RU2398896C2 - Procedure for sinter machine charging - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention can be used at agglomeration of iron and non-ferrous ore and concentrates to eliminate negative factors causing non-uniform charge sintering in sinter machines at charging. The procedure consists in control over consumption of charge supplied to a charging unit and in charging via a chute onto a conveyor belt of a shuttle distributor operating under a preset mode. A carriage of the distributor travels between borders of a charging funnel and forms a layer of charge on the conveyor belt of the shuttle distributor and in the charging funnel. Charge from the charging funnel is supplied to the sinter machine. The level of charge in the charging funnel and mode of operation of the shuttle distributor is controlled with equal speed of the conveyor belt relative to the chute when the carriage stops at borders of the charging funnel, at forward motion (F) to the further from the chute border of the charging funnel and at back travel (B).

EFFECT: essential improvement of layer of charge forming in charging funnel, raised uniformity of distribution of granules-metric composition, density and fuel in volume of layer, uniform and symmetrical distribution of charge at side walls of charging funnel.

5 dwg, 2 tbl, 2 cl

Description

The invention relates to the field of preparation of raw materials in the ferrous and non-ferrous metallurgy and can be used in the agglomeration of iron and non-ferrous ores and concentrates to eliminate the negative factors causing the unevenness of the process of sintering of the charge on sintering machines.

Known agglomeration process [1], wherein the charge is placed on the pallet sintering machine so that the height of the bed was increased from the pallet center to its sides, wherein the increase should occur on the _^fourth carriage width from the bead on each side and constitute 10% of the bed height in the center. The method, contributing to a certain extent, alignment of the layer resistance along the width of the sintering machine, does not eliminate the root cause of this unevenness created in the loading funnel (SV). In addition, he does not solve the problem of reducing the unevenness of the sintering process in the volume of the central part of the layer, due to the disordered formation of the transverse charge layers in the pollutants, which have different density and distribution of the particle size distribution of the charge and fuel.

There is a method of loading the sinter charge [2], in which the laying of its small fractions to the sides of the pallets is carried out in the charge loading unit due to the directed segregation of the charge in the pollutant. According to the method, the charge level at the edges of the pollutants is increased by increasing the stopping time of the shuttle distributor (PD) carriage, as a result of which larger particles of the charge roll down from the side walls to the center of the slope, and smaller particles remain at the walls.

The method, increasing the gas-dynamic resistance of the charge layer in the peripheral part of the pallet, does not solve the problem of forming uniform transverse layers of the charge in the pollutant. With the alternating movement of the PD and the constant speed of its conveyor belt (CR) and the trolley, layers of different thicknesses are formed on the CR: “thin” - when the CR moves forward from the heat supply of the charge onto it, when the speeds of the CR and the cart are summed; “medium” - when the CR stops and “thick” - when the CR moves backwards, when the total speed is equal to the difference between the speeds of the CR and the cart. This leads to the formation of a “layered cake” with a variable distribution of thickness, density and particle size distribution of individual layers of the charge and fuel along the height and width of the pollutant, including at its borders, and an disordered exit of the layers from the pollutant. As a result, the yield of agglomerate is reduced.

The closest in technical essence and the problem to be solved is the method of loading the charge onto the sinter machine [3], in which the speed of the conveyor belt of the Czech Republic relative to estrus is kept constant when the direction of movement of the Czech Republic changes.

The known method involves the formation on the CL layer of the mixture of the same thickness with alternating movement of the Czech Republic. The method eliminates the formation of transverse layers of a variable in width of the TS thickness in each pass. However, the condition of constant speed of the PD tape relative to estrus is met by an infinite number of uncertain solutions for which the thickness of the layer on the PD tape is the same, and the thickness of the transverse layers in the pollutant in the cycle (passage of the PD forward and backward) is different. So, at a constant CL velocity relative to estrus due to charge accumulation on the CR, a “thin” transverse layer is formed during the forward movement in the SC, and a “thick” layer is formed when moving backward, which also leads to the formation of a “layered cake” in the SC distribution in the transverse layers of particle size distribution, density, particle size and, accordingly, fuel along the height and length of the pollutant. In addition, the method provides for the formation of the same height of the common layer of the charge in the pollutant, without increasing at the side walls of the pollutant. As a result, not only the uniformity of the characteristics of the sintering process in the volume of the layer, but also the uniformity of the sintering process along the width of the pallets, i.e. simultaneous approach of the combustion zone to the grates at the end of the sintering zone. As a result, the productivity of the sintering machine and the yield of sinter are reduced.

In this application, the method of loading the charge onto the sintering machine sets the task of eliminating the disadvantages of the known method, unifying the operating mode of the PD for all charge materials and sizes of sintering machines with an increase in their productivity and yield of sinter.

The essence of the proposed method, designed to solve the problem to achieve a technical result, is that, using individual elements of the known method, including controlling the charge flow supplied to the charge loading unit, loading the charge through estrus to the conveyor belt of the shuttle distributor, the trolley of which moves between the boundaries of the loading funnel with the formation of a layer of the charge on the conveyor belt of the shuttle distributor and in the loading funnel, the issuance of the mixture from the loading funnel to the sintering machine with a dosing device, control of the charge level in the feed hopper and the shuttle dispenser operating mode with the same speed of the conveyor belt relative to estrus when the truck stops at the borders of the feed hopper, when moving forward (B) to the border of the feed hopper far from the estrus and return back ( N), the operation mode of the shuttle distributor is set according to the conditions:

where V _lO1 , V _lO2 - respectively, the CR CR speed in the modes of stops at the nearest to estrus and far from it boundaries of the pollutants forward and backward; V _lv and V _ln -, respectively, the speed of the CR of the Czech Republic in the operation modes forward and backward; V _TV and V _tn - the speed of the CR truck in the modes of operation forward and backward; N _SLO1 and N _SLO2 - respectively, the height of the charge layer at the near and far from estrus boundaries of pollutants at the beginning of the movement of the Czech Republic after stops; N _sl.c is the height of the charge layer in the center of the pollutant at the moment of the end of its intersection with the charge flow from the Czech Republic.

The method is carried out on typical equipment of the charge loading unit (see FIG. 1), including the charge supply of charge 1 to the shuttle distributor, consisting of a conveyor belt 2 and a cart 3 with drives (see the typical design of the shuttle distributor, for example, in [4]) , a loading funnel 4 with a discharge window 5, a drum feeder 6, feeding the charge to the pallets of the sintering machine 7 through the loading tray (not shown in the figure). The charge from estrus 1 enters the conveyor belt 2 of the shuttle distributor, the trolley 3 of which moves between the boundaries O ₁ and O _{2 of the} loading funnel 4, forming layers of the charge 8 and 9, respectively, on the tape 2 and in the funnel 4. From the loading funnel 4, the charge through the unloading window 5 is issued by a drum feeder 6 to continuously moving pallets 7 of an agglomeration machine, forming a layer 10 of a given height on them with a controlled charge flow to the shuttle dispenser. At the borders of O ₁ and O _{2, the} trolley 3 stops with a predetermined time delay, different for each border, after which it changes the direction of movement to the opposite.

The operation mode during alternating motion of the PD with the formation of transverse layers with the same thickness in the pollutant is ensured by condition (1), and with the same layer thickness on the CR, by conditions (2) - (5) using conditions (1) in them.

When the CR truck moves “forward” from the boundary O ₁ to O ₂ , material accumulates on the CR, the maximum volume of which is equal to the product of the CL length between the boundaries O ₁ and O ₂ by the height and width of the charge layer on the CR. Moreover, for the passage of the PD “forward”, the charge arrival in the pollutant is less than the charge supplied during the same time through the estrus 1 to the PD, by the mass of additional material accumulated on the CR. On the contrary, for the passage of the Czech Republic “backward”, the charge arrival in the pollutant is larger by the same amount as compared with the material fed through the estrus 1. In order to ensure the same thickness of the charge layers in the pollutant, the travel time of the PD between the boundaries О ₁ and О _{2 of the} pollutant, and, accordingly, the charge arriving from the estrus on the CR, should be less than when going “forward”, and the speed of the bogie and CR should be greater. At the same time, exactly the mass of the charge that accumulated on the CR should be additionally discharged from the PD in the pollutant. Condition (1), together with (2) and (3), regulates the strict correspondence between the modes of movement of KL 2 and Trolley 3 of the Czech Republic in a cycle, setting the speed of the trolley V _t > V _tv . The formation of the charge layer profile at the edges of the funnel is determined by conditions (4) - (6). Moreover, conditions (4) and (5) are unchanged for all the charges and sizes of sintering machines, and condition (6) is set on the basis of experimental data to determine the coefficient of internal friction of the charge and the optimal excess of the charge level at the SW walls above the center. Using condition (6), layers of greater height are formed at the walls of the pollutant compared to the rest of the layer (see Fig. 1), which ensures reverse segregation of the charge in size on the slope from the side walls to the center of the pollutant, respectively, the concentration of a small part of the charge at the boundaries layer in the pollutant and at the sides of the sinter machine pallets, an increase in the gas-dynamic resistance of the sinter machine and, as a result, the sintering process is aligned over the width of the layer on the sinter machine.

Monitoring and establishing the parameters of the proposed method is carried out with the help of modernized conveyor belt drives and CR trucks, which are equipped with frequency converters, and remote level sensors (for example, radar type) for measuring the charge level in the pollutant at its borders and in the center. The level sensor can also be mounted on the frame of a moving CR truck.

The establishment of the parameters of the PD is as follows (see the example in table 1).

Table 1. Tape speed "back" (V _ln ), m / s Cart speed "back" (V _tn ), m / s The ratio of V _ln / V _tn
(one) Trolley speed "forward" (V _tv ), m / s
(2) Tape speed "forward", (V _lv ), m / s
(3) Belt speed at stop 1 (V _lO1 ), m / s
(four) Belt speed at stop 2 (V _lO2 ), m / s
(5) one 2 3 four 5 6 7 0.80 0.16 5.00 0.107 0.533 0.64 0.64 0.20 4.00 0,120 0.480 0.60 0.60 0.24 3.33 0.129 0.431 0.56 0.56 0.26 3.08 0,132 0.408 0.54 0.54 0.28 2.86 0.135 0.385 0.52 0.52 1.00 0.12 8.33 0,094 0.786 0.88 0.88 0.16 6.25 0.116 0.724 0.84 0.84 0.20 5.00 0.133 0.667 0.80 0.80 0.24 4.17 0.147 0.613 0.76 0.76 0.28 3.57 0.158 0.563 0.72 0.72 1.20 0.12 10.00 0,098 0.982 1,08 1,08 0.16 7.50 0.122 0.918 1,04 1,04 0.20 6.00 0.143 0.857 1.00 1.00 0.24 5.00 0.160 0,800 0.96 0.96

The speed of the belt (V _ln ) is taken as the base when the CR moves from the O ₂ border to the O ₁ border, ranging from the passport to the maximum allowable by technical characteristics (column 1). Then take a number of possible values of the speed of the CR CR V _tn also in the range from the passport to the maximum allowable (column 2). According to condition (1), the corresponding values of the quotient of dividing the received value of V _t and each of the series of V _t values are calculated (column 3). Further, according to conditions (2) and (3), the values of the belt and trolley speed are calculated when the CR moves forward (columns 4 and 5), and according to conditions (4) and (5), when the trolley stops (columns 6 and 7).

In bold type in Table 1, the parameters of the operating mode of the PD are selected, based on which, on a mathematical model that adequately reproduces the conditions for loading the charge into the pollutant, calculations were performed for a real industrial facility - sinter machine AKM-312.

The initial data for the calculation:

- charge consumption - 750 t / h;

- bulk mass of the charge - 1800 kg / m ³ ;

- passport travel speed of the CR truck - 0.24 m / s;

- width of the CR tape - 1400 mm;

- passport speed of movement of the conveyor belt of the Czech Republic - 1.2 m / s;

- length along the axes of the Czech Republic - 12500 mm;

- width of the loading funnel - 4360 mm;

- height of the loading funnel - 2000 mm;

- the height of the discharge opening in the pollutant above the drum feeder is 240 mm;

- the cross section of the funnel is variable in its height: above 1400, below 700 mm;

- the distance from the charge charge estrus in the Czech Republic to the near boundary of the pollutant is 6600 mm;

- width of the outlet of the loading funnel - 4360 mm;

- the slope angle of the mixture, taking into account the height of the fall in the pollutant - 30 ° (respectively, the coefficient of internal friction - 0.577);

- diameter of the drum feeder - 1320 mm;

- rotational speed of the drum feeder - 1.6 min ^-1 ;

- sinter machine pallet speed - 3.7 m / min.

The calculation results on the distribution of the charge in the pollutant during the operation mode of the PD [2], i.e. with the passport speeds of the cart of 0.24 m / s and CR - 1.2 m / s, unchanged in the "cycle" (successive passages of the Czech Republic forward and backward), as well as a specified excess over the rest of the charge level at the boundaries of the pollutant equal to 0.2 m 2 are illustrated. Curve H1 characterizes the profile of the layer that formed on the surface in the pollutant in the previous cycle after the passage of the PD "backward" from the boundary O ₂ to the boundary O ₁ and then lowered down to the outlet of the pollutant. Curve B2 characterizes the profile of the layer in the next cycle after the PD passes forward from the O ₁ border to the O ₂ border, and H2 in the same cycle when the PD returns from the O ₂ border to the O ₁ border. The distance between the curves H1 and B2 characterizes the thickness of the transverse layer when the PD moves forward, and the distance between the curves B2 and H2 - when the PD moves backward. The layers have different thicknesses, besides changing in each layer as the PD moves, the layer profile at the boundaries of the pollutants is not the same. As a result, the charge from the outlet of the pollutant is issued on pallets unevenly and disordered.

The distribution of the charge in the pollutant obtained by the prototype mode, i.e. at the same CL speed relative to estrus and with a minimum deviation of only one of the parameters from the conditions claimed in the invention, the conveyor belt speed V _lv (V _lv = 0.72 m / min, V _tv = 0.16 m / min, V _ln = 1 , 2 m / min, V _tn = 0.24 m / min, V _lO1 = V _lO2 = 0.96 m / s), shown in Fig.3.

As can be seen from figure 3, the thickness of the individual transverse layers of the charge along the width of the funnel stabilized, however, the difference in the thickness of the layers during alternating passages of the Czech Republic even increased compared to the "passport" mode. The growth of deviations of the CR operation parameters from those claimed in the invention is accompanied by an increase in the angle of inclination of the profile curves of the transverse layers with respect to the horizon, i.e. additional uneven delivery of the charge from the pollutant to pallets. The profile of the layers at the boundaries of the pollutants is also different. All this leads to uneven sintering of the charge along the width of the pallets of the sintering machine and in the volume of the layer with a loss in productivity of the sintering machine and a deterioration in the quality of the sinter.

The distribution of the transverse layers in the pollutant according to the dependencies declared in the invention (see table 1, parameters in bold) and the specified excess of the layer at the boundaries of O ₁ and O ₂ equal to 0.2 m, is presented in figure 4.

As you can see, the thickness of the transverse layers in the pollutants is almost the same and they move from top to bottom to the discharge opening of the pollutants uniformly in height and width of the pollutants. In this case, a symmetric and uniform distribution of the charge at the edges of the pollutant is formed. Accordingly, the rational formation of the layer on the sintering machine is ensured both in the volume of the layer and on the sides of the pallets.

The duration of PD stops at the boundaries of the pollutants in the stable operation mode of the boot device depends on the specified excess of the layer above the center. For an example with the claimed parameters, the duration of stops of the Czech Republic at the borders is as follows, with:

Mode of operation border O ₁ border O ₂ uniform loading 0.5 1.7 0.1 m excess 1,2 2.2 0.2 m excess 1.9 3,5 0.3 m excess 3,1 4.6

Due to the accumulation of the mass of the charge on the ribbon of the Czech Republic when moving forward and its reduction during the reverse movement, the mass of the mixture in the pollutant decreases and increases accordingly. For the accepted conditions, its time distribution is shown in FIG. 5.

The maximum mass value is reached at stops of the Czech Republic at the O ₁ boundary (8.20 t), when all accumulated mass is discharged from the CL to the pollutant, and the minimum value (7.34 t) is dumped at the O ₂ boundary _{of the} pollutant. Taking into account the indicated regularity, the mass of the charge in the pollutant should be determined and compared with the average value of the mass in the previous cycle - during the time the PD moves from one boundary of the pollutant to the other and back.

The test results on the operation of the sinter machine AKM-312 with the parameters of the proposed method compared with the regime with parameters corresponding to the prototype and figure 3, are shown in table 2.

table 2 Options Prototype method The inventive method Productivity of sinter machine, t / h 447 456 The height of the layer of the charge, mm 480 480 Pallet speed, m / min 3.31 3.37 Temperature difference "periphery-center", ° С + (80 ÷ 160) + (50 ÷ 100) Return rate, t / h 165 152 Mass fraction of the fraction -5 mm in the bunker agglomerate,% (abs.) 17.8 17.3 Solid fuel consumption in dry weight, kg / t sinter 44.7 44.5 Mass fraction in agglomerate, FeO,% 12.47 12.30

Thus, the inventive method provides a significant improvement in the conditions of formation of the charge layer in the loading funnel, increases the uniformity and orderliness of the distribution of particle size distribution, density and fuel in the volume of the layer, the symmetrical distribution of the charge at the side walls of the loading funnel and, as a result, increases the uniformity of the sintering process in the volume layer and the width of the pallet of the agglomeration machine, increasing its productivity and yield of agglomerate.

The method can be implemented in an industrial environment using standard equipment using standard monitoring devices and a local automatic charge loading process control system.

Information sources

1. The method of agglomeration. F. Massami. Shin Nippon Seitsetsu K.K. Application 61-170524, Japan. Claim 01/22/85 No. 60-9355, publ. 08/01/86. MKI. C 22B 1/20.

2. Kavasaki M. // CURR Adv. Mater. and Proc. 1990. No. 1. P.58-65.

3. V.I. Korotich, S.S. Goncharov, V.L. Pukhov, G.I. Komornikov // Bull. QIIN World Cup. 1969. No. 17. S.71-72.

4. Production of sinter. Technology, equipment, automation. V.P. Zhilkin, D.N. Doronin. Yekaterinburg: Ural Center for PR and Advertising, 2004, 292 p.

Claims (2)

1. The method of loading the sinter charge, including controlling the charge flow supplied to the charge loading unit, loading the charge through estrus onto the conveyor belt of the shuttle dispenser, the cart of which moves between the boundaries of the loading funnel with the formation of a layer of the charge on the conveyor belt of the shuttle distributor and in the loading funnel, issuing charge from the feed hopper to the sinter machine, control the charge level in the feed hopper and the shuttle dispenser operating mode with the same conveyor belt speed it is in heat when the truck stops at the borders of the loading funnel, when moving forward (B) to the border of the loading funnel farthest from the heat and returning back (H), characterized in that the shuttle distributor is set according to the conditions:

where V _lO1 , V _lO2 - respectively, the speed of the conveyor belt of the shuttle distributor in the modes of stops at the front of the estuary and distant from it boundaries of the loading funnel forward and backward;
V _lv and V _ln - respectively, the speed of the conveyor belt of the shuttle distributor in the modes of operation forward and backward;
V _TV and V _tn - the speed of the shuttle distributor trolley in the forward and backward operation modes;
N _SLO1 and N _SLO2 - respectively, the height of the charge layer at the near and far from estrus boundaries of the loading funnel at the moment the shuttle dispenser begins to move after stops;
N _sl.s is the height of the charge layer in the center of the loading funnel at the moment of its intersection with the charge stream from the shuttle distributor. 2. The method according to claim 1, characterized in that when weighing the charge in the feed hopper, the mass of the charge is calculated as the average per cycle and its value is compared with the average weight in the previous cycle.

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