RU2458742C1 - Method of dressing oxide nickel ores - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to ore dressing and may be used for processing oxide nickel ore to up performances in pyrometallurgical production of ferroalloys. Proposed method comprises grinding ore to 2.0-3.0-mm-size, thermal treatment of ground ore to 550-600°C for, at least one hour, magnetic separation of annealed ore to extract magnetic fraction, fractionation of nonmagnetic fraction in its upward flow at hydrodynamic conditions and flow speed of 30-50 m/h to extract fraction of minus 0.3 mm.

EFFECT: power and material savings, simplified process.

Description

The invention relates to ore dressing and can be used to process oxidized nickel ores and improve technical and economic indicators in traditional pyrometallurgical methods for the production of ferroalloys.

Nickel in silicate ores is extremely dispersed. The crystal sizes of nickel-bearing minerals are small and usually do not exceed 10 microns [Vershinin A.S. Geology, prospecting and exploration of hypergenic nickel deposits. M .: Nedra, 1993, p. 304.]. Such a finely dispersed distribution of nickel in silicate ores makes it difficult to isolate intermediate products by nuclear-physical sorting and separation.

The second feature of silicate ores is the presence among the silicate ores of weathering products of relatively large precipitates in the form of dense masses of hydroxides of iron and silica - cuirass, ferruginous nodules, siliceous-ferrous aggregates with a high nickel content. Nodules and veins of opal, chalcedony, quartz, relic fragments of weakly weathered and silicified serpentinite have a low nickel content.

All oxidized ores for which metallurgical extraction methods are used, including pyrometallurgical methods, may be suitable for enrichment by this method. In fact, in these methods the ore is usually melted after reduction (if applicable) in electric furnaces in which nickel and some iron are in the form of an alloy, while other elements are removed into the glassy slag. These extraction methods consume huge amounts of energy, and the higher the nickel content in the ore, the less energy is required to produce a ton of nickel and the more metal is produced in the same installation. Therefore, the application of the method provides the possibility of either reducing the cost of metal production, or increasing the amount of metal produced on the same equipment.

There is a method of beneficiation of oxidized nickel-containing ores, carried out using a line including a device for pulping, a device for grinding in the process of washing the pulp ore, a heavy medium separator for separating granular (heavy) fractions that do not contain fine particles by density (gravity device), forming an enrichment module raw materials (see RF patent 2200632 C2, 03.20.2003, B03B 7/00), which is the closest analogue to the proposed invention and is taken as a prototype.

The disadvantages of the prototype is the complexity of the technology, the need for regeneration of heavy media and, as a result, high material costs.

An object of the invention is to simplify technology and reduce material costs.

The presented problem is solved in that the method of enrichment of oxidized nickel ores involves grinding and fractionation, characterized in that the source material is ground to a maximum particle size of 2.0-3.0 mm, the ground ore is subjected to heat treatment at a temperature of 550-600 ° C for at least one hour, a magnetic fraction is extracted from the calcined ore, and a non-magnetic fraction is sent for fractionation in an upward flow with a variable hydrodynamic mode at an upward flow velocity of 30-50 m / h to isolate the target fraction yc 0.3 mm.

The essence of the claimed technical solution lies in the fact that the heat treatment of oxidized nickel ores in the claimed modes leads to the manifestation of the detected effect - a sharp increase in the magnetic susceptibility of iron-containing phases in the composition of ore materials. At the same time, fragments of grains with increased magnetic susceptibility at least retain their strength, shape, and somewhat increased nickel content in their composition with respect to the total mass. The silicate base of oxidized ores during heat treatment loses strength characteristics, grain breakdown along cleavage boundaries and chipping of nickel enriched fragments from the total mass are observed. This nature of the observed changes makes it possible to realize additional opportunities for nickel enrichment of the target products without resorting to the use of heavy media. So the selection of the magnetic fraction from the calcined ore allows you to get an additional nickel-enriched fraction. And the effect of the destruction of the silicate base to increase the yield of the dispersed phase enriched with nickel. These two factors make it possible to achieve high nickel recovery in the target products and a relatively low residual content in the silicate base of ores.

The essence of the proposed method is confirmed by examples.

Example 1. Samples of ore material of the Serovskoye deposit weighing 1 kg were crushed on a jaw crusher. Heat treatment of the samples was carried out in a shaft laboratory furnace. The results of representative experiments are presented in table 1.

Table 1 The results of characteristic experiments. Experience number Temperature ° C Time hour Relative magnetic susceptibility The output of the magnetic fraction,% Nickel Enrichment Experience 1 25 - one 0.67 one Experience 2 500 3 4.11 3.45 1.35 Experience 3 550 3 7.49 7.58 1,52 Experience 4 600 3 7.65 7.62 1.48 Experience 5 700 3 7.72 7.63 1,53 Experience 6 800 3 7.74 7.63 1.50 Experience 7 570 0.5 4.82 3.64 1.39 Experience 8 570 one 7.54 7.60 1,50 Experience 9 570 1,5 7.70 7.65 1.55 Experience 10 570 2 7.75 7.67 1.47

Magnetic susceptibility is presented relative to the source ore.

According to table 1, it is seen that the most optimal firing temperature is in the range of 550-600 ° C, and a sufficient firing time of at least one hour.

Example 2. Samples of ore material from the Serovskoye deposit were crushed on a crusher to various sizes. The results of the distribution of Nickel fractions are presented in table 2.

table 2 The results of the experiments Indicators Sample No. 1 Sample No. 2 Sample No. 3 Fraction class, mm 10-5 2-1 0.4-0.2 The yield of fraction,% 38.97 23.82 16.32 Nickel content,% 0.69 0.78 1.05 Nickel yield,% 28.24 17.02 15.33 Fraction class, mm 5-1 1-0.63 0.2-0.16 The yield of fraction,% 24.46 23.38 10.15 Nickel content,% 0.91 0.96 1.09 Nickel yield,% 23.37 20.56 9.90 Fraction class, mm 1-0.4 0.63-0.4 0.16-0.1 The yield of fraction,% 18.98 14.02 13.68 Nickel content,% 1.01 1,07 1.12 Nickel yield 20,13 13.74 13.71 Fraction class, mm -0.4 -0.4 -0.1 The yield of fraction,% 17.59 38.78 59.85 Nickel content,% 1,53 1.37 1.14 Nickel yield 28.26 48.68 61.05

According to table 2, it can be seen that in thin classes the nickel content is greater than in large ones. Depending on the coarseness, the distribution of nickel is different; when grinding to 10 mm, the smaller classes are more enriched in nickel than when grinding to 2 mm and 0.4 mm, but the yield of nickel in finer grinding is greater than in coarse. The most preferred grinding fineness is fineness up to 2-3 mm, because at this size, grain boundaries are most fully revealed and nickel enriches significantly with a sufficient yield in the target fraction. With fine grinding, there is practically no enrichment of small classes over nickel, this can be explained by averaging of the starting material during grinding.

Example 3. Ore of the Serovskoye field, crushed on a crusher to a size of minus 2.0 mm, was separated on a pulsation column at various linear upstream velocities. The column fractionation data are presented in table 3.

Table 3 Column fractionation. Separation indicators Upstream speed, m / h 10 twenty fifty 75 Fine yield 12.5 20,4 29th 33.5 Fine Nickel Content 1.48 1.26 1.19 1,1 Coarse Nickel Content 0.94 0.97 0.94 0.96 Nickel recovery in the target fraction 18.46 25 34.46 36.7 Nickel Enrichment 1,57 1.30 1.26 1.15

When fractioning on a column with a variable hydrodynamic regime at low speeds, the nickel enriches the target fraction significantly, but the yield of the target fraction is not large, with an increase in the ascending flow rate, enrichment of the target fraction decreases, but the nickel yield increases. Thus, during separation on a pulsation column, it is possible to control the enrichment and yield of nickel when the upward flow rate changes.

Claims (1)

A method of enrichment of oxidized nickel ores, including grinding and fractionation, characterized in that the starting material is ground to a maximum particle size of 2.0-3.0, the ground ore is subjected to heat treatment at a temperature of 550-600 ° C for at least one hour, from calcined ore a magnetic fraction is isolated, and a non-magnetic fraction is sent for fractionation in an upward flow with a variable hydrodynamic regime at an upward flow velocity of 30-50 m / h to isolate a fraction minus 0.3 mm.