The RETEC and AUROCLAIM systems

Description of plant

These systems have been developed for the electrolytic recovery of metal compounds in solution. Their very simple operation is based on the same principle as the electrolyzers used for electroplating of metals.

Under the influence of the low-voltage current (3 - ­5V) applied between the electrodes, the metal cations, present in the solution to be treated are reduced and deposited as metal in the pores of foamed cathodes. The solution to be treated passes through a series of cathodes, providing a large effective surface. Hence the probability of contact between the metal in solution and the cathodes is considerably increased. Metallic ions are thus removed from the solution which may be returned either to the rinsing bath or to the purification plant. The solution to be treated can be circulated several times through the cell in order to achieve the required percentage of metal recovery.

There are several types of RETEC cells for the recovery of non-precious metals, which have a number of cathodes ranging between 6 and 50. The choice of the cell type depends mainly on parameters such as the flow-rate, treatment time, initial and final concentration of metal to be recovered.

The AUROCLAIM cells operate in the same way as the RETEC cells and are mainly used for the recovery of precious metals and their alloys; due to the reduced size of their cathodes they effectively avoid having too much metal stored in the cell.

Equipment

The RETEC and AUROCLAIM cells are delivered fully equipped and ready for connection. A simple system allows self-priming of the pump. RETEC cells are provided with bath agitation by means of forced air to allow optimum recovery of metal. With porous plates located at the inlet and outlet of the cell, uniform electrolyte flow in the cell is ensured with the retention of solution particles larger than 300 microns.

The electric power supply of the cells is controlled by a rectifier whose power is adapted to the cell size. The current consumption is low.

The Cathode/Anode

The cathode is the heart of the cell and consists of metal foam with a very large effective surface (approximately 15 times the geometric area). It enables the metal ions present in the solution to be effectively eliminated, even at a very low concentration (a few ppm).

When fully loaded, the cathode can retain amounts of metals up to 100 times its initial weight (several kilos). When one of the cell cathodes is charged with metal, it can easily be replaced without interrupting the operation of the electrolyzer. The metallized cathode may either be sold for its metal value or used as an anode in a recycling unit.

The Anode consists of a titanium mesh covered with a noble-metal catalyst to ensure its high chemical and electrochemical stability. It is designed to generate oxygen in aggressive media.

The anodes are connected to the anode bus bar via a durable snap connection and may be readily withdrawn from the RETEC cell for cleaning.