SU1126374A1 - Method of obtaining nickel powder - Google Patents

Abstract

1. METHOD FOR PREPARING NICKEL POWDER by hydrogen deposition in an autoclave at elevated temperature and pressure, about a hl and h and the fact that, in order to increase the activity of the powder and reduce the cost of the process, precipitation is carried out from a water slurry of nickel carbonate with an additive sulfate ion in an amount equivalent to 0.05 mol of nickel per liter of pulp, and after precipitation an inhibitor with reducing properties is introduced into the pulp. 2. Method POP.1, distinguished by the fact that formic acid in the amount of 0.5-2 g (in terms of 100 may.%) Per 1 liter of pulp of nickel powder is used as an inhibitor.

Description

. . 1 The invention relates to powder metallurgy, in particular, to the production of active nickel powders used in copper cleaning of electrolysis solutions of nickel from electrolysis shops. A known method for producing nickel powder is the reduction of nickel oxide with hydrogen-containing gas in a fluidized bed at 560-600 ° C. Lj The disadvantage of this method is the particle size of the obtained nickel powder (particle size up to 1000 µm), which leads to an increased consumption of powder during the cementation process, significant (up to 12-15%) loss of nickel with cement copper. Disrupting the dispersion of the powder pushed in this way requires additional costs for electricity and grinding equipment. The closest in technical essence and the achieved result to the invention is the method of obtaining nickel powder by the method of hydrogen deposition in an autoclave at elevated temperature and pressure. Aqueous ammonia solutions of nickel and cobalt carbonates with a mixture of zinc, magnesium, and manganese are used as a raw material. The method provides for pretreatment of solutions to remove cobalt to a ratio in solution. Ni: Co 100-200, followed by boiling the solution to separate the bases of nickel and cobalt carbonates, which are reduced by hydrogen from the aqueous slurry at a higher temperature and pressure to obtain a nickel powder. The disadvantage of this method is that in order to obtain basic carbonates, additional energy costs and costs for equipment for ammonia distillation are needed. In addition, the compression material obtained by this sample has a highly developed surface and is easily oxidized by atmospheric oxygen, which reduces its activity and impairs its cementation properties. The aim of the invention is to improve the activity of the powder and reduce the cost of the process. The goal is achieved by agreeing to a method for producing a nickel porous by hydrogen deposition in an autoclave at elevated temperatures. Low pressure precipitated piggy suck from a wave of nickel carbonate pulp g with sulfate-C1) and in an amount equivalent to 0.05 mol of nickel per 1; i- pulp, and after the precipitation an inhibitor with reducing properties is introduced into the pulp . As an inhibitor, formic acid is used in the amount of 0.52 g (based on 100 May.%) Per 1 liter of nickel powder pulp. The amount of inhibitor is due to the fact that with the introduction of butyric acid less than 0.5 g / l into the pulp, the activity of nickel powder decreases due to its surface oxidation, greater than 2.0 g / l — partial dissolution of the nickel powder begins, which leads to a decrease in the yield of metallic nickel The introduction of sulfuric acid or nickel sulfate in the process in an amount equivalent to less than 0.05 mol of nickel per 1 liter of pulp slows down the reduction process by 1.5 times; in the amount ,, equivalent to more than 6.05. A nickel mole accelerates the process, but at the same time nickel losses increase due to its soluble forms. The cost reduction of the process according to the proposed method as compared with the prototype is ensured by the fact that the preparation of nickel powder is carried out from aqueous slurries of basic nickel carbonate formed in the nickel carbonate autoclave during the withdrawal of the aggregate to the temperature reduction mode, i.e., to full energy costs and costs on additional equipment. . The predigam method was tested under laboratory conditions. The conditions of the experiments are as follows: temperature 180 ° C, total pressure in the autoclave 39 atm, partial pressure of hydrogen 30 atm, ratio g: t in a nickel carbonate pulp 5.0; composition of nickel carbonate, May. %: Nickel 36.0; copper1.01, 8; iron 0.08-0.1; sodium 4.5-5.0; fineness 100% class 100 microns. The results are tabulated. According to the proposed method, the process of obtaining nickel powder from an aqueous nicer-jr carbonate pulp with a weight ratio of g: t 5.0 is carried out in a laboratory autoclave with mechanical stirring (n 2800 rpm) with a capacity of 3 jifiTpa. Cooling the pulp of the obtained powder wire tv reducing atmosphere. After the pressure has been released, the inhibitor, formic acid, is introduced with the pulp under agitation. To ensure that the liver has a real process rate, sulfuric acid or nickel sulfate is added to the pulp in a quantity equivalent to 0.05 mol / l nickel. An increase in the additive, 07–0.08 mol / l for nickel (table, examples 3, 4) accelerates the process, but increases the loss of nickel with the solution. Reducing the amount of additive to 0.03 mol / l for nickel (example 5) leads to a 1.5-fold slowdown of the process. Transporting the resulting nickel powder without an inhibitor causes its oxidation, resulting in a powder with an activity of 18.8-29.0% (examples 1-5). The introduction of the inhibitor in the amount of 0.4 g / l is clearly not enough, since partial oxidation of the obtained powder takes place - 55% activity (example 6) ... Increasing the amount of inhibitor from 0.5 to 2 g / l (examples 7-8) retains powder activity at 75–82%. Further increase in inhibitor dose (Example 9T is impractical because the activity of the obtained powder does not increase, and the loss of nickel due to partial dissolution in excess acid increases. Thus, to obtain a nickel powder with an activity not lower than 75-82% by hydrogen reduction in autoclaves, it is necessary introduction of an inhibitor to the process in the amount of 0.5-2.0 g / l of nickel powder pulp. The use of the proposed method as compared with the known method makes it possible to obtain a fine powder with a higher activity as a result of which nickel losses are reduced by 1.52 times during copper cementation with this powder, the process of nickel powder production can be reduced by increasing the extraction of nickel carbonate nickel from 1.3 times, and also due to the fact that the feedstock to Nickel powder - nickel carbonate (nickel content 34 36.%) - is a waste obtained from hydrometallurgical processing of cobalt concentrates and recovered at the present time in the head of the metal melting sludge. The expected economic effect from the use of the proposed method is 757.9 thousand rubles. in year.

0.05

0.05 0.08

, 07

0.03 0.05

0.4 0.05 0.5

0.05

2.0 0.05 3.0

0.04

23.0

0.30 30.8 0.25 26.5 0.80 29.0 0.58 18.8 0.25 55.0 0.35 75.0 O, JSC

82.0

0.45 81.0 0.93

20.0

0.28

0.06 0.08

0.04. 0.06 0.07

0.03

Table continuation

23.0

0.75 28.0 0.78 19.5 0.25 21.5 0.74 29.0 0.60 18.8 0.25

Claims (2)

1. METHOD FOR PRODUCING NICKEL POWDER by hydrogen deposition in an autoclave at elevated temperature and pressure, I distinguish: in order to increase the activity of the powder and reduce the cost of the process, the deposition is carried out from an aqueous pulp of nickel carbonate with the addition of sulfate ion in an amount equivalent to 0.05 mol of nickel per 1 l of pulp, and after precipitation, an inhibitor with reducing properties is introduced into the pulp, 2. The method according to claim 1, with the fact that as an inhibitor, formic acid is used in an amount of 0.5-2 g (in terms of May 100.%) per 1 liter of nickel pulp powder.