SU1392145A1 - Apparatus for automatic control of process of electrolytic extraction of silver from used fixing solutions - Google Patents

Abstract

The invention relates to the field of devices for the automatic control of the process of electrolytic extraction of sulfur from the used fixing solutions. Iso goal; Breasts - an increase in the degree of silver extraction. The comparator 6 is supplied via resistors with the voltage from the measuring brush 10 and with the auxiliary electrode 4. The voltage from the output of the comparator 10 is fed to one of the inputs of the comparator 7, to the second input of which the reference voltage is applied. The error signal through the comparator 8, to the second input of which the base voltage is applied, is fed to the generator 9 of the current, which changes the magnitude of the electrolysis current. I (L

Description

The invention relates to devices for the electrolytic extraction of silver from aqueous solutions of its salts, in particular to the electrolytic regeneration of silver from used fixing solutions and silver containing wash water, and is intended for enterprises producing chemical-photographic processing of films.

The purpose of the invention is to increase the degree of extraction of silver.

The drawing shows a diagram of the device.

The device consists of an electrolyzer 1 containing a steel cylindrical rotating cathode 2. The electrolyzer also contains graphite anodes 3 and an additional electrode 4 (silver chloride). The cathode 2, the anodes 3 and the additional electrode 4 are connected to the control device 5. The control device 5 contains an adder made on a comparator 6 and resistors R, and R _? , an amplifier made on two comparators 7 and 8 and a current generator 9. Two brushes 10 and 11 are installed on cathode 2, one is measuring, serving: to pick up a signal about the potential of the cathode, the second - current-carrying, serving to control the electrolysis current. A reference voltage source U _on (not shown in the drawing) is connected to one of the inputs of the comparator 7, and a base voltage ( ₀ ) is connected to one of the inputs of the comparator 8 (base) and _0. '

The adder resistors R _t and R _{2 are} connected to the two inputs of the comparator 6. The measuring brush 10 of the cathode 2 and the additional electrode 4 are connected to the resistors R, and Rj, respectively. The output of the comparator 6 is connected to the input of the comparator 7, the output of which is connected to the input of the comparator 8. The output of the comparator 8 is connected to the input of the current generator 9, the output of which is connected to the collector brush 11 of the cathode 2.

The device operates as follows.

Before turning on the device, two independent stabilized voltages are supplied to the amplifier comparators 7 and 8: U _o , the value of which sets the basic value of the electrolysis current Ij, and And _op , the value of which sets the potential value U _K , =. and _ea - U _Ka . When the device is turned on from the current generator 9, the electrolysis current 1 ₅ flows to the current collector brush 11 of cathode 2, this leads to the formation of signals U _9Q and U _{gc (} . At the output of comparator 6, the arithmetic sum of these potentials is converted to potential U _k3 and fed to the input comparator 7, where the potentials U _ke and U _{Qn are} compared.The result of the comparison in the form of the mismatch potential tAUp = U _op - Ts _ke goes to the input of the comparator 8, where it is compared with U _d . Thus, the total control potential is generated at the output of the comparator 8 resolved popping system apparatus of autoregulation respect to two independent stable parameters U _dn and U _o, namely _{U = U o (± & Up} ). The magnitude of the signal supplied to the input of the controlled oscillator 9, the current will alter the value of the electrolysis current. If after switching 'device U _k3 = U _on , then ± & and _p = 0 and the electrolysis current will be equal in the case of U _k3 / U _on there is a mismatch signal tbUp / 0 and the electrolysis current increases (decreases) with respect to the following. With an increase (decrease) in the arithmetic sum of potentials U _Kg = and _ea - U _{kq, the} controlled current generator 9 will decrease (increase) the magnitude of the electrolysis current. The interaction between the elements of the device is selected in such a way that when changing the silver concentration ·. during operation, the device’s automatic control system by means of tracking ensures stabilization of one of the internal parameters of electrolyzer 1 — potential and _NE .

The introduction of two independent voltage sources U _Qn and ϋ _ό and the introduction of two signals, U _kq h U _3q, into the _adder provides a high speed of the device to change the input disturbing influences and the ability to extract silver from the fixing solution to small concentrations <0.05 g / l. The presence of two independent sources ,, U _{d (1 0} hU allows if necessary to expand the motion device system of autoregulation by the problem of different values changing laws and U U _o, as a function of additional input perturbing vozdeyst s.

Example. A device for automatically controlling the process of silver electrolytic regeneration from the used fixing solutions on the industrial electrolysis bath RES-1 with two rotating cylindrical cathodes was fabricated and tested; additionally on rotating ca-. Special measuring brushes (in addition to current-conducting) are installed in the cathode to remove the signal about the cathode potential.

As a result of the tests, it was found that the device allows automatic control of 2Q of the electrolysis process to a residual concentration of silver in the fixing solution of 0.01 g / l.

Claims (1)

The claims 25 A device for automatically controlling the process of electrolytic extraction of silver from used fixing solutions mainly in an electrolyzer with ¹ steel cathode, graphite anodes and an additional electrode placed between the cathode and one of the anodes, containing a current generator, a reference voltage source, two resistors, one of which is connected to an additional electrode, characterized in that, in order to increase the degree of silver extraction, it is equipped with three comparators, a source of base voltage, By the way, the cathode is made in the form of a cylinder with the possibility of rotation, the first input of the first comparator is connected to the first resistor, the second input of the first comparator is connected to the cathode measuring brush through the second resistor, the output of the first comparator is connected to the current generator through the second and third comparators, the output of which is connected to the current supply with a cathode brush, the second input of the second comparator is connected to a reference voltage source, the second input of the third comparator is connected to a base voltage source.