RU2822622C1 - Method of producing magnetite concentrates for producing pellets for metallization of normal and premium quality - Google Patents

Abstract

FIELD: mineral processing.

SUBSTANCE: proposed invention relates to mineral processing by reverse cation flotation and can be used in flotation of crushed ferruginous quartzites to reduce content of silicon dioxide and increase quality of total iron content at its maximum extraction. Method of producing magnetite concentrates for the production of pellets for metallization involves agitation of pulp with flotation reagents, subsequent main flotation in pneumatic mechanical flotation machines to obtain foam and chamber products, direction of the main flotation foam product for agitation in the presence of flotation reagents and for subsequent count flotation in pneumatic mechanical flotation machines to obtain foam and chamber products, combining chamber products of the main and first recleaning flotation to obtain a flotation concentrate, agitation of foam product of the first cleaner flotation in the presence of flotation reagents and its direction for the second cleaner flotation in flotation machines of column type with production of middling product and flotation tailings. Agitation of the pulp before the main and recleaning flotation is carried out first in the presence of flotation reagents-depressor and a regulator, and then in the presence of a cationic collector. Agitation before the main flotation is carried out for 4–5 minutes, and before the first and second cleaner flotation for 3–4 minutes. Main flotation is carried out for 12–13 minutes at the following reagent mode: depressant consumption—450–600 g per one ton of flotation feed; consumption of cationic collector—40–60 g per one ton of flotation feed; flow rate of the medium regulator is 200–250 g per one ton of flotation feed. Cleaning operations are carried out at the following reagent mode: depressor consumption—450–650 g per one ton of flotation feed; consumption of cationic collector—10–20 g per one ton of flotation feed; flow rate of the medium regulator is 50–100 g per one ton of flotation feed. In the main and recleaning flotation, a combined flotation concentrate is obtained with total iron quality in range of 70.8% to 71.4%, and in silicon dioxide from 1.52% to 0.90%.

EFFECT: upgraded quality of iron-ore concentrate, minimized losses of iron with waste tailings for achievement of maximum extraction of iron of 97.0% without additional preparatory operations.

4 cl, 1 dwg, 1 tbl

Description

The invention relates to the technology of mineral processing by reverse cation flotation and can be used in the flotation of crushed ferruginous quartzites to reduce the silicon dioxide content and improve the quality of total iron content with maximum extraction.

One of the popular and most accessible methods for processing finely disseminated ferruginous quartzites is magnetic separation. However, there are a number of disadvantages of magnetic enrichment for finely disseminated ores: low contrast of the magnetic properties of ore and non-ore minerals due to the presence of a large number of intergrowths during coarse grinding of ore; poor selectivity of magnetic enrichment for removing silicon dioxide during fine grinding of ore; instability of the process due to variability in the material composition and dissemination of ferruginous quartzites.

At Lebedinsky GOK JSC, ferruginous quartzites are used by magnetic methods to produce an ordinary concentrate with a mass fraction of total iron from 68.2% to 68.6%, silicon dioxide from 5.0% to 4.5%. Additionally, provision is made for finishing part of the ordinary concentrate by regrinding it and enriching it using magnetic methods. The maximum value for quality when additional enrichment of ordinary concentrate by magnetic methods reaches 70.0-70.4% for total iron and 2.7-2.5% for silicon dioxide. The current trends in metallurgy are aimed at a gradual transition from blast furnace smelting to direct reduction of iron with the production of hot briquetted iron. The need to obtain concentrates for the production of pellets for metallization is due to the need of metallurgists to transition to modern economically and environmentally efficient methods of steel production, such as direct iron reduction technology, which requires pellets with a high metal content and low silicon content.

The use of the reverse cationic flotation method for finishing iron ore concentrates is a relevant and selective method that makes it possible to obtain commercial concentrates with high iron extraction, will improve the quality of iron ore products when preparing iron ores for metallurgical processing, and will ensure the production of concentrates with quality characteristics of at least 70.8% iron content and not higher than 1.52% silicon dioxide content, suitable for the production of pellets for metallization of regular (up to 2.0% silicon dioxide content) and premium (up to 1.5% silicon dioxide content) quality, which are in high demand for market.

The most pressing issues in the flotation finishing of iron ore concentrates is the stabilization of the flotation process with the production of high-quality concentrates with quality characteristics of no lower than 70.8% iron content and no higher than 1.52% silicon dioxide content, suitable for the production of pellets for metallization of conventional (up to 2 .0% silica content) or premium (up to 1.5% silica content) quality, while ensuring consistent quality performance to minimize iron losses from tailings to achieve maximum iron recovery. For example, to obtain pellets for metallization of normal (up to 2.0% silicon dioxide content) quality, it is necessary to obtain high-quality magnetite concentrates with a total iron content of 70.8%, silicon dioxide no more than 1.52%, while reducing the iron content and increasing the content silicon will lead to the release of defective metallurgical processing products (pellets), and an increase in iron content/decrease in silicon content by more than 0.2-0.3% will lead to unjustified losses in iron extraction in tailings in the enrichment process. A similar situation occurs when obtaining concentrates with an iron content of 71.4%, silicon dioxide 0.9% to obtain premium quality pellets for metallization (up to 1.5% silicon dioxide content).

There is a known method of flotation finishing of magnetite concentrates, including grinding, conditioning of the pulp with a cationic collector and subsequent main reverse flotation, while the resulting foam product of the main reverse flotation enters the finishing cycle, including the operations of additional grinding, thickening, treatment of the product with modifiers and finishing flotation, the chamber product of which combined with the chamber product of the main flotation to obtain a combined flotation magnetite concentrate (RU, patent No. 2365425, class B03D 1/02, 2007).

There is a known method for increasing the efficiency of production of iron ore concentrates, which involves conditioning the pulp of iron ore concentrates with a depressor, a cationic collector and an environmental regulator, subsequent flotation of silicate minerals in the main flotation, the chamber product of which is subjected to control flotation to obtain a final high-quality low-silica iron ore concentrate in the chamber product and a foam product , which, together with the foam product of the main flotation, is sent to cleaner flotation to obtain foam and chamber products, the chamber product of cleaner flotation is sent to a finishing operation, which involves desliming and magnetic separation to obtain a commercial concentrate of industrial quality and tailings, and the foam product of cleaner flotation is subjected to additional finishing operations involving additional grinding, classification and magnetic separation to produce concentrate and tailings (RU, patent No. 2443474, class. B03D 1/00, B03В7/00, 2010). This method is taken as a prototype.

The disadvantages of the known methods are the low quality of iron content and high silicon quality of the resulting concentrates with low extraction of the useful component due to its high values in the foam product - flotation tails. High complexity, labor intensity and energy intensity of the technological scheme due to the use of additional operations of preparation, grinding, and enrichment. Additional losses associated with over-grinding of products.

The technical result to which the present invention is aimed is to improve the quality of iron ore concentrate to the level and suitability for the production of pellets for metallization of regular or premium quality, stabilize the flotation process to obtain quality indicators, minimize iron losses from waste tailings to achieve maximum iron recovery 97.0% without additional preparatory operations.

The proposed method for obtaining magnetite concentrates for the production of pellets for metallization of regular and premium quality can be used at mining and processing plants in the production of flotation iron ore concentrates.

The specified technical result is achieved by implementing a method for producing magnetite concentrates for the production of pellets for metallization of regular and premium quality, including conditioning the iron ore concentrate pulp with a depressor, a cationic collector and an environment regulator, subsequent main reverse flotation carried out in pneumomechanical flotation machines, producing foam and chamber products , the foam product of the main flotation is supplied for conditioning with a depressor, a cationic collector and an environment regulator and the subsequent first cleaning operation carried out in rotor-mechanical flotation machines, and the quality indicators and yield of the chamber product, which is fed to the combination with the chamber product of the main flotation, are regulated in the process so that in order to maintain the quality level in the combined final concentrate within a given range (for example, 70.8% total iron content, 1.52% silicon dioxide content), and the froth product is sent to the second cleaner flotation, and this operation is carried out in column-type flotation machines with using at least two machines that produce middling product, which is mixed with ordinary concentrate obtained at Lebedinsky GOK using magnetic technology, and depleted foam, which is waste tailings. An aliphatic amino ester of 5-10% concentration, a mixture of amines and diamino esters or a mixture of alkyl ester amines and diamines are used as a cationic collector; hydrolyzed yellow or fawn dextrin is used as a depressant of iron ore minerals in the form of a mixture of dextrin and alkali at a ratio of 4:1, 5-10 % solution, a 5-10% alkali solution is used as an environmental regulator, and flotation is carried out at a pulp pH value of 9.8.

Distinctive features of the proposed method for obtaining magnetite concentrates for the production of pellets for metallization of regular and premium quality are the use in the scheme of a combination of flotation machines of different types (pneumo-mechanical in the main and first cleaner flotation, column type in the second cleaner flotation). Pneumo-mechanical machines provide high productivity, obtaining the required level of quality and removal of silica, column-type machines provide high separation selectivity for removing silica in the second cleaner flotation and, as a result, maximum recovery of iron into the chamber product and minimum iron content in the foam product. This solution eliminates additional preparatory operations and the need for additional grinding of products. The ability to produce flotation concentrate suitable for the production of pellets for metallization of regular and premium quality, in the range of concentrate quality values for total iron from 70.8% to 71.4%; for silicon dioxide from 1.52% to 0.90% is ensured by maintaining the main flotation mode in the operation to obtain maximum quality, and adjusting the required value of the maintained quality of the final concentrate (for example, 70.8% for total iron content, 1.52% for silicon dioxide), formed from chamber products of the main and first cleaner flotation, is produced by adjusting the qualitative and quantitative characteristics of the chamber product obtained in the first cleaner flotation. Due to the fact that the yield of the chamber product of the main flotation is more than 12-15 times higher than the yield of the chamber product of the cleaner flotation, the adjustment of the quality indicators of the final flotation concentrate suitable for the production of pellets for metallization of regular and premium quality occurs more smoothly, allowing you to maintain the specified value and , accordingly, there will be no loss of iron extraction associated with the need for quality reinsurance in order to avoid defects. The use of two units of low-power equipment in the second cleaner flotation and the use of column-type machines allows you to operate either one machine or two in the required range of feed performance, reagent modes, flotation time, vary the yield and quality of the chamber product and maintain losses in the discharge product at a stable level low level not higher than 26% of total iron content. For example, when the circuit operates to obtain a quality of iron of 71.4%, silicon dioxide of 0.90%, the yield of flotation concentrate will be about 92.8%, respectively, the supply of the second cleaning flotation will be 7.2% in terms of yield from the initial supply of the circuit and to obtain The required level of iron in flotation tailings will require the operation of two column machines with a certain flotation time. When switching to a different concentrate quality, for example 70.8%, or changing the circuit power quality, the power output of the second cleaner flotation may decrease to 4.5% and a smaller flotation front will be required (one column flotation cell) with an increase or decrease in flotation time. Thus, the use of two units of low-power equipment in the second cleaner flotation and the use of column-type machines will minimize losses with the discharge foam product (flotation tailings) to the level of 26.0% in iron content and stabilize the quality of the middling product at the required level 53.8-54, 4% iron content. The developed technological scheme has prospects for use for removing other harmful impurities (alkali metal oxides, sulfur, etc.) from the supplied food when using complex collector reagents.

The invention - a method for obtaining magnetite concentrates for the production of pellets for metallization is illustrated by the diagram presented in Fig. 1.

Before flotation, ferruginous quartzites of the Lebedinskoye deposit are subjected to crushing, magnetic separation, classification, desliming to obtain an ordinary concentrate (mass fraction of total iron 68.6%, silicon dioxide - 4.5%). Part of the ordinary concentrate is supplied for additional enrichment. The re-enriched concentrate is produced using magnetic enrichment technology with preliminary grinding to a particle size of 97-98% of the control size class minus 0.045 mm and the production of a re-enriched iron ore concentrate with a mass fraction of total iron of 70.0% and silicon dioxide - 2.7%.

The proposed technological scheme ensures the production of magnetite concentrates for the production of pellets for metallization by flotation. The initial feed for the technological scheme is a re-enriched iron ore concentrate with a mass fraction of total iron of 70.0% and silicon dioxide - 2.7% or a mixture of ordinary and re-enriched concentrates in a ratio of up to 20/80% (ordinary/re-enriched). Thus, the proposed scheme will ensure the production of magnetite concentrates for the production of pellets for metallization with a given quality in terms of total iron / silicon dioxide content of 70.8/1.5% or 71.4/0.9% or any intermediate for the production of pellets for metallization of conventional and premium quality by flotation method in the range of quality food characteristics in terms of mass fraction of total iron from 69.5% to 70.0%.

The technological scheme provides for flotation enrichment and includes the main and two cleaning flotations.

Reagents for use in the technological scheme are prepared in the reagent facilities of the flotation department. Hydrolyzed corn yellow or fawn dextrin is corn yellow or fawn dextrin hydrolyzed with alkali (caustic soda) at a ratio of 4:1 and further diluted with water to 5-10% concentration, and the medium regulator is a 5-10% aqueous solution of alkali - caustic soda, the cationic collector (aliphatic amino ester, mixture of amines and diamino esters, or mixture of alkyl ester amines and diamines) is diluted with water to 5-10% concentration.

The initial feed is supplied to the operation of agitating the pulp of the original iron ore concentrates with a depressor and an environmental regulator into the first contact tank, then flows by gravity into the second contact tank, where the pulp is agitated with a cationic collector and by gravity flows into the main flotation. The main flotation involves the installation of pneumomechanical flotation machines. The reagent mode of the main flotation is selected to obtain a chamber product with quality indicators at the level of 71.3-71.4% of total iron content and 0.9-0.8% of silicon dioxide content, respectively, which exceeds the indicators of the concentrate required for the production of pellets for conventional metallization or premium quality. The foam product of the main flotation is sent for agitation with a depressant and an environment regulator into a contact tank, then flows by gravity into the next contact tank, where the pulp is agitated with a cationic collector and by gravity flows into the first cleaning flotation, which is also carried out in pneumomechanical flotation machines. The operating mode of the first cleaner flotation is configured in such a way as to obtain qualitative and quantitative indicators of the chamber product going into the mixture with the chamber product of the main flotation with indicators ensuring the production of a combined concentrate (total iron content / silicon dioxide 70.8/1.52% or 71 .4/0.9%) for the production of pellets for metallization of regular or premium quality. The foam product of the first cleaner flotation is sent for agitation with a depressor and an environment regulator in a contact tank, then flows by gravity into the next contact tank, where the pulp is agitated with a cationic collector and then enters the second cleaner flotation, in which column-type flotation machines are used to ensure a front range flotation due to the installation of at least two units of low-power equipment, which provide, with different feed capacities, high selectivity of the process and the production of a lean foam product - waste tailings. The chamber product of the second cleaning flotation is a middling product that is mixed with ordinary concentrate obtained at the Lebedinsky GOK.

The main flotation is carried out in pneumomechanical machines using the following reagent mode:

agitation 1 (with depressor and environmental regulator) - 4-5 minutes;

agitation 2 (with collector) -4-5 minutes;

main flotation time - 12-13 minutes;
depressant consumption - 450-600 g per ton of operation feed;
collector consumption - 40-60 g per ton of flotation feed;
medium regulator consumption - 200-250 g per ton of flotation feed

The first cleaning flotation is carried out in pneumomechanical machines using the following reagent mode:

agitation 1 (with depressor and environmental regulator) - 3-4 minutes;

agitation 2 (with collector) -3-4 minutes;

the time of the first cleaning flotation is 17-18 minutes;
depressant consumption - 450-650 g per ton of operation feed;
collector consumption - 10-20 g per ton of flotation feed;
consumption of the medium regulator is 50-100 g per ton of flotation feed.

The second cleaning flotation is carried out in column-type machines with the following reagent mode:

agitation 1 (with depressor and environmental regulator) - 3-4 minutes;

agitation 2 (with collector) -3-4 minutes;

time of the second cleaning flotation - depending on the flotation front
depressant consumption - 450-650 g per ton of operation feed;
collector consumption - 10-20 g per ton of flotation feed;
consumption of the medium regulator is 50-100 g per ton of flotation feed.

This invention provides the production of the concentrate necessary for the production of pellets for metallization of regular or premium quality with an increase in the extraction of iron in concentrates to the level of 95.1-97.0%, obtaining an industrial product involved in the production of ordinary concentrate of the Lebedinsky GOK with an iron content of 53.8- 54.4%, and reducing iron losses in flotation tailings to a level of no more than 0.6% in terms of iron recovery, with an iron content in the tailings of no more than 26%.

According to the presented scheme of the method for obtaining magnetite concentrates for the production of pellets for metallization of regular and premium quality, products with the following quality characteristics will be obtained:

- iron ore flotation concentrate with a total iron content of 70.8-71.4%, silicon dioxide - 1.50-0.90% with an iron recovery of 95.1-97.0%. The yield will be 92.8-95.5%;

- flotation middling product with a total iron content of 53.8-54.4%. There are two options for using the middling product: a) for mixing with an ordinary concentrate with a total iron content of 68.2% with further shipment to consumers; b) for regrinding and finishing in the enrichment shop.

Flotation enrichment waste is flotation tailings with a total iron content of no more than 26.0%, silicon dioxide of no less than 62.5%. The tailings yield will be no higher than 1.5%.

Maximum extraction of a valuable component (iron) into the concentrate and middling product, and, consequently, a low yield of flotation enrichment waste, is ensured by the use of column-type flotation machines with variability in the flotation front in the second cleaning flotation, maintaining the required range of qualitative and quantitative indicators of the final flotation concentrate.

The proposed flotation concentration scheme will significantly improve the quality of the produced iron ore concentrate: increase the mass fraction of total iron to 71.4%, reduce the mass fraction of silicon dioxide to 0.9%. The scheme makes it possible to produce a concentrate with a range of quality characteristics from 70.8% to 71.4% for total iron, from 1.52% to 0.9% for silicon dioxide. Table 1 shows a planned and confirmed example of the technological balance of products in the production of concentrate to obtain pellets for metallization of normal quality.

Table 1 - Balance of products in the production of concentrate to obtain pellets of normal quality.

Product name Product yield,% Mass fraction of total iron,% Mass fraction of silicon dioxide,% Iron extraction,% Incoming Ordinary iron ore concentrate 20 68.5 4.2 19.7 Re-enriched iron ore concentrate 80 70 2.7 80.3 TOTAL: 100 69.7 3 100 It turns out Concentrate for pellets 95.5 70.8 1.52 97.0 Industrial product 3.2 54.4 21.8 2.5 Total iron ore product 98.7 70.3 2.2 99.5 Tails 1.3 26 62.5 0.5 TOTAL: 100 69.7 3.0 100

The commercial concentrate fully meets the increased requirements of metallurgical processing consumers and is suitable for the production of pellets for metallization, which are in high demand on the market.

The use of this technological scheme and process techniques for finishing iron ore concentrates using flotation will make it possible to obtain premium quality in terms of total iron and silicon dioxide content without additional grinding operations. The use of pneumo-mechanical flotation machines in the main and cleaner flotation, and column-type flotation machines in the second cleaner flotation will ensure maximum extraction of the valuable component (iron), and, consequently, a low yield of flotation enrichment waste.

The proposed solutions have promise for removing other harmful impurities (alkali metal oxides, sulfur, etc.) using complex collector reagents.

The proposed solutions will ensure a reduction in the costs of energy and material resources, therefore, will have a positive impact on the cost of manufactured products.

Claims (4)

1. A method for producing magnetite concentrates for the production of pellets for metallization, including agitation of the pulp with flotation reagents, subsequent main flotation in rotor-mechanical flotation machines to obtain foam and chamber products, direction of the foam product of the main flotation for agitation in the presence of flotation reagents and for subsequent counter-flotation in rotor-mechanical flotation machines flotation machines to produce foam and chamber products, combining chamber products of the main and first cleaner flotation to produce a flotation concentrate, agitating the foam product of the first cleaner flotation in the presence of flotation reagents and sending it to the second cleaner flotation in column-type flotation machines to obtain middling product and flotation tailings, characterized in that that the agitation of the pulp before the main and cleaner flotations is carried out first in the presence of flotation reagents - a depressant and a regulator, and then in the presence of a cationic collector, and agitation before the main flotation is carried out for 4-5 minutes, and before the first and second cleaner flotations for 3 -4 minutes, while the main flotation is carried out for 12-13 minutes with the following reagent mode: depressant consumption - 450-600 g per ton of flotation feed; consumption of cationic collector - 40-60 g per ton of flotation feed; medium regulator consumption is 200-250 g per ton of flotation feed, and cleaning operations are carried out under the following reagent mode: depressant consumption - 450-650 g per ton of flotation feed; consumption of cationic collector - 10-20 g per ton of flotation feed; consumption of the medium regulator is 50-100 g per ton of flotation feed, and in the main and cleaning flotation a combined flotation concentrate is obtained with quality indicators for total iron ranging from 70.8% to 71.4%, for silicon dioxide from 1.52% up to 0.90%. 2. The method according to claim 1, characterized in that hydrolyzed corn yellow or fawn dextrin is used as a depressant in the form of a mixture of dextrin and alkali at a ratio of 4:1, diluted with water to 5-10% concentration. 3. The method according to claim 1, characterized in that an aliphatic amino ester, a mixture of amines and diamino esters, or a mixture of alkyl ester amines and diamines diluted with water to 5-10% concentration is used as a cationic collector. 4. The method according to claim 1, characterized in that a 5-10% aqueous solution of alkali - caustic soda - is used as an environmental regulator.