State-owned minerals processing researcher Mintek continues to remains at the forefront of research.

This research is focused on introducing technologies to enhance optimisation opportunities within the sector and extract value from products considered nothing more than waste.

Extracting valuable metals from urban waste

Mintek has initiated a strategic programme to develop competitive waste management technologies for recycling and treating urban waste to recover valuable metals in order to extend mineral resources and reduce the volume of hazardous waste in urban areas.

This article first appeared in Mining Elites in Africa 2019

A research project undertaken in 2018 explored the opportunity of recovering lead metal from electronic waste components that contain Cathode Ray Tubes (CRTs).

Electrical and electronic waste (e-waste) is a rapidly growing problem in South Africa which currently produces 360 000 t of e-waste annually.

Discarded computer monitors and television screens containing CRTs represent a major fraction of the total e-waste generated.

The glass that makes up the funnel section of the CRTs contains a significant amount of lead (~20 % Pb).

CRT glass therefore poses serious risks to human health and environmental pollution if illegally disposed of in municipal waste landfills or informally processed through unsafe recycling operations.

Mintek’s pyrometallurgy division has developed a thermal processing technology for the efficient extraction of lead from CRT funnel glass.

The process features a simple flowsheet implementing manual separation of the CRTs to generate panel and funnel glass followed by smelting of the funnel glass in a gas-fired rotary furnace to produce lead metal with a purity of 99 % Pb.

This technology has the potential to exploit CRTs as a secondary metal resource of lead while mitigating risks to human health and environmental pollution by reducing the volume of lead-bearing glass in urban areas.

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