Recovery of gold from printed circuit boards

GOLD RECOVERY OF PRINTED CIRCUIT BOARDS FROM OBSOLETE COMPUTERS THROUGH THE BIOHYDRO-METALLURGICAL PROCESS

Printed circuit boards, platforms on which components such as semiconductor chips and capacitors are mounted, provide electrical interconnections between components and are found in almost all electronic equipment, being generally composed of polymers, ceramics and metals, which makes its processing difficult due to its heterogeneity.

The presence of base metals and precious metals such as gold, stimulate studies regarding their recycling. Biohydrometallurgy, that is, the use of bacteria capable of mobilizing metals from ores with low metallic contents, is a promising alternative that has been applied in the recovery of metals of interest. This project proposes to study the recycling of printed circuit boards from obsolete computers and it is expected as the main result the definition of operations that enable gold recovery.

For that, mechanical processes using unit operations of ore treatment will be applied for the separation of the metallic, plastic and ceramic fractions. The material will be subjected to bacterial bioleaching tests. These tests will be conducted with mesophilic microorganisms, at 34ºC.

During bacterial leaching, the main harmful components in gold metallurgy will therefore be leached into the liquid phase. In the fraction
the gold will be concentrated with a low concentration of non-ferrous metals, polymers and ceramics. Gold recovery will be carried out according to traditional gold metallurgy with the cyanidation process.