While most primary zinc smelters continue to use the old and less-efficient ball-mill process to treat their casthouse dross, some around the world have switched to Pyrotek’s zinc-recovery system. They have discovered that the change reduced energy consumption and improved zinc recovery rates, allowing them to remain strong with increasing global competition.
Ball-mill processing, or grinding and sieving, can degrade air quality because of the particulate matter produced. Along with the environmental impact, ball-mill processing requires substantial energy consumption.
A significant volume of metallic zinc remains in fine particle dross and needs to be continually processed in the roaster, driving up energy consumption and ultimately leading to lost zinc sales. Large stockpiles of raw dross can often be stored at plant sites, further impacting the environment at the site.
With the acquisition of an MZR-2000 zinc-recovery unit, with a capacity of 2000 kilograms (4400 pounds), plants could decommission their dross mills. This alone removes a significant environmental hazard in the process. These zinc-recovery systems can keep up with a site’s dross generation, eliminating the stockpiling of dross and any related cleanup issues.
The average zinc recovery rate for an MZR-2000 is approximately 60 percent. By contrast, the grinding and screening of the ball-mill process delivers approximately 35 percent recovery. A lower recovery rate means more material is sent back through the roaster.
If Pyrotek’s zinc-recovery system can increase a casthouse’s plant capacity by only 1 percent, it could result in millions of dollars in increased sales output when prices reach more than USD$3000 per tonne on the London Metal Exchange.
Pyrotek also offers zinc-recovery systems with capacities of 750 kilograms (1650 pounds) and 1500 kilograms (3300 pounds). Pyrotek’s global network of application engineers can work with plants on-site to find the right system for processing needs.