RU2388544C1 - Procedure for production of collective concentrate out of mixed fine ingrained iron ore - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to concentrating fine ingrained mixed magnetite-martite-hematite-hetite containing iron ore and can be implemented in mining and metallurgical industry. The procedure for production of collective concentrate out of mixed fine ingrained iron ore consists in crumbling source ore, in hydraulic classification with obtaining drained and sand product, in magnet separation and in gravitation concentration. Crumbled to (-2.0)÷(-0.16) mm and classified ore is subject to main and cleaner operations of gravitational concentration in hydro-cyclones with cone angle 30° producing collective magnetite-martite-hematite-hetite concentrate and slime. Tails of main gravitation concentration are subject to hydraulic classification; sands of which are united with tails of gravitation cleaning; further they are classified on a screen with dimension of grain 0.1 mm. Through product is subject to wet magnet separation, whereupon magnet fraction is extracted and united with collective concentrate of gravitation concentration. Drainage of hydraulic classification, top size screen product and non-magnet fraction of magnet separation is directed to waste pile. Pulp is supplied to the hydro-cyclone with contents of solid within limits 34-7 % under pressure 0.5-0.7 kg/cm² while maintaining ratio of solid in source pulp to contents of solid in drainage of the hydro-cyclone within 1.47-1.32.

EFFECT: increased efficiency of collective concentrate production and upgraded quality.

2 cl, 1 dwg, 1 tbl

Description

The invention relates to the field of enrichment of finely disseminated mixed magnetite-martite-hematite-goethite-containing iron ores and can be used in the mining and metallurgical industries.

To date, most of the deposits of rich and easily-concentrated iron ores have already been worked out, and therefore the problem of involving finely disseminated ores of complex mixed composition has arisen. This circumstance requires the creation of new technologies that provide sufficient technical and economic efficiency for obtaining iron ore concentrates.

An object of the invention is the creation of a highly efficient technology for producing high-quality collective concentrate from finely disseminated iron-containing ores of mixed composition.

Two approaches are known to solve the problem of extracting useful iron-containing minerals:

1. The sequential extraction of useful minerals, which primarily ensures the production of magnetite concentrate, according to the traditional technology of magnetic enrichment, followed by the enrichment of the tailings of the magneto-enrichment technology with flotation, gravitational and magnetic enrichment in high magnetic fields (see “Ore dressing” 2007, No. 6 , “Tests of the technology for producing hematite concentrates from the tailings of the beneficiation plant of Mikhailovsky GOK OJSC S.I. Kretov, S. L. Gubin, G. V. Ignatova, V. A. Sentemova, Yu.S. B znogova).

The disadvantages of the method are the high energy intensity of the enrichment process associated with multi-stage enrichment on magnetic separators, low efficiency due to significant circulation loads on the main grinding process and the loss of valuable components with tailings at various stages of enrichment.

A known method of processing wastes from the enrichment of ferruginous quartzites (non-magnetic iron minerals) by gravitational methods. A method for producing hematite concentrate includes screening and enrichment in hydrocyclones. The enrichment is carried out in a short-cone hydrocyclone with a taper angle of 120 °, the sands of the short-cone hydrocyclone are sent to regrind, regrind sands are classified and sent to short-cone hydrocyclones of smaller diameter with a taper angle of 120 ° (see RF patent No. 2296623, B03B 7/00.04, publ. 2004)

The disadvantages of this method include the high energy and capital intensity due to the construction of new production lines for the production of low-quality hematite concentrates (~ 50% Fe total) from the tailings of the processing plant.

A known method of enrichment of magnetite ore, including grinding, followed by gravity separation into heavy sand and light discharge products, after which the light discharge product is subjected to magnetic separation to obtain magnetic and non-magnetic products, while the non-magnetic product is removed from the process and dumped, and the magnetic product sent to the power of the mill. The heavy sand product is subjected to regrinding and subsequent magnetic separation to obtain magnetic and non-magnetic products, while the non-magnetic product is removed from the process and dumped (see RF patent No. 2307710, B03B 7/00, publ. 10.10.2007).

The disadvantage of this method is that the method does not provide the allocation of collective concentrate in the case of enrichment of mixed, magnetite-hematite-martite ores, since the heavy fraction of gravitational enrichment is subjected to magnetic separation to obtain a magnetic fraction (magnetic product) and a non-magnetic fraction sent to the dump together with weakly magnetic minerals (hematite, goethite).

2. Extraction of all useful minerals into a collective iron-containing concentrate in a single technological cycle, which does not require the repetition of a number of technological operations (deslaminating and regrinding), as provided for in technologies for additional extraction of hematite from the tailings of the magnetizing plant.

A known method of enrichment of magnetite-hematite ores, carried out by magnetic-gravity technology at Olenegorsk O.F. (see "Guide to ore dressing", volume 3. Moscow, Nedra, 1974, p. 215) The method is adopted as a prototype.

The technological scheme of the enrichment of magnetite-hematite ores includes the processes of:

- ore grinding;

- hydraulic classification;

- separate operations of magnetic enrichment of sands and discharge of hydraulic classification;

- magnetic staged enrichment of fine-grained fractions;

- regrinding of rough concentrates of magnetic enrichment;

- gravitational enrichment of the tailings of the main operation of magnetic separation on jigging machines and jet concentrators.

The main disadvantages of the known method for producing collective magnetite-hematite concentrate should include:

1. High energy costs associated with the unjustified regrinding of large open grains of useful minerals and multi-stage enrichment on magnetic separators (5 stages), as well as significant circulating loads on the main process of grinding products from the granular part of the crude concentrate, the main magnetic separation and industrial products of jigging machines.

2. The low efficiency of the processes of hydraulic classification in hydrocyclones, due to the increased content of thin classes of ore in the sand product, aimed at regrinding.

3. The use of low-performance equipment for gravitational enrichment (jigging machines, jet concentrators) of finely ground material.

The technical result of the invention is the simplification of the technological scheme, reducing energy intensity by reducing the number of stages of magnetic enrichment and improving the quality of the concentrate.

The technical result is achieved by the fact that in the method for producing a collective concentrate from mixed finely disseminated iron ores, including grinding of the initial ore, hydraulic classification to produce a drain and sand product, magnetic separation and gravity concentration, crushed according to the invention to (-0.20) ÷ (- 0.16) mm and the classified ore is subjected to two-stage gravity enrichment in the main and downstream operations carried out in hydrocyclones with a taper angle of 30 ° to obtain a collective th magnetite hematite-martite concentrate and tails; the tails of the main gravitational enrichment are subjected to hydraulic classification, the sands of which are combined with the tails of the roughing operation, followed by classification on a 0.1 mm grain screen; the sublattice product is subjected to wet magnetic separation with the release of a magnetic fraction, which is combined with a collective concentrate of gravitational enrichment; plums of hydraulic classification, over-screening product of the screen and non-magnetic fraction of magnetic separation are sent to the dump; while for gravitational enrichment in the hydrocyclone serves pulp with a solid content in the range of 34-37% under a pressure of 0.5-0.7 kg / cm ² while maintaining the ratio of the solid content in the original pulp to the solid content in the discharge of the hydrocyclone within 1, 47-1.32.

The essence of the invention lies in the fact that, in contrast to the prototype in the claimed invention, the initial ore is crushed to a particle size of (-0.20 ÷ (-0.16) mm, subjected to hydraulic classification, the sands of which are subjected to gravitational enrichment in the main and cleaning operations carried out in hydrocyclone with a taper angle of 30 °. In this case, pulp with a solid content in the range of 34-37% under a pressure of 0.5-0.7 kg / cm ^{2 is} fed into the hydrocyclone, with a ratio of the solid content in the initial pulp (ρ _ref ) to the solid content in the discharge of a hydrocyclone (ρ _cl ) in p within the limits of 1.47-1.32 The claimed modes provide an effective separation of minerals by density and concentration in the sand product of discovered grains of useful minerals: magnetite, hematite, martite, goethite, whose density is more than 4.5 g / cm ³ , with a low content iron-rich splices.

Mineral waste materials with a density of less than 3.2 g / cm ³ , ordinary and poor splices and the finest open grains of useful minerals are released into the drain product (tails of gravitational enrichment). Refinement of the drain product by magnetic separation is impractical due to the low separation efficiency of such a difficult to recycle material.

Further enrichment of gravity enrichment drain products is based on the use of differences in the linear dimensions of the spliced and disclosed material, for which the process of fine screening of 0.1 mm grain is used; at the same time, rock-forming minerals and their poor splices are sent to the oversize product, which are sent to the dump, and open grains of magnetite, martite and rock-forming minerals are extracted into the oversize product, which are enriched in magnetic separators to obtain high-quality iron-containing concentrate.

Justification of the modes

Grinding the initial magnetite-martite-hematite-goethite-containing ore to obtain grains with a grain size of (-0.20) ÷ (-0.16) mm provides a selective disclosure of useful minerals by 85-90%.

Grinding the ore to obtain grains with a grain size of more than -0.20 mm reduces the amount of selectively discovered beneficial minerals.

Grinding ore to obtain grains with a particle size of less than -0.16 mm leads to the sludging of useful minerals.

The solid content in the feed (ρ _out %) should be between 34-37%. More diluted pulps with a solids content of less than 34% contribute to the operation of the hydrocyclone in the classification mode, and denser pulps with a solids content of more than 37% have an increased viscosity that impedes the process of separation of minerals by their density.

An effective separation of minerals by density occurs at a certain ratio of the solids content in the initial pulp (ρ _ref ) to the solids content of the hydrocyclone in the plum (ρ _sl ). This ratio is in the range of 1.47-1.32. In this case, the ratio of the diameters of the drain and sand nozzles is maintained, as when the hydrocyclone is in the hydraulic classification mode. When the hydrocyclone is in gravity enrichment mode, the effect of the diameter of the drain nozzle is insignificant. The drain nozzle should not create resistance to the outlet of the drain product (Table 1).

Classification of tails of gravitational enrichment by grain of 0.1 mm leads to the concentration of free open grains of magnetite and martite in the under-sieve product, and rock-forming minerals, poor and ordinary splices with an iron content of not more than 7-8% accumulate in the oversize product.

An example of the method

The drawing shows a diagram and key indicators of the beneficiation of finely disseminated magnetite-martite-hematite ores of the Tagarsky deposit.

The studies were carried out on a representative ore sample with a mass fraction of iron of 42.46% total and magnetite 20.1%.

After crushing, grinding and hydraulic classification, a fraction of -0.16 + 0.02 mm was directed to gravity enrichment in a GTs-75 hydrocyclone with a taper angle of 30 ° and a capacity of 1.0-1.5 t / h for feeding the hydrocyclone. The pulp with a solid content of 35% was fed into the hydrocyclone at a pressure of 0.6 kg / cm, while maintaining the ratio (ρ _ref ) / (ρ _sl ) = 1.40. The resulting concentrate was subjected to purification in a hydrocyclone HZ-75 with a taper angle of 30 ° with the same modes.

As a result of two gravity enrichment operations in hydrocyclones, a collective concentrate was obtained with a total iron content of 63.5%, represented by open grains of useful minerals. In the main operation, the total iron content increased from 47.62% to 56.56% and in the cleaning operation - from 56.56% to 63.5%. The yield of collective gravity concentrate was 33.86% with the extraction of 50.62% of the original ore.

The tails of gravity enrichment were classified on a Krosh screen with the release of an oversize product with a grain size of +0.1 mm, sent to the dump. The classification of gravity dressing tailings on sieves with a hole size of 0.1 mm ensures the output of rock-forming minerals and their intergrowths into an oversize product with a total iron content of Fe _total - 7.08%. This circumstance largely leads to a simplification of the enrichment technology by eliminating the stage-by-stage regrinding of intermediate products.

The under-sieve product of the screen with a particle size of -0.1 mm was sent to wet magnetic separation (MMS) to a 120T-SEM separator. The magnetic fraction is the final martite-magnetite concentrate containing 66.8% of the total iron when extracting 40.62% of the original ore, and the non-magnetic fraction was sent to the dump. In the absence of intergrowth material in the sublattice product, its magnetic enrichment is very effective. When the total iron content in the diet was 56.0% Fe _total , the total iron content in the magnetic fraction increased to 66.8%, the tailings contained 9.78% total iron.

The collective concentrate of gravitational enrichment was combined with the magnetic fraction, as a result, a total collective concentrate was obtained containing 65% of the total iron with the extraction of 91.24%, its yield was 59.56%.

When processing finely disseminated iron ores according to the described method, the possibility of obtaining very high technological parameters is shown by the example of ore processing at the Tagarsky deposit. So, with an initial total iron content of 42.46%, a collective iron ore concentrate was obtained with a content of 65.0% with a recovery of 91.24%.

When using the proposed method for processing mixed ores, one should expect the creation of highly profitable processing enterprises by improving technological indicators and significantly reducing capital and operating costs.

Thus, the use of the described invention solves the problem of the integrated use of useful minerals isolated from refractory, finely disseminated mixed iron ores.

Claims (2)

1. A method of obtaining a collective concentrate from mixed finely disseminated iron ores, including grinding the original ore, hydraulic classification to produce a drain and sand product, magnetic separation and gravity concentration, characterized in that it is ground to (-2.0) ÷ (-0.16 ) mm and classified ore are subjected to the main and cleanup operations of gravity concentration in hydrocyclones with a taper angle of 30 ° to obtain collective magnetite-hematite-martite concentrate and tails, the tails of the main gravel italic enrichment is subjected to hydraulic classification, the sands of which are combined with the tails of gravitational scrubbing, followed by classification on a 0.1 mm grain screen, the sublattice product is subjected to wet magnetic separation with the separation of the magnetic fraction, which is combined with a collective concentrate of gravitational enrichment, hydraulic classification plums, sieve product the screen and the non-magnetic fraction of the magnetic separation are sent to the dump. 2. The method according to claim 1, characterized in that the pulp is fed into the hydrocyclone with a solids content in the range of 34-7% under a pressure of 0.5-0.7 kg / cm ² while maintaining the ratio of solids in the original pulp to the solids content in the discharge hydrocyclone in the range of 1.47-1.32.

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