June 05, 2020

Refractory Solutions for Copper Melting

Copper is one of the most essential resources for modern society. It has been widely implemented in architecture and infrastructure for centuries, owing to its low corrosivity. Yet its unparalleled electrical conductivity has become the most important facet of copper alloys since electrification became widespread and commonplace.  
Though the likes of graphene and silicon are making headlines for their potential to revolutionize the digital era, copper remains one of the most integral materials of our time, forming the basis of virtually every electronic system in the form of wiring and key electrical elements.

Yet there is a cost to the growing demand for copper, both in virgin and recycled forms. In this article, Saint-Gobain explores how innovative refractory solutions are paving the way to more efficient processes in the copper industry.

The Cost of Copper Melting

Primary and secondary copper production are subsequently enormous contributors to the global economy. Yet, there is a tangible environmental cost to copper refining. Saint-Gobain leads the market in high-performance refractory solutions geared towards a sustainable future in critical industries. We offer a choice of finely-tailored refractory solutions for innovative copper melting systems, such as copper shafts and holding furnaces.

What is a Shaft Furnace?

Shaft furnaces operate at temperatures around 1200 °C and may be even hotter around the burners and at the tap hole.
Shaft furnaces for copper melting were developed decades ago but have only recently reached technological maturity. They were developed for the effective and efficient melting of secondary copper products of varying quality (anodes, cathodes, high-grade scrap, etc.), using a continuous method with the highest possible thermal efficiency.

A typical shaft furnace comprises a cylindrical, vertical holding chamber with a tap hole at the bottom and a series of natural gas burners dispersed radially above the tap. Base metals are fed into the top of the furnace where they are preheated by exhaust gas from the burners, before descending through the hot zone, melting, and dispensing through the tap hole.

Temperatures in a typical shaft furnace can routinely exceed 1,200°C, particularly near the burners and tap hole. This demands high-performance refractory solutions that can perform in demanding reducing environments.

Refractory Solutions for Shaft Furnaces

At Saint-Gobain, we always strive to deliver the perfect refractory solutions per customer specifications. In copper melting shaft furnaces, this means taking into consideration both thermal demands and unique geometries, but also the chemical aggressiveness of molten copper with varying chemical compositions. Our latest refractory solution for copper shaft furnaces falls under the Cryston® line; a tailormade range of refractory bricks for challenging hot face environments.

Cryston® CU is a copper-resistant refractory based on nitride or oxy-nitride bonded silicon carbide (SiC), It exceeds conventional nitride and clay-bonded SiC refractory solutions in secondary copper production owing to its superior chemical resistance and outstanding resistance to oxidation. Combined with superb all-round mechanical characteristics, Cryston® CU is the perfect refractory solution for hot face brick work in shaft furnaces.

By engineering high-performance refractory solutions for critical industries, we aim to promote greater efficiency and cleaner processes across the broadest possible spectrum of working environments. This yields a range of tangible benefits, from greater throughput to reduced waste, providing all-round improvements to profitability and sustainability. If you would like to learn more about how Saint-Gobain’s are used in copper melting, simply contact a member of the team today.