RU2463254C1 - Method of producing nickel (ii) hydroxide - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention can be used in chemical industry. The method of producing nickel (II) hydroxide involves treatment of an acidic solution of nickel (II) sulphate in two steps, at the first step with ammonia water to pH 4-4.5, at the second step with sodium hydroxide to pH 11-12. At the second step, the process is carried out by feeding the suspension from the first step into the sodium hydroxide solution. Further, impurities are washed off from the residue in an ascending stream with variable hydrodynamic conditions. The residue is then pressed and dried.

EFFECT: invention increases purity of the product and uniformity of its grain-size distribution.

3 cl, 3 tbl, 3 ex

Description

The invention relates to the field of chemistry, namely the production of nickel (II) hydroxide, used mainly in the electrical industry.

A known method of producing Nickel (II) hydroxide for the active mass of the positive electrodes of alkaline batteries by pouring a solution of Nickel sulfate, heated to 80-90 ° C., In an alkali solution of the same temperature. The resulting suspension of Nickel hydroxide is filtered off, dried and, after grinding, washed from sodium sulfate and dried. The finished product is additionally boiled in a 16% alkali solution for one hour, after which it is washed with water and finally dried. The target product contains 56.2% nickel, 0.2% sulfate ion and provides a maximum capacity of at least 1.14 Ah / 3g Ni.

The method has the following disadvantages.

1. The stage of separation of the mother liquor from the precipitate is laborious, since the precipitate of nickel hydroxide has an amorphous structure and has a high resistivity during filtration.

2. Three times drying requires significant labor costs and increases energy consumption.

3. The need to process the finished product with an alkali solution lengthens the technological process and increases the consumption of sodium hydroxide (USSR, author certificate 51380 "Method for the treatment of nickel nitrate hydrate", IPC C01G 53/04, 12p, 4; 21v, 25, 1937).

There is also known a method for producing nickel (II) hydroxide, including its precipitation from pre-prepared stock solutions of sodium hydroxide and nickel (II) sulfate with the addition of barium ions as an activating additive. The resulting precipitate was separated by filtration, then dried, washed from sulfate ions, dried again and milled. This method has the following disadvantages.

1. The separation of the mother liquor from the amorphous precipitate of Nickel (II) hydroxide, which has a high resistivity during filtration, is laborious, is associated with a large investment of time and energy.

2. Double drying and the need for grinding also require large energy costs.

3. The introduction of barium at the stage of synthesis of nickel hydroxide does not lead to an improvement in the quality of the product, but complicates the process.

(MA Dasoyan, VV Novoderezhkin and others. "Production of electric batteries", M., "Higher School", 1977, 260-277.)

Another known method includes, after precipitation of nickel (II) hydroxide, as described above, the separation of the mother liquor, the extraction of the precipitate, drying to a certain humidity, washing from impurities and a second drying. After the first drying, a solution containing cobalt ions is introduced into the paste. After the first drying operation, a laboratory sample is taken from the batch of the semi-finished product and a quality forecast of the obtained batch of the product is carried out. If the laboratory sample does not meet the requirements of TU in specific volume, the resulting batch of product is treated with a 3% alkali solution in the ratio of 1 g of alkali to 10-15 g of nickel hydroxide and adjusted to the finished product.

The method has the following disadvantages.

1. High complexity, time and energy costs when separating the mother liquor from the amorphous precipitate of Nickel (II) hydroxide.

2. Large energy costs for double drying, grinding and classification of the final product.

3. The introduction of barium at the stage of synthesis of nickel hydroxide and impregnation of the precipitate after the first drying with a cobalt solution does not improve the quality of the target product, but complicate the process.

4. Activation of nickel hydroxide by the addition of barium and cobalt prevents the use of the product in other industries.

5. The introduction of operations to predict the quality and its adjustment increases the complexity of the process.

(Patent of the Russian Federation 2138447 "Method for the production of nickel (II) hydroxide", IPC 6 C01G 53/04, publ. 09/27/1999.)

The closest the claimed invention in technical essence is a method for producing nickel (II) hydroxide, including its precipitation by the interaction of an alkali metal hydroxide solution with a nickel (II) salt, washing the precipitate from impurities, its extraction and drying, characterized in that the precipitation of nickel hydroxide (II ) are introduced by the introduction of nickel (II) sulfate crystalline hydrate into a heated 15-30% alkali metal hydroxide solution; washing is carried out by treating the nickel hydroxide pulp in the column in countercurrent mode at an ascending linear velocity of a flow of 5-8 m / h with imposing pulsation perturbations in succession with an alkali solution and water, the pressed precipitate of nickel (II) hydroxide is sieved after drying.

In this case, nickel (II) hydroxide is precipitated with a solution of sodium hydroxide at 65-80 ° С at Т: Ж = 1: (4-7), the precipitate of nickel (II) hydroxide is washed from impurities with a 3-5% alkali solution at 45- 70 ° C. Drying of the target product is carried out in the microwave electromagnetic field (Patent of the Russian Federation 2208585 "Method for the production of nickel (II) hydroxide", IPC 6 C01G 53/04, publ. 07.20.2003).

As the disadvantages of the prototype, we note the need to use high purity nickel sulfate as a starting product and a wide range of fractional composition of crystalline nickel (II) hydroxide.

The claimed technical solution solves the problem of expanding the starting products for the production of nickel (II) hydroxide and to obtain a product of high purity with a more uniform particle size distribution.

The specified technical problem is achieved in that the method for producing nickel (II) hydroxide involves treatment with an alkaline solution, washing the precipitate from impurities in an upward flow with a variable hydrodynamic regime, extraction and drying, characterized in that the treatment of an acidic solution of nickel sulfate (P) is carried out in two stage, in the first ammonia water to a pH of 4-4.5, in the second sodium hydroxide to a pH of 11-12. In this case, in the second stage, the process is carried out by dosing a suspension of the first stage in a sodium hydroxide solution. In addition, the washing of nickel (II) hydroxide is carried out in an upward flow with a variable hydrodynamic regime at a linear velocity of the upward flow of 2-4.8 m / h, and drying is carried out in convective mode with the application of an electromagnetic field of a microwave frequency at a temperature of 105-115 ° С .

The essence of the proposed technical solution lies in the fact that nickel and ammonium double sulfate, a compound with a lower solubility in aqueous solutions than nickel sulfate, can be obtained from acidic sulfate solutions, which are waste products from electroplating plants, tail stock solutions of copper electrolyte plants and intermediate products recycling alkaline batteries. These solutions in the mode of their neutralization with ammonia water crystallize in the pH range 3-4.5. Subsequent neutralization of the solution leads to the precipitation of hydroxides of the relevant elements that are not included in the structure of the double salt and can be removed from the reaction zone by simply decanting the mother liquor or in the fractionation process in an upward flow. In this case, the resulting nickel hydroxide essentially repeats the granulometry of the double salt with a predominant content of fractions in the range of 20-30 microns. The essence of the proposed technical solution is confirmed by examples.

Example 1. Starting materials for the synthesis of nickel hydroxide: model sulfate nickel solutions containing 150 g / l NiSO ₄ and pH = 1.5, ammonia water 25%, sodium hydroxide. The reactor was filled with nickel sulfate and ammonia water was poured with constant stirring to pH 4.3. The resulting double salt is filtered off and washed in a pulsation column in countercurrent mode at a linear upward velocity of 6 m / h. In a reactor with a stirring device, an alkali solution with a pH of 11-12 is prepared and the double salt is sprinkled to the ratio T: W = 1: 6. The resulting suspension is sent for washing in the upper part of the pulsation column. Nickel hydroxide is washed in countercurrent mode with a linear ascending flow rate of 1-6 m / h. Shipment of the washed spherical nickel hydroxide is carried out through the bottom of the column. Washed spherical nickel hydroxide with T: W = 1: 3 is squeezed and dried in convective mode with the application of an electromagnetic field of the microwave frequency at a temperature of 105-115 ° C. Waste wash water is discharged through an overflow pipe at the top of the column and is collected in a sump. The finely dispersed part of the precipitate, which is nickel hydroxide, which does not correspond to TU in terms of particle size distribution in the amount of 4-12%, is captured in a sump. The performance of the Nickel hydroxide production process are shown in table 1.

Table 1 Nickel hydroxide washing mode selection Upstream speed, m / h Washing result one Does not meet the requirements of TU. The increased content of fine fractions and sulfate ions in the product. 2 Conforms to the requirements of TU. Direct yield 98%. The boundary content of the fine fraction and sulfate ions in the product. Low hardware performance. 3 Conforms to the requirements of TU. Direct product yield 97%. four Conforms to the requirements of TU. Direct product yield 96.5%. 5 Conforms to the requirements of TU. Direct yield of 94%. 6 Conforms to the requirements of TU. Direct yield 90%. Increased product entrainment.

Example 2. The starting materials for the synthesis of Nickel hydroxide: sulfate Nickel solutions, ammonia water 25% and sodium hydroxide. The reactor was filled with nickel sulfate and ammonia water was dosed with constant stirring to a pH of 2-5. The resulting pulp was incubated for 15 minutes with constant stirring. The double salt is separated from the solution by decantation. The process of deposition of Nickel hydroxide is carried out analogously to example 1. Washing the suspension is carried out analogously to example 1 at a linear velocity of upward flow of 4 m / h The indicators of the process for producing nickel hydroxide are presented in table 2.

table 2 Selection of the treatment regime with ammonia water The neutralization of Nickel sulfate solutions to pH Result 2.0 Conforms to the requirements of TU. Direct product yield 44%. 2.5 Conforms to the requirements of TU. Direct yield of 67%. 3.0 Conforms to the requirements of TU. Direct yield 88%. 3,5 Conforms to the requirements of TU. Direct yield of 92%. 4.0 Conforms to the requirements of TU. Direct product yield 95%. 4,5 Conforms to the requirements of TU. Direct yield 96%. 5,0 Conforms to the requirements of TU. Direct yield 96%.

Example 3. The starting materials for the synthesis of Nickel hydroxide: Nickel sulfate solutions, ammonia water 25% and sodium hydroxide. The reactor was filled with nickel sulfate and ammonia water was dosed with constant stirring to pH 4.5. The resulting pulp was incubated for 15 minutes with constant stirring. Sodium hydroxide solution is poured into the resulting double salt pulp to a pH of 5-9. The washing of the suspension is carried out analogously to example 1 at a linear velocity of upward flow of 4 m / h The indicators of the process for producing nickel hydroxide are presented in table 3.

Table 3 Selection of the treatment mode by alkali Treatment of pulp of double salt with sodium hydroxide solution to pH Result 5,0 Does not meet the requirements of TU. The increased content of sulfate ions. 5.5 Does not meet the requirements of TU. The increased content of sulfate ions. 6.0 Conforms to the requirements of TU. Direct yield 92% 6.5 Conforms to the requirements of TU. Direct yield of 94%. 7.0 Conforms to the requirements of TU. Direct yield 96%. 7.5 Conforms to the requirements of TU. Direct yield 96%. Increased alkali consumption. 8.0 Conforms to the requirements of TU. Direct yield 96%. Increased alkali consumption. 9.0 Conforms to the requirements of TU. Direct yield 96%. Increased alkali consumption.

Claims (3)

1. A method of producing nickel (II) hydroxide, including treatment with an alkaline solution, washing the precipitate from impurities in an ascending flow with a variable hydrodynamic regime, extraction and drying, characterized in that the treatment of an acidic solution of nickel (II) sulfate is carried out in two stages, in the first ammonia water to a pH of 4-4.5, on the second with sodium hydroxide to a pH of 11-12. 2. The method according to claim 1, characterized in that in the second stage the process is carried out by dosing a suspension of the first stage in a solution of sodium hydroxide. 3. The method according to claim 1, characterized in that the washing of Nickel (II) hydroxide is carried out in an upward flow with a variable hydrodynamic mode at a linear speed of the upward flow of 2-4.8 m / h, and drying is carried out in convective mode with the application of an electromagnetic field microwave frequency at a temperature of 105-115 ° C.