RU2287597C2 - Method of reprocessing of the oxygenated nickel-cobalt ores - Google Patents

Abstract

FIELD: nonferrous industry; methods of reprocessing of the oxygenated nickel-cobalt ores.

SUBSTANCE: the invention is pertaining to the field of metallurgy, in particular to the methods of extraction of nickel and cobalt from the ores and may be used at reprocessing of the oxygenated nickel and cobalt ores. The offered method provides, that the oxygenated ore is dried, ground and mixed in the granulator with the sulfuric acid, the gained granules first are sulfatized and then calcined in the operating in the counter-current mode tubular rotating furnace; from the calcined product by water leach nickel and cobalt; after separation from the cake, neutralization of the solution and settling of iron and aluminum, use sorption to produce nickel and cobalt and treat the saturated with the metals ionite to produce the nickel concentrate. Neutralization of the solution is conducted up to the value of Ph optimal for the ionite activity within the interval of its values from 3.0 up to 5.5 and then the sorption of nickel and cobalt from the gained mash is realized. The invention allows to achieve the high-degree extraction of the nickel and cobalt from the gained mash and the oxygenated ore with the low share of impurities and the waste metals.

EFFECT: the invention ensures achievement of the high-degree extraction of the nickel and cobalt from the gained mash as well as the oxygenated ore with the low share of impurities and the waste metals.

2 cl, 4 tbl, 4 ex

Description

The invention relates to methods for the extraction of nickel and cobalt from ores and can be used in the processing of oxidized nickel and cobalt ores.

There is a method of autoclave sulfuric acid leaching of nickel and cobalt from oxidized ores [1]. According to this method, for example, at the Moa Bay plant, pulp containing 45% of ore is heated with hot steam in heating columns, and then leached in a chain of four vapor lift autoclaves. Processing is carried out at a temperature of 240-250 ° C (pressure of about 4.0 MPa). The required sulfuric acid (98%) in an amount of about 240 kg / t of ore is fed into the first autoclave. Mixing in autoclaves is carried out with direct steam. Leaching time is 1-2 hours, while about 95% of nickel and cobalt passes into the solution. The disadvantages of the process: the high cost of equipment for autoclave leaching, the complexity of the operation of autoclaves.

Closest to the proposed technical solution is a method for the extraction of nickel and cobalt from laterite ores as a result of their mixing with sulfuric acid, heat treatment of the mixture and subsequent leaching of metals from the cinder [2]. According to this method, crushed ore up to -0.15 mm is pulped in water to obtain pulp with a content of about 60% solid material. Then the pulp is mixed for 15 minutes with a predetermined amount of concentrated sulfuric acid. The resulting paste is dried at a temperature above 110 ° C, the dried paste is crushed to a particle size of 4.7-1.65 mm, calcined at a temperature of up to 700-750 ° C, sulfates are leached from the calcine and precipitated from a solution of nickel and cobalt sulfides. Ore samples with a content of 1.20-2.27% nickel and 0.03-0.26% cobalt were tested. An extraction of 85% nickel and 90% cobalt was obtained. The disadvantages of the method are the difficulty of preparing a mixture of ore with sulfuric acid for calcination (pulp ore in water, drying an acid paste, crushing the dried paste with a significant yield of product of substandard size), two thermal operations (drying and calcination) and, accordingly, an increase in the number of equipment, relatively low extraction of Nickel from rich oxidized ores, use for the deposition of metals from solutions of leaching of toxic hydrogen sulfide.

The technical result of the proposed solution is to achieve a high degree of extraction of Nickel and cobalt from oxidized ore, including low metal content.

The technical result is achieved by the fact that according to the proposed method, the oxidized ore is dried, crushed and mixed in a granulator with sulfuric acid, the granules obtained are subsequently sulphated first and then calcined in a single stage in a counter-rotating tube rotary kiln, nickel is leached from the calcined product with water and cobalt, after neutralization of the solution and precipitation of iron and aluminum, nickel and cobalt are sorbed on the ion exchanger and the metal-saturated ion exchanger is processed to produce nickel cobalt th concentrate. The solution is neutralized to a pH optimum for ion exchange in the range of 3.0-5.5 and sorbed nickel and cobalt from the resulting pulp.

Example 1

Oxidized nickel ore with a nickel content of 0.70 and 1.25% was dried, crushed to a particle size of 100% -0.15 mm and mixed on a bowl granulator with sulfuric acid at a flow rate of 0.47-0.52 t / t ore. Successively, sulfatization and calcination operations were carried out by placing samples of the granulated mixture in a muffle furnace at room temperature and heating it to a predetermined value within 650-800 ° C. The heat treatment time is 4.5 hours. The calcined product was leached with water for 1 hour at a temperature of 70 ° C and T: W = 1: 1, the operation was repeated 3 times, after each solution was separated, after the last leaching, the granules were washed with water. The combined solution was analyzed. The data obtained are given in table 1.

Table 1 Effect of ore calcination temperature on metal recovery N p / p Contents Ni in ore,% Consumption of H ₂ SO ₄ (92%), t / t ore Temperature ° C The content in the solution, g / DM ³ Extracted from ore,% (Ni), kg / t ore Ni Fe Al Mg Ni Fe Al Mg one
2 0.70
1.25 0.54
0.53 20 → 650 1.15
3.02 6.55
10.9 1,2
2,5 4.6
5.9 79.9
88.8 31.8
40,2 5.8
9.2 22.4
21.8 3
four 0.70
1.25 0.57
0.51 20 → 700 1.80
3.35 6.97
19.9 1,6
3.2 5.9
6.4 99.6
99,2 27.0
73,4 6.2
11.8 22.8
23.8 5
6 0.70
1.25 0.54
0.56 20 → 750 1.98
3.35 4.26
7.8 1,6
2.2 8.1
6.0 93.3
98.0 12.9
29.1 4.8
8.4 24.5
22.6 7 1.25 0.65 20 → 800 3.15 2.0 1.7 8.1 75,2 6.1 5.1 24.3

As can be seen from table 1, with these processing parameters and maximum calcination temperatures of 700-750 ° C for the tested two samples, an equally high extraction of nickel in solution was achieved.

Example 2

Oxidized nickel ore with a content,%, 1.25 Ni; 0.44 Co; 17.9 Fe was mixed in a bowl granulator with sulfuric acid at a flow rate of 0.47 t / t ore. The obtained granules were processed in a tubular rotary kiln for 3.5 hours, and then leached with water at a ratio of T: W = 1: 1 three times for 1 hour, the solutions were combined and analyzed. The results of the experiments are shown in table.2.

table 2 Results of sequential leaching of granules Temperature ° C Recovery in solution,% Ni With Fe 600 86.4 95.2 27.4 650 95.2 93.0 23.8 700 92.0 95.3 6.4 750 2.2 4.6 0.1

In this example, the best results for the extraction of Nickel in the solution by leaching were obtained at a calcination temperature of 650 ° C. A further increase in temperature (up to 700 ° C) leads to a more complete decomposition of iron sulfate and, apparently, a partial screening of nickel compounds. As a result, there is a slight decrease in nickel recovery, however, a decrease in the amount of iron passing into the solution during leaching of nickel and cobalt plays a positive role in the subsequent purification of solutions of this metal.

Before sorption of nickel and cobalt from sulfuric acid solutions, the iron contained in the solution must be precipitated. To do this, you can neutralize the solution, for example, with limestone or calcium oxide. Experimental data show that the effectiveness of the indicated reagents has a significant difference (Table 3), which manifests itself in various degrees of coprecipitation with nickel iron (5.3 and 9.4%, respectively) and aluminum (96.4 and 99.5%) .

With an increase in pH above 3.5, the amount of metals passing into the precipitate increases both due to their coprecipitation with iron and due to the achievement of the pH of its own deposition. For example, when iron is precipitated from the initial solution shown in Table 3 by neutralizing it with calcium oxide to pH 5, the content in the iron solution decreases to 0.38; nickel - up to 1.38 (i.e. 18.8%); aluminum - up to 0.006 g / dm ³ .

Table 3 Precipitation of iron hydroxide. pH of the solutions after precipitation is 3.5-3.7 N p / p Solution Content, g / dm ³ Fe Ni Al Ca one Source 10.5 1.70 2.15 - 2 Precipitation of CaCO ₃ 1.95 1,61 0,077 0.41 3 CaO precipitation 1.18 1,54 0.011 0.43

The use of the process of sorption of these metals from the pulp allows minimizing the losses of nickel and cobalt with the iron precipitate, for which the pulp obtained after neutralization at constant pH and temperature is contacted with the ion exchanger in countercurrent mode. As ion exchangers, it is proposed to use pyridine hydroxyl ion exchangers, for example, HSV, or ion exchangers containing pyridinium nitrogen, for example, DOWEX XWS 4195 from DOW Chemical.

After sorption extraction of nickel and cobalt from the sulfate solution, the metal-saturated ion exchanger is washed with water and treated at 40-45 ° C with an aqueous solution of mineral acid (sulfuric, hydrochloric) with a concentration of not more than 3N. The resulting concentrated nickel-cobalt solutions are sent to precipitate carbonates or hydroxides.

Example 3

Sorption of nickel and cobalt from neutralized pulp with a pH of 5.0-5.5 was carried out with mechanical stirring, T: W = 1: 5, loading HSV in H ⁺ / SO ₄ ^2- - form 30% by volume of the pulp. The results are shown in table 4.

Thus, in the presence of ion exchanger recovery from pulp (liquid and solid phases) was 97.6% nickel and 99.2% cobalt.

Similar results on the recovery of nickel and cobalt from neutralized pulp were obtained using DOWEX XWS 4195 ion exchange resin from DOW Chemical. However, in this case, the process is carried out at a lower pH value of 3.0-3.5, which reduces the consumption of the neutralizer (CaCO ₃ ) by 10-12%.

The capacity of ion exchangers for nickel is, mg / g: HSV - 48.2; DOWEX XWS 4195 - 83.9.

Table 4 Metal sorption results Product Composition Processing stage product unit. element 0 * one 2 3 four 5 pulp, w. phase g / dm ³ Ni 8,625 3,880 1,120 0.354 0.009 0.0015 With 0.280 0.125 0,082 0.058 0.006 0,0004 pulp, tv phase % Ni 1,600 0.240 0.155 0,060 0,060 0.0290 With 0,050 0,020 0.010 <0.010 <0.010 <0.010 ion exchanger mg / g Ni - 61,4 48,2 45,2 32.6 30,4 With - 3.4 2,5 2.1 1,6 0.3 * source pulp

The treatment of ion exchangers saturated with nickel and cobalt with aqueous solutions of mineral acids, for example sulfuric, allows the metals to be concentrated in the form of a sulfate solution suitable for producing carbonate concentrate in a known manner. The completeness of the desorption of nickel and cobalt and the degree of their concentration depend on the acid concentration and the process temperature.

Example 4

A solution of sulfuric acid was treated with an ion exchanger saturated with nickel and cobalt under the conditions specified in example 3. The desorption of metals was carried out under dynamic conditions, the volume of commodity desorbate was 1.7-2.0 volume to the volume of ion exchanger.

The highest degree of desorption (99%) was achieved at a concentration of sulfuric acid in a stripping solution of 100-120 g / dm and a temperature of 40-45 ° C. The nickel concentration in the product desorbate was 8-10 g / dm ³ for HSV and 15-16 g / dm ³ for DOWEX XWS 4195.

Carbonate concentrate was precipitated from salable desorbates with a 15% solution of soda ash at a temperature of 70-80 ° С. The resulting concentrate was filtered, washed and dried. Based on the weight of the dry product, it contained,%: 38-45 Ni; 0.08-0.1 Co; 2.0-2.8 Fe; 1.0-1.1 Al; 0.4-0.5 Mg.

The technical efficiency of the proposed method for processing oxidized nickel ore is that as a result of using processes of mixing oxidized nickel ore with sulfuric acid on a granulator, solid-phase sulfatization of ore and calcining of granules, a good interaction of sulfuric acid and compounds of extracted valuable metals is ensured. Calcination of granules can drastically reduce the amount of iron passing into the solution during leaching. In turn, the sorption extraction of nickel and cobalt from pulps ensures the production of high-quality nickel-cobalt concentrate and minimizes the loss of these metals from the precipitation of iron hydroxide.

INFORMATION SOURCES

1. Reznik I.D., Ermakov G.P., Shneerson Y.M. Nickel. M.: Nauka i Tekhnologii LLC, 2001. Vol.2: Oxidized Nickel Ores, p. 3 85-3 88.

2. Zubryckyj N., Evans D.J.I., Mackiw V.N. Preferential sulfation of nikel and cobalt in lateritic ores // Journal of metals. 1965. May. P. 478-486.

Claims (2)

1. A method of processing oxidized nickel-cobalt ore, including drying and grinding the ore, treating the ore with sulfuric acid, heat treating the obtained product, transferring soluble sulfates to a solution and obtaining nickel-cobalt concentrate, characterized in that the ore is mixed with sulfuric acid using a granulator, the resulting granules are sulfated and then calcined in a tube rotary kiln operating in countercurrent mode, nickel and cobalt are leached from calcined granules with water and after neutralization the alignment and deposition of iron and aluminum ion exchanger to adsorb the nickel and cobalt metals and a saturated ion exchanger was treated to give nikelkobaltovogo concentrate. 2. The method according to claim 1, characterized in that the solution containing metal sulfates is neutralized to an optimum pH of ionite for operation in the range of 3.0-5.5 and nickel and cobalt are sorbed from the resulting pulp.