HOUSTON—U.S. Zinc has begun an expansion project at its two domestic zinc oxide plants that will result in more capacity, equipment and employees at each site.

Phase 1 of the project will expand U.S. Zinc's oxide plant in Clarksville, Tenn., according to the company, and will conclude by the end of the year. Phase 2 will include expansion at the firm's facility in Millington, Tenn.

The company said each location will receive new equipment that will enable the use of secondary raw materials as feedstock, a key for recycling. Zinc oxide production is expected to increase by 17,000 metric tons per year after the expansions are complete.

U.S. Zinc, headquartered in Houston, manufactures, recycles and supplies zinc oxide, zinc dust, zinc metal and zinc fines. It has operations in North America, South America and Asia and is a wholly owned subsidiary of Brazilian-based Votorantim Metias, one of the world's largest zinc producers.