SU1273194A1 - Method of dressing loose materials - Google Patents

Abstract

METHOD OF BLACKING MATEPIiATIOB, including two-stage air separation with an adjustable suction of the gas-air mixture in the air separation stages, directed counter-current to the movement of the separated material, characterized in that, in order to ensure the effective extraction of graphite from liquid iron waste, the body weight of sucky material will be used to remove the graphite from the liquid separation is carried out from the air flow with bulk material, aimed at this stage of separation in the amount of 0.001-0.05 of the total the course of this flow, while at the first stage of separation create a pressure drop of 290-980 Pa, and at the second stage - 1470-2450 Pa.

Description

The invention relates to the capture, purification and enrichment of graphite dust emissions formed on the enterprise's iron and steel processing and overflow of the molten iron, such as desulphurization, pouring cast iron into the mixer, spout of the mixer tap, slag, casting iron in filling machines and other operations, and can be used in all areas of industry where technological processes are used, associated with the processing of liquid iron or separation of bulk materials.

After various processes and operations for the processing of liquid iron, dust and iron oxides, calcium and other components contain from 15 to 45% of carbon in the form of graphite sang.

The purpose of the invention is to provide the possibility of efficiently separating graphite from liquid iron waste.

The drawing shows a diagram of the implementation of the proposed method.

The graphite-containing emissions formed during the processing of liquid iron are captured at the places of their formation by local aspiration suction 1 and through the pipeline 2 due to the vacuum created by the smoke exhauster 3, are directed to the first stage of separation (enrichment) in the dust collector A, for example, the cyclone TSN-24, separating with a pressure drop in the range of 290 to 980 Pa;

At the same time, an adjustable suction of the gas-air mixture withdrawn from the total gas-air flow in the gas pipeline 2 is carried out in an amount of 0.001-0.05 from the total amount of the gas-air mixture before separation and directed along the gas pipeline 5 countercurrent to the movement of the product being separated into the bottom of the bunker 6 of the dust separator 4,

The amount of suction gas mixture regulate valve 7, installed on the pipeline 6, according to the indications of the dust meter 8 installed on the pipeline 9.

In the first stage, the separators from the dust-gas-air graphite-containing stream are separated and large particles of graphite are precipitated.

The gas-air stream cleared of coarse graphite particles containing medium and small parts (L of graphite and non-graphite impurities) is directed through the gas pipeline 9 to the second stage of separation (enrichment) into dust collectors 10, for example, TsN-P cyclones, where they separate at pressure drops within 1470-2450 Pa. At the same time, an adjustable suction of the gas-air mixture taken from the general gas-air flow in the gas pipeline 9 and guided along the gas pipeline 11 to the lower part of the bunker 12 of the dust collectors 10 is carried out counter-current to the sedimentation movement (separa dust particles.

The suction in the amount of 0.001-0.05 of the total gas-air mixture before the second stage is controlled by the valve 13 installed on the gas pipeline 11, according to the indications of the automatic meter 14 installed on the gas pipeline 15 after the drawers 10.

The gas-air flow is usually sucked with a temperature of 40-120 ° C, which eliminates moisture condensation and sticking of wet bins.

dust.

At the first and second stages of separation, a different pressure drop is created, which determines the effective air enrichment of the graphite containing scale.

The magnitude of the pressure differential in the first stage is 0.12-0.67 in the value of the differential pressure in the second stage.

The enriched graphite product obtained in cyclones of the first and second stages of separation is separately packaged in special containers 16 and sent after the first stage

to consumers as a commodity graphite, and after the second stage - to graphite-processing enterprises for the reuse of h, Other ways of unloading and transportation are possible

obtained graphite product, such as cement trucks.

The gas-air stream purified from graphite particles containing fine oxides of iron, calcium, magnesium, aluminosilicates and others is directed through a gas pipeline 15 to an aftertreatment, for example, into an electrostatic precipitator 17, after which the purge gas is discharged into the atmosphere.

The captured after tertiary treatment, which contains mainly iron oxides and is a valuable iron-containing raw material, is sent for processing and use as an agglomerate at the sinter plant. The exudate is polydisperse and heterogeneous in chemical composition.

The largest amount of graphite is contained in large fractions of dust. The larger the fraction, the greater the content of graphite in it. Thus, in the mixing compartments, in dust larger than 0.16 mm, the content of graphite is from 50 to 90%. During desulfurization and casting of iron, the content of graphite in dust with a particle size of 0.040-0.16 mm is 45-90%. In small fractions, the content of graphite is insignificant; they are mainly represented by oxides of iron, calcium, and magnesium.

According to the data of instrumental studies, with the initial content of graphite in the dust entering with the gas-air flow into cyclones, from 15 to 45% of the graphite in the collected dust is from 20 to 55%.

Such dust is a valuable graphite-containing concentrate, since its content of graphite several times exceeds the content of graphite in natural ore, however, to obtain commercial graphite, this pie requires further complex processing in graphite factories, as it is contaminated with iron oxides and other non-graphical components.

When installing the second and subsequent stages of cyclones with the same pressure differential as in the first stage of the fraction, trapped in the first stage are caught in an insignificant amount, therefore the proportion of graphite trapped in the second stage decreases sharply, and the total number of graphite trapped in both stages increases slightly.

In the proposed method, dust collection and separation of graphite-containing dust are conducted in two successively installed cyclone stages at different pressure drops

In the first stage, cyclones of coarse dust collection are used, for example, TsN-24, with a certain small pressure drop and a relatively low total effi-ciency1) dust collection efficiency, which provides separation (separated) of large-particulate graphite 70-90% from the piezo-air flow of 70–90%, which close to the quality of commercial graphite product - foundry crystalline graphite and either does not require additional enrichment at all, or requires additional enrichment with minimal costs compared to enrichment GOVERNMENTAL ore.

Full air enrichment of graphite powdered waste is carried out simultaneously with the dust collector in the first stage of cyclones - separators, after which the graphite product can be sent to the consumer.

In the second stage of dust collection, separation is carried out in highly efficient cyclones, for example, type TsN-11, with a significantly higher pressure drop than in the first stage. In this case, small particles of graphite, not captured in the first stage, and other components (CaO, MgO, iron oxides) are trapped. The content of graphite and trapped dust is 20–40%, which is less than in the first-stage cyclones, but several times higher than in natural ores. The captured dust is a valuable high-quality graphite concentrate, the cost of which is significantly less re-enriched than natural ore. The third stage of purification (final fine coating) is an electrostatic precipitator, a fabric filter or fine gas discharges and sublimates (mainly iron oxides) come into the wet gas cleaning , practically does not contain graphite.

Research and calculations showed that when the pressure drop at the first stage of separation is less than 290 Pa, the overall dust removal efficiency and separation efficiency of graphite fractions is better; the graphite content in the captured ditch contains less than 70% due to an increase in the proportion of large particles of slag and metal particles containing in small quantities original dust. The captured graphite material with a graphite content of less than 70% does not correspond to the quality of commercial graphite and requires more significant X additional enrichment costs.

With a pressure drop at the first stage of more than 980 Pa, the overall efficiency of the pressure control increases and, apart from large particles containing the largest amount of graphite, small particles with an increased content of graphite-contaminating alumina-silicate, calcium, magnesium and iron oxides also begin to be partially trapped. The content of graphite in the collected dust also contains less than 70% and the resulting graphite material does not correspond to the quality of commercial graphite. When the pressure drop at the second stage of cyclones is less than 1,470 Pa, the overall dust collection efficiency decreases, including by reducing the efficiency of trapping small and medium fractions of graphite. The content of graphite in the collected dust becomes less than 20%, which degrades the quality of the obtained graphite concentrate. When the pressure drop in the second stage is more than 2450 Pa, the efficiency of trapping fine particles of iron oxides, caplets, and magnesium, which contaminate graphite, increases. By increasing the proportion of these particles, the graphite content in the captured material contains less than 20%, which degrades the quality of the granite material obtained.

With optimal pressure drop ranges established during calculations and studies in the first and second separation stages, the optimum ratio of pressure differences in the first stage to the pressure differential in the second stage of separation is from 0.12 to 0.67.

The lower value (0.12) of the ratio range corresponds to the ratio of the minimum pressure drop at the first stage of cyclones to the maximum pressure drop at the second stage. The upper range value corresponds to the ratio of the maximum pressure drop on the first crjrneHH cyclone to the minimum pressure drop. on the second step

Several traces of technological process operations occur in the same area of liquid iron processing, in which the amount of graphite-containing dust, its fractional and chemical composition, in particular, the carbon content varies widely.

in the mixing units of the operation of pouring iron into a mixer, draining the mixer, slag loading). In order to maintain the maximum content of graphite in the dust collected in cyclones in each process of pig iron processing in the proposed method, separation in both stages of the cyclones is carried out with adjustable suction in the lower booker part of the dust collectors. The suction directed countercurrently to the movement of the material caught in the cyclone prevents the fine fractions of dust contaminating graphite from settling out of the cyclone and thus increases the relative content of large particles of graphite in the dust collected. Thus, additional enrichment of the graphite-containing material occurs, i

When the suction value is less than the ratio 0.001, the influence of the suction value on the efficiency of dust collection and the degree of enrichment of graphite-containing dust stops.

When the ratio of the amount of suction to the total amount of gas-air mixture is more than 0.05, the efficiency of dust collection decreases sharply and not only small non-graphitic fractions, but also particles, are taken out of the cyclones. I

The range of variation in the relative magnitude of the suction within the limits of 0.001-0.05 is optimal for all cases of liquid iron processing occurring in ferrous metallurgy.

In addition to automatic regulation of the suction, the suction can be regulated according to a specific program, which is selected when setting up the installation, depending on the characteristics of the process and the characteristics of dust and gas emissions. With this, an optimum graphite content in the captured and obrazovanny product is provided. It is also possible to manually adjust the suction by the operator in the course of the technological process based on the same conditions.

On the basis of preliminary studies and calculations, an example is given of the method for enriching the dust-like graphite-containing emissions resulting from cast iron desulfuration, the following chemical composition of dust,%: C 51.09; MgO 26.5j Fe, 0j 19.5; CaO, 2.91. A gas-air mixture captured by aspiration suction (umbrellas) with graphite-containing dust in the number 380000 with a temperature of 80 ° C, an initial dust content of 2.2 g / m and a volume weight of 1.5 t / m is directed through a gas pipeline to the first stage of separation (enrichment) in a cyclone TSN-24 in which under the action of centrifugal forces, with a pressure drop of 530 Pa, created by the smoke exhauster and the cyclone design, and adjustable suction of the gas-air mixture in the amount of 9000 (0.0236 of the total flow), taken from the total gas-air flow before the first stage and n Directed to the lower part of the cyclone bunker to meet the precipitating dust, large particles (more than 40 microns) of graphite are accumulated and deposited in the cyclone bunker in the amount of 418 kg / h. The composition of graphite concentrate after the first stage,%: C 76.1; MgO 16.3; 6.6; CaO 1.0 Purified gas-air mixture from large fraction graphite in the amount of 380000 m / h with an initial temperature of 78 ° C and a dust content of 1.1 g / m is directed along the gas pipeline to the second separation stage - a group of cyclones CN-P in the amount of 6 pieces, in which under the action of centrifugal forces with a pressure drop of 1860 Pa, generated by the smoke exhauster and cyclone design, and adjustable suction of the gas-air mixture in the amount of 9000 (0.0236 of the total flow) taken from the gas-air flow before the second stage and directed to the lower part of the bins towards dust, smaller particles of graphite-containing dust (less than 40 microns) in an amount of 240 kg / m are deposited in the bunkers of cyclones TsN-11, Composition of graphite concentrate after the second stage,%: C 30.0; MgO 40.3; Fe, j03 25.6; CaO 4.1. Examples of the method with the extreme and average values of the proposed parameters are summarized in Table 1.

290 ZVOORO 80 2.2 C 72.9; MgO 18.55;

580 380000 80 2.2 C 76.1; MgO 16.3;

980 380000 80 2.2 С 70.4; MgO 17.3;

Her, 0? 7.7; Cao 0.85

 6.6; CaO 1.0

Fe203 11.1; CaO - 1,2

Purified graphite dust and gas. Data on the fractional composition of the coal stream containing fine oxides before and after each step of iron, magnesium, calcium, and other directives at average values to the electrostatic precipitator and after the final x parameters are given in

cleaning vyrasyvayut atmosphere. table.2.

1273194

10 Continuation of table 1

Table 2 From table. 2 it follows that in the first separation stage dust particles with a particle size of more than 40 microns separate, in the second stage less than 40 microns. In the electrostatic precipitator, generally particles of 10-20 microns are separated. Data on the content of graphite in the collected dust with average values of the parameters are given in Table 3. T Blitz 3 Contents Sizes Fraction content, microns of graphite graphite in dust collected in pypi, first stulted during separation,% of the second stage of separation D1I,% More than 60 1273194 standards with W 2 Continuation of table 3 Total: From table . 3 it can be seen that after two-stage separation of graphite-containing dust emissions, graphite concentrate with a content of graphite of 76.1% is obtained on the first stuni, and 30% is obtained at the second stage.

Claims (1)

METHOD OF ENRICHMENT OF BULK MATERIALS, including two-stage air separation with an adjustable suction of the gas-air mixture in the air separation steps directed countercurrent to the movement of the separated material, characterized in that, in order to enable the efficient extraction of graphite from waste liquid iron, the suction of the gas-air mixture at each stage of the air-gas mixture carried out from the air stream with bulk material directed to this separation stage in the amount of 0.001-0.05 of the total flow The ode of this flow, while the separation fines are created by laziness 290-980 Pa, 1470-2450 Pa USSR 1963 with the first gear N0 GO> I