SU1643090A1 - Methods of classifying mineral raw materials - Google Patents

Description

one

(21) 4676130/03 (22) 04/11/89 (46) 04/23/1. Bul Number 15

(71) Leningrad Mining Institute. G. 8. Plekhanova

(72) A.V. Bogdanov, A.A.Smirnov and O.N.Tikhonov

(53) 622.732 (088.8)

(56) Lynch A.J. Crushing and grinding cycles. M .: Nedra, 981, p. 189.

Gudima V.I. Osyuvy automation processing plants. - No.: Nedra 1879, p. 189.

(54) METHOD FOR AUTOMATIC CLASSIFICATION OF MINERAL RAW MATERIALS IN HYDRO-CYCLONE TYPE APPARATUS

(57) The invention relates to the technology and automatic control of the process of mineral classification. The goal is to increase the efficiency of the classification process. This classification is carried out in the same type of hydrocycle on a symmetric scheme with an equal number of clean-up operations (software) and control operations (KO). Sands PO and plums TO are directed to previous ones in the technology of the operation of the classification cycle. A portion of the KO sand is separated and sent to parallel software. A portion of the drainage software is separated and sent to parallel KO cycles. The combined pitaniz of each operation of the cycle is stirred and stabilized at the inlet of each operation a water head. The modification of the classification conditions is carried out by changing the density of the variable power cycle operations and changing the costs of the separated parts of the QF sands and the discharge of the software according to the measured values. The change in the expenditures of the separated parts is corrected according to the measured value of the density of the initial power of the classification cycle. The use of the method is expedient for technology areas characterized by significant variations in the parameters of the separated pulp flow. 2 Il.

The invention relates to the technology and automatic management of the process of classification of mineral raw materials and can be used in the beneficiation plants of the wet methods of ore preparation and separation.

The aim of the invention is to increase the efficiency of the classification process. t

FIG. 1 is a flow chart of the method: FIG. 2 is a block diagram of devices and devices.

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The system implementing the proposed method (for example, two-stage classification) includes mixers 1. 2, 3, hydrocyclones 4, 5, 6, pullers 7, 8, sump-pumps 9, 10, densitometers (PR-1025) 11, 12, 13, secondary devices 14. 15, 16, regulators 17, 18, actuators (MEO) 19,20, control valves (GDG) 21,22.

It is known that symmetric and synchronized schemes for the separation of mineral raw materials, i.e. such in which the separation characteristics of all input

operations in the scheme are identical, have the property of increasing the steepness, i.e. separation purity (classification efficiency in our case) is directly proportional to each pair of added operations (cleaning and control). It is proved that in all unbalanced modes, the resulting separation characteristic of the scheme deviates more from the stepwise law of ideal separation than for the balanced mode. The separation characteristic of a hydrocyclone Јк (Ј) and the steepness of the characteristic at the separation point E (р) are determined by the expression

Јs. (p, I) 0.5 - 0.5xth (4D) 1 AH, (I)

where A V0KP2 - R 1 (p-pulps) - Vcp.

(4 OC R D) 1 h Wakr2 (RO-Rulp) (2)

where PO, p, / Epulpy are respectively a symbol of a constant particle density, density of mineral raw materials, and also pulps;

I - particle size;

D is the macrodiffusion coefficient;

h is the bed depth of the separating material in the separation zone;

R is the average radius of the hydrocyclone,

Vcp.Qncx / S is the average radial velocity of the outflow from the wall of the pulp, equal to the ratio of the volume flow of the pulp to the hydrocyclone to the lateral surface area;

VOKP. - ambient pulp rotation rate in a hydrocyclone;

Oc / 12 is the coefficient of internal friction (resistance);

th is a symbol of hyperbolic tangent.

As can be seen from expressions (1, 2), the condition for synchronization of the classification scheme in hydrocyclones requires the provision of a field. Neither of the following requirements: uniformity of applied hydrocyclones, stabilization of inlet pressure in hydrocyclone operations, as well as changes in the density and volumetric flow rate of pulp products of operations to change the initial power of the classification cycle.

The system operates as follows.

The initial pulp feeding of the classification cycle enters the mixer 1, where it mixes with the sands of the first stage of the cleaning operation and the drain of the control operation, the mixed total feed is fed by gravity into the hydrocyclone 4 of the main classification, located from mixer 1 at the height of I to create

required water pressure. The hydrocyclone 4 is drained by gravity into the sump pump 9, where it is mixed with part of the sands of the control operation (stage I and sent by the pump to mixer 2, where the mixture is further mixed and fed by gravity into the hydrocyclone 5 cleanup classification stage II, separated by height I from mixer 2 by an amount equal to

0 height difference from mixer 1 to hydrocyclone 4 of the main classification. The discharge of hydrocyclones 5 is fed by gravity into the pulp divider 7, which divides the product into two parts; ready discharge cycle classification and

5 is a circulating product, which is fed by gravity to the mixer 3, where it is mixed with the sands of the hydrocyclone 4 of the main classification. The mixed pulp product flows by gravity into the hydrocycle b (distance in height by the amount of I from mixer 3) of the control classification of stage II, the discharge of which through sump pump 10 falls into mixer 1 of the main classification, and sands into the puller 8, where the product is divided into ready-made sands of the cycle and the circulating product entering through sump-pump 9 to the clean-up operation of stage II.

The radioactive densitometer 11 continuously records the density of the total mixed feed of the main cycle classification, which corresponds to the measured density value, the signal through the secondary device 14 is fed to the input

5 adders of regulators 17,18 of the power control loops of the cleaning and monitoring operations, correcting the error signal; the circuits function in the same way as follows: radioactive density meters 12,13 continuously monitor the densities of the mixed pulp feed, respectively, of the cleaner and control cycle classification, the corresponding signals through

5, the secondary devices 15, 16 are fed to the input of the adder of the regulators 17, 18, where they are compared with the setpoint (taking into account the correction from the tracking power metering densitometer 11), with a mismatch the control

0, the signals from the output of the regulators 17, 18, respectively, arrive at the inputs of the actuators (of the MEO type) 19, 20, which change the position of the dampers of the control valves 21, 22, thereby changing

5 expenditures of the separated parts of the sands of the control operation, sent to the cleanup classification and discharge of the cleanup operation, sent to the control classification, while naturally stabilizing the densities in the cleanup and control operations occurs by changing the feed to the cleanup classification of denser sands, and in the control - less dense compared with the original power drain.

Consider the examples of synchronizing modes of the system. The pressure stabilization at the inlet of hydrocyclones 4, 5, 6 is ensured, as noted, by the constancy of the height difference between the mixes 1, 2, 3 and the corresponding micro cyclones.

The functional control of the cycle can be represented as:

-Х | (ОЙХХ.) - У (РП) + UO (ОP) | (3)

If- xj (l, Cx.) -Zi () + Zo (pk) - min,

when yo (rp) - Zo (Ok),

where xj (ЈW: x.), yi (pn), Zi (pk) are, respectively, the current signals of the density of the original feed, feed through the cleaner and control classification.

Уо (рп), уо (/ Ек) - the settings of the regulators 17,18 of the density stabilization circuits of the cleaning and control cycle operation. Thus, the overall task of managing the proposed classification cycle is to minimize the dynamic deviations of the current values of the signals of the total initial power density and the cleanup classification power from setting the cleanup operation stabilization loop, as well as the common initial power supply cycle and control power classification from the contour setting. stabilization of the control operation of the cycle, provided that the tasks of both stabilization circuits are equal.

Due to saturated circulating flows, the proposed classification cycle has a significant degree of self-leveling of disturbances at the input (by volume-mass flow rate), solid fractional composition, etc.), which ensures the monotony of change

Xj (/ EFSh), Y, (pn), Zi (pk).

the cycle time constant can be approximately expressed as (J)

T (M + Mc) / 0ex. + Osl / Oisho / cf. Ofc / l J5dn).

(four)

where M, Mz is the mass of classification material in cycle capacitances and circulating flows;

Oish, Osl. - mass costs of solid in the initial interval of the cycle and in the sink; Oc - kinematic viscosity of the medium; 1p is the separation size;

five

0

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ac - centrifugal acceleration of mineral particles in synchronous hydrocyclones.

From (4) it follows that the proposed method is most appropriately used for areas of technology characterized by significant variations in the parameters of the pulp stream to be separated.

When a low-frequency change in the density of the initial power supply of the cycle (high-frequency, as noted, self-compensated), the next density meter 11 produces a correction for the change of the error signal of the regulators 17, 18, which, through the actuators 19, 20 and the control valves 21, 22, proportionally change the error of the circulating parts of the sands and the discharge of the cycle, entering respectively the cleanup and control classifications, thereby equalizing the density of the operations of the circuit and synchronizing the circuit.

When a low-frequency change in the fractional composition of the initial power occurs, a change in the equilibrium of the densities in the cleaning and control cycle classification is recorded by the densitometers 12, 13, and as a result of the mismatch, the regulators 17, 18 produce a change in the corresponding circulating streams, synchronizing the circuit. In this case, synchronization of the main classification takes place due to a change in the circulation of sands of the cleaner cell and discharge of control cycle operations directed to the process head (Fig. 1), since they vary (g) in accordance with the separation characteristic of the output of the corresponding products.

In the case of a change in the initial power supply of the cycle in terms of density and fractional composition, at the same time, the error signals of the regulators 17.18 are formed by simultaneously changing the values of the signals Xi (Oyx), Y (pn), Z | (Osl.), In accordance with which, with the functional (3), a change of circulation directed towards the synchronization of the circuit follows the same way as the considered cases.

The size, design features of hydrocyclones, as well as inlet pressure (determined by I) are selected in accordance with the separated mineral raw materials and the task of the classification process. The adjusted parameters of the regulators, as well as the values of the settings yo (rp), Zo (rk) are adjusted during the adjustment and operation of the system.

Claims (1)

The invention The method of automatic classification of mineral raw materials in hydrocyclone-type apparatus, including a multistage classification and a change in the classification conditions, differing in that. that, in order to increase the efficiency of the process, the classification is carried out in hydrocyclones of the same type in a symmetrical pattern with an equal number of cleaning and control operations, and cleaning and cleaning sands are sent to the previous classification cycle operations, some control sands are separated and sent are in parallel cleaner . Years old - met Sands 4 2J igy Fig. / five the operations, a part of the drainage operations are separated and sent to parallel control operations of the cycle, the combined power of each operation of the cycle is mixed and stabilized at the inlet of each operation of the water head, and the classification conditions are changed by measuring the density of the variable power of the cycle operations and changing the flow rates parts of the sands of control operations and plum reheating operations in accordance with the measured values, and the change in costs of the parts to be separated is adjusted by measuring the value of the density of the original power of the classification cycle. East