, or 1 mol / L, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.

[0056] In some embodiments, the concentration of sulfuric acid used for washing is 0.075 mol / L - 1 mol / L. For example, it can be 0.075 mol / L, 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.8 mol / L, or 1 mol / L, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable, and preferably it is 0.15 mol / L - 1 mol / L.

[0057] The method provided by the present invention uses low - concentration hydrochloric acid and sulfuric acid during washing, which can avoid the generation of calcium sulfate crystals during washing, thereby effectively avoiding the blockage of the extraction tank.

[0058] In some embodiments, the O / A volume ratio of back - extraction is 5:1 - 10:1. For example, it can be 5:1, 6:1, 8:1, 9:1, or 10:1, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.

[0059] In some embodiments, the back - extraction is carried out using hydrochloric acid.

[0060] In some embodiments, the concentration of hydrochloric acid used for back - extraction is 1 mol / L - 4 mol / L. For example, it can be 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, 3.5 mol / L, or 4 mol / L, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.

[0061] In some embodiments, the O / A volume ratio of the anti-iron is 5:1 - 20:1. For example, it can be 5:1, 8:1, 10:1, 12:1, 15:1, 18:1 or 20:1, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.

[0062] In some embodiments, the anti-iron is carried out using hydrochloric acid with a concentration of 5.8 mol / L - 6.2 mol / L. For example, it can be 5.8 mol / L, 5.9 mol / L, 6 mol / L, 6.1 mol / L or 6.2 mol / L, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.

[0063] In some embodiments, the O / A volume ratio of the water washing is 5:1 - 20:1. For example, it can be 5:1, 8:1, 10:1, 12:1, 15:1, 18:1 or 20:1, but is not limited to the listed values. The other unlisted values within the numerical range are equally applicable.

[0064] The O / A volume ratio in the present invention refers to the volume ratio of the organic phase to the aqueous phase.

[0065] As a preferred technical solution of the method provided by the present invention, the method comprises the following steps:

[0066] (1) Using the unsaponified extractant P204 to extract the nickel-cobalt solution after iron and aluminum removal with a pH value of 4 - 5, to obtain a raffinate and a P204-loaded organic phase;

[0067] In the nickel-cobalt solution after iron and aluminum removal, the content of Co is 10 g / L - 13.5 g / L, the content of Ni is 25.5 g / L - 27 g / L, and the content of Ca is 525 mg / L - 565 mg / L;

[0068] The concentration of the extractant P204 is 24 vol% - 27 vol%;

[0069] The O / A volume ratio of the extraction is 0.5:1 - 2:1;

[0070] (2) The P204-loaded organic phase is successively washed with an O / A volume ratio of 5:1 - 10:1, stripped with an O / A volume ratio of 5:1 - 10:1, de-ironed with an O / A volume ratio of 5:1 - 20:1, and washed with an O / A volume ratio of 5:1 - 20:1 to obtain an organic phase; the obtained organic phase is not saponified and is recycled for extraction;

[0071] The washing is carried out using hydrochloric acid with a concentration of 0.1 mol / L - 1 mol / L and / or sulfuric acid with a concentration of 0.075 mol / L - 1 mol / L;

[0072] The stripping is carried out using hydrochloric acid with a concentration of 1 mol / L - 4 mol / L;

[0073] The iron removal is carried out using hydrochloric acid with a concentration of 5.8 mol / L - 6.2 mol / L.

[0074] The concentration of the extractant P204 in the present invention is regulated by the diluent kerosene, and this will not be elaborated further in the following examples and comparative examples.

[0075] Example 1

[0076] This example provides a method for preferentially removing calcium ions from a nickel-cobalt solution without saponification, and the method includes:

[0077] (1) Using the unsaponified extractant P204 to extract the nickel-cobalt solution after iron and aluminum removal with a pH value of 5, obtaining a raffinate and a P204-loaded organic phase;

[0078] In the nickel-cobalt solution after iron and aluminum removal, the content of Co is 10.9 g / L, the content of Ni is 26.7 g / L, and the content of Ca is 525 mg / L;

[0079] In the raffinate, the content of Co is 10.5 g / L, the content of Ni is 25.7 g / L, and the content of Ca is 2 mg / L;

[0080] The concentration of the extractant P204 is 25 vol%;

[0081] The O / A volume ratio of the extraction is 1:1;

[0082] (2) The P204-loaded organic phase is successively washed with an O / A volume ratio of 10:1, stripped with an O / A volume ratio of 8:1, subjected to iron removal with an O / A volume ratio of 10:1, and washed with water with an O / A volume ratio of 10:1 to obtain an organic phase; the obtained organic phase is not saponified and is recycled for extraction;

[0083] The washing is carried out using hydrochloric acid with a concentration of 0.4 mol / L;

[0084] The stripping is carried out using hydrochloric acid with a concentration of 2 mol / L;

[0085] The iron removal is carried out using hydrochloric acid with a concentration of 6 mol / L.

[0086] During the extraction and washing in the method provided in this example, no calcium sulfate crystallization occurs.

[0087] Example 2

[0088] This embodiment provides a method for preferentially removing calcium ions from a nickel-cobalt solution without saponification. The method includes:

[0089] (1) Using the unsaponified extractant P204 to extract the iron- and aluminum-removed nickel-cobalt solution with a pH value of 4.27 to obtain a raffinate and a P204-loaded organic phase;

[0090] In the iron- and aluminum-removed nickel-cobalt solution, the content of Co is 13.36 g / L, the content of Ni is 27.8 g / L, and the content of Ca is 550.2 mg / L;

[0091] In the raffinate, the content of Co is 13.1 g / L, the content of Ni is 26.7 g / L, and the content of Ca is 3 mg / L;

[0092] The concentration of the extractant P204 is 25 vol%;

[0093] The O / A volume ratio of the extraction is 0.9:1;

[0094] (2) The P204-loaded organic phase is successively washed with an O / A volume ratio of 10:1, stripped with an O / A volume ratio of 8:1, deferred with an O / A volume ratio of 10:1, and washed with water with an O / A volume ratio of 10:1 to obtain an organic phase; the obtained organic phase is not saponified and recycled for extraction;

[0095] The washing is carried out using hydrochloric acid with a concentration of 1 mol / L;

[0096] The stripping is carried out using hydrochloric acid with a concentration of 4 mol / L;

[0097] The deferring is carried out using hydrochloric acid with a concentration of 6.2 mol / L.

[0098] In the extraction and washing of the method provided in this embodiment, no calcium sulfate crystallization occurs.

[0099] Example 3

[0100] This embodiment provides a method for preferentially removing calcium ions from a nickel-cobalt solution without saponification. The method includes:

[0101] (1) Using the unsaponified extractant P204 to extract the iron- and aluminum-removed nickel-cobalt solution with a pH value of 4.5 to obtain a raffinate and a P204-loaded organic phase;

[0102] In the iron- and aluminum-removed nickel-cobalt solution, the content of Co is 12.2 g / L, the content of Ni is 25.8 g / L, and the content of Ca is 563.5 mg / L;

[0103] The content of Co in the raffinate is 12 g / L, the content of Ni is 24.6 g / L, and the content of Ca is 11.6 mg / L;

[0104] The concentration of the extractant P204 is 25 vol%;

[0105] The O / A volume ratio of the extraction is 0.75:1;

[0106] (2) The P204-loaded organic phase is successively washed with an O / A volume ratio of 10:1, stripped with an O / A volume ratio of 8:1, deferred with an O / A volume ratio of 10:1, and washed with water with an O / A volume ratio of 10:1 to obtain an organic phase; the obtained organic phase is not saponified and is recycled for extraction;

[0107] The washing is carried out using hydrochloric acid with a concentration of 1 mol / L;

[0108] The stripping is carried out using hydrochloric acid with a concentration of 4 mol / L;

[0109] The deferring is carried out using hydrochloric acid with a concentration of 5.8 mol / L.

[0110] During the extraction and washing of the method provided in this example, no calcium sulfate crystallization occurs.

[0111] Example 4

[0112] This example provides a method for preferentially removing calcium ions from a nickel-cobalt solution without saponification, and the method includes:

[0113] (1) Using the unsaponified extractant P204 to extract the iron- and aluminum-removed nickel-cobalt solution with a pH value of 5 to obtain a raffinate and a P204-loaded organic phase;

[0114] In the iron- and aluminum-removed nickel-cobalt solution, the content of Co is 10.9 g / L, the content of Ni is 26.7 g / L, and the content of Ca is 525 mg / L;

[0115] The content of Co in the raffinate is 10.7 g / L, the content of Ni is 26.3 g / L, and the content of Ca is 18.5 mg / L;

[0116] The concentration of the extractant P204 is 24 vol%;

[0117] The O / A volume ratio of the extraction is 0.5:1;

[0118] (2) The P204-loaded organic phase is successively washed with an O / A volume ratio of 5:1, stripped with an O / A volume ratio of 5:1, deferred with an O / A volume ratio of 5:1, and washed with water with an O / A volume ratio of 5:1 to obtain an organic phase; the obtained organic phase is not saponified and is recycled for extraction;

[0119] The washing is carried out with hydrochloric acid at a concentration of 0.1 mol / L;

[0120] The stripping is carried out with hydrochloric acid at a concentration of 1 mol / L;

[0121] The iron stripping is carried out with hydrochloric acid at a concentration of 6 mol / L.

[0122] In the extraction and washing of the method provided in this example, no calcium sulfate crystallization occurs.

[0123] Example 5

[0124] This example provides a method for preferentially removing calcium ions from a nickel-cobalt solution without saponification, and the method includes:

[0125] (1) Using the unsaponified extractant P204 to extract the nickel-cobalt solution after iron and aluminum removal with a pH value of 5, obtaining a raffinate and a P204-loaded organic phase;

[0126] In the nickel-cobalt solution after iron and aluminum removal, the content of Co is 10.9 g / L, the content of Ni is 26.7 g / L, and the content of Ca is 525 mg / L;

[0127] In the raffinate, the content of Co is 9.9 g / L, the content of Ni is 24.6 g / L, and the content of Ca is 0.1 mg / L;

[0128] The concentration of the extractant P204 is 27 vol%;

[0129] The O / A volume ratio of the extraction is 2:1;

[0130] (2) The P204-loaded organic phase is successively washed with an O / A volume ratio of 10:1, stripped with an O / A volume ratio of 10:1, iron-stripped with an O / A volume ratio of 20:1, and washed with water with an O / A volume ratio of 20:1 to obtain an organic phase; the obtained organic phase is not saponified and is recycled for extraction;

[0131] The washing is carried out with hydrochloric acid at a concentration of 1 mol / L;

[0132] The stripping is carried out with hydrochloric acid at a concentration of 4 mol / L;

[0133] The iron stripping is carried out with hydrochloric acid at a concentration of 6 mol / L.

[0134] In the extraction and washing of the method provided in this example, no calcium sulfate crystallization occurs.

[0135] Example 6

[0136] This example provides a method for preferentially removing calcium ions from nickel-cobalt solution without saponification. Except for using sulfuric acid with a concentration of 0.15 mol / L during washing, the rest is the same as in Example 1.

[0137] During extraction and washing of the method provided in this example, no calcium sulfate crystals are produced.

[0138] Example 7

[0139] This example provides a method for preferentially removing calcium ions from nickel-cobalt solution without saponification. Except for using sulfuric acid with a concentration of 0.5 mol / L during washing, the rest is the same as in Example 1.

[0140] During extraction and washing of the method provided in this example, no calcium sulfate crystals are produced.

[0141] Example 8

[0142] This example provides a method for preferentially removing calcium ions from nickel-cobalt solution without saponification. Except for using sulfuric acid with a concentration of 1 mol / L during washing, the rest is the same as in Example 1.

[0143] During extraction and washing of the method provided in this example, no calcium sulfate crystals are produced.

[0144] Comparative Example 1

[0145] This comparative example provides a method for removing calcium ions from nickel-cobalt solution. Except for using an extractant P204 with a saponification rate of 60% as the extractant, the rest is the same as in Example 1.

[0146] During washing of the method provided in this comparative example, no calcium sulfate crystals are produced.

[0147] Performance Characterization

[0148] For the methods provided in the above examples and comparative examples, the recovery rates of nickel and cobalt (the percentages of nickel and cobalt in the raffinate to nickel and cobalt in the nickel-cobalt solution) and the removal rate of calcium are calculated, and the obtained results are shown in Table 1.

[0149] Table 1

[0150]

[0151]

[0152] In summary, the method provided by the present invention preferentially removes calcium from the nickel-cobalt solution through the extractant P204, so that the Ca content in the raffinate is less than 5 mg / L. The use of a specific concentration of acid during washing can avoid the generation of calcium sulfate crystals, reduce the probability of pipeline blockage, equipment scaling and other problems, and improve production efficiency; moreover, the extractant P204 does not need to be saponified, which reduces the use of a large amount of liquid alkali and reduces costs; P204 is not saponified, which can reduce the extraction equilibrium pH value, reduce the co-extraction of Ni and Co, and reduce the loss of Ni and Co, wherein the loss of Ni does not exceed 5%, and the loss of Co does not exceed 2%.

[0153] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preferentially removing calcium ions from a nickel-cobalt solution without saponification, characterized in that, The method comprises the following steps: Using the unsaponified extractant P204 to extract the nickel-cobalt solution after iron and aluminum removal to obtain a raffinate and a P204-loaded organic phase; The P204-loaded organic phase is successively washed, stripped, deferred, and water-washed to obtain an organic phase; the obtained organic phase is not saponified and recycled for extraction.

2. The method according to claim 1, wherein The pH value of the nickel-cobalt solution after iron and aluminum removal is 4 - 5.

3. The method according to claim 1 or 2, characterized in that In the nickel-cobalt solution after iron and aluminum removal, the content of Co is 10 g / L - 13.5 g / L, the content of Ni is 25.5 g / L - 27 g / L, and the content of Ca is 525 mg / L - 565 mg / L.

4. The method according to claim 1, characterized in that The concentration of the extractant P204 is 24 vol% - 27 vol%.

5. The method according to claim 1, wherein The O / A volume ratio of the extraction is 0.5:1 - 2:

1.

6. The method according to claim 1, wherein The O / A volume ratio of the washing is 5:1 - 10:1; and / or, the washing is carried out using hydrochloric acid and / or sulfuric acid; and / or, the concentration of the hydrochloric acid used for the washing is 0.1 mol / L - 1 mol / L; and / or, the concentration of the sulfuric acid used for the washing is 0.075 mol / L - 1 mol / L.

7. The method according to claim 1, wherein The O / A volume ratio of the stripping is 5:1 - 10:1; and / or, the stripping is carried out using hydrochloric acid; and / or, the concentration of the hydrochloric acid used for the stripping is 1 mol / L - 4 mol / L.

8. The method according to claim 1, wherein The O / A volume ratio of the deferring is 5:1 - 20:1; and / or, the deferring is carried out using hydrochloric acid with a concentration of 5.8 mol / L - 6.2 mol / L.

9. The method according to claim 1, characterized in that, The O / A volume ratio of the water-washing is 5:1 - 20:

1.

10. The method according to claim 1, characterized in that The method comprises the following steps: (1) Using the unsaponified extractant P204 to extract the nickel-cobalt solution after iron and aluminum removal with a pH value of 4 - 5 to obtain a raffinate and a P204-loaded organic phase; In the nickel-cobalt solution after iron and aluminum removal, the content of Co is 10 g / L - 13.5 g / L, the content of Ni is 25.5 g / L - 27 g / L, and the content of Ca is 525 mg / L - 565 mg / L; The concentration of the extractant P204 is 24 vol% - 27 vol%; The O / A volume ratio of the extraction is 0.5:1 - 2:1; (2) The P204-loaded organic phase is successively washed with an O / A volume ratio of 5:1 - 10:1, stripped with an O / A volume ratio of 5:1 - 10:1, deferred with an O / A volume ratio of 5:1 - 20:1, and water-washed with an O / A volume ratio of 5:1 - 20:1 to obtain an organic phase; the obtained organic phase is not saponified and recycled for extraction; The washing is carried out using hydrochloric acid with a concentration of 0.1 mol / L - 1 mol / L and / or sulfuric acid with a concentration of 0.075 mol / L - 1 mol / L; The stripping is carried out using hydrochloric acid with a concentration of 1 mol / L - 4 mol / L; The deferring is carried out using hydrochloric acid with a concentration of 5.8 mol / L - 6.2 mol / L.

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