RU65052U1 - DEVICE FOR ELECTROCHEMICAL REGENERATION OF COPPER ETCHING SOLUTIONS - Google Patents

Abstract

The utility model is used in the processes of chemical processing of metals, in particular, copper etching in the manufacture of printed circuit boards, and is intended to maintain the etching ability of the copper-containing etching solution and the utilization of dissolved copper at a constant level. The objective of the utility model is the utilization of copper by direct electrolysis of the etching solution, the automatic unloading of the copper extracted from the solution, and the possibility of using one solution without replacement in a closed cycle. The problem is solved by a device for electrochemical regeneration of copper etching solutions, containing an electrolyzer with one cathode and two anodes, a tank for storing the etching solution, a submersible pump for circulating the etching solution, a system for monitoring and controlling the pH and density of the solution, electromagnetic valves and a piping system, characterized in that the cathode of the electrolyzer is made in the form of a hollow drum immersed in the etching solution to a depth less than its radius and rotating at a speed sufficient to replenish the required concentration of copper at the cathode and electrochemically deposit it from the solution in the form of a metal powder. The device further comprises a screw device for automatically discharging recycled copper from the electrolyzer to the receiver and an ejector pump for suctioning the gas mixture from the air space of the electrolyzer and passing it through the regenerated solution.

Description

The utility model is used in the processes of chemical processing of metals, in particular, copper etching in the manufacture of printed circuit boards, and is intended to maintain the etching ability of the copper-containing etching solution and the utilization of dissolved copper at a constant level.

A device for electrochemical regeneration (1). During its operation, the copper-ammonia solution from the etching installation of the printed circuit boards is fed into the reservoir for storing the etchant with a high copper content, from which, in turn, it is fed to the electrochemical regenerator by means of a metering pump, in which the etchant is restored and copper is extracted in the form of metal .

The disadvantage of this device is the presence in the design of the electrolyzer of ion-exchange membranes having a limited service life, as well as the fact that a stationary cathode is used, for the effective operation of which, as well as for anodes, it is necessary to use circulation pumps to maintain the required copper concentration at the cathode surface, which is a necessary condition for the process of copper extraction.

The objective of the utility model is the utilization of copper by direct electrolysis of the etching solution, the automatic unloading of the copper extracted from the solution, and the possibility of using one solution without replacement in a closed cycle.

The problem is solved by a device for electrochemical regeneration of copper etching solutions, containing an electrolyzer with one cathode and two anodes, a storage tank for the etching solution, a submersible pump for circulating the etching solution, a system for monitoring and controlling the pH and density of the solution, electromagnetic valves and piping system,

characterized in that the cathode of the electrolyzer is made in the form of a hollow drum immersed in the etching solution to a depth less than its radius and rotating at a speed sufficient to replenish the required concentration of copper at the cathode and electrochemically deposit it from the solution in the form of a metal powder.

The device further comprises a screw device for automatically discharging recycled copper from the electrolyzer to the receiver and an ejector pump for suctioning the gas mixture from the air space of the electrolyzer and passing it through the regenerated solution.

Figure 1 shows the block diagram of the device and its binding to the installation of etching printed circuit boards, where:

1 - etching installation, 2 - reserve capacity, 3 - ejector pump, 4, 5 - electromagnetic valve, 6 - electrolyzer, 7 - cathode, 8 - anodes.

In accordance with the scheme, the etching solution from the etching unit 1 enters the reserve tank 2, from which it is continuously circulated through the circuit using a submersible pump (not shown): tank 2, pipeline, ejector pump 3, pipeline, etching installation 1. Tank 2 is equipped devices for monitoring and controlling the pH and density of the etching solution (not shown). When the pH drops below a predetermined value, the solenoid valve 4 is opened and gaseous ammonia is supplied to the continuous circuit of the etching solution through the ejector pump 3 until the pH reaches the desired value.

When the etching solution density increases to the maximum preset value, the electromagnetic valve 5 opens and the etched copper solution is supplied to the electrolyzer 6. Simultaneously, the electrodes, cathode 7 and anodes 8 are supplied with voltage from a direct current source (not shown) and the cathode rotation system (not shown).

The cathode 7 is made in the form of a hollow drum made of stainless steel immersed in the etching solution to a depth of less than a radius. The anodes are stationary and, depending on the composition of the etching solution, can be made of various materials.

To control the temperature, the electrolyzer is equipped with a cooling water supply system.

With the passage of current at the cathode, copper is deposited, due to which the density of the solution decreases and its etching ability is restored.

The rotation of the cathode is carried out at a speed that ensures replenishment at the cathode of the required copper concentration for electrochemical deposition of it at a set current value in the form of a metal powder. Copper powder using a scraper 9 is removed from the cathode and poured into the trough of a screw device (not shown), with which it is discharged from the electrolyzer 6 into a receiver (not shown).

At the anode, with the passage of current, the etching properties of the solution are restored by oxidizing the monovalent copper formed in the solution during etching of the printed circuit boards to divalent. Along with this, oxygen is released at the anode, which, together with other gases (ammonia, nitrogen), is sucked out of the electrolyzer using the ejector pump 3 and, when passing through the pickling solution, it also oxidizes monovalent copper to divalent copper, regenerating the solution. The copper-depleted solution from the electrolyzer 6 is gravity drained into the etching installation of the printed circuit boards and reduces the concentration of copper in the working solution. The process in the cell continues until the concentration of copper in the pickling solution (otherwise, the density of the solution) reaches a predetermined lower limit.

All these actions are performed automatically and are reflected on the panel of the control cabinet (not shown), which contains a control unit, a rectifier, indicators of the temperature of the solution in the electrolyzer, pH values and electrolysis current, as well as light indicators for monitoring the process and displaying faults.

Productivity of the device for electrochemical regeneration of copper etching solutions on a rotating electrode up to 2 kg of copper per hour.

The device can be connected to any etching plant. The use of the described utility model made it possible to exclude discharges of a copper-containing solution to treatment facilities, to fully automate the regeneration process, and to improve working conditions.

References:

1. US patent No. 4545877, 1985

Claims (2)

1. A device for the electrochemical regeneration of etching solutions of copper, containing an electrolyzer with one cathode and two anodes, a storage tank for the etching solution, a submersible pump for circulating the etching solution, a system for monitoring and controlling the pH and density of the solution, electromagnetic valves and a piping system, characterized in that the cathode of the electrolyzer is made in the form of a hollow drum immersed in the etching solution to a depth less than its radius and rotating at a speed sufficient to make up for the cathode rebuemoy concentrations and electrochemical deposition of copper from solution in the form of metal powder. 2. The device according to claim 1, characterized in that it further comprises a screw device for automatically discharging recycled copper from the electrolyzer to the receiver and an ejector pump for suctioning the gas mixture from the air space of the electrolyzer and passing it through the regenerated solution.