Zinc and aluminum smelter capacity in the United States has been declining for decades — and the consequences of that decline extend far beyond the metals themselves into gallium supply, sulfuric acid production, silver output, and industrial chemical availability.
Zinc smelting produces gallium as a byproduct. Aluminum smelting produces gallium through a different process route. Close the zinc and aluminum smelters, and you close the domestic gallium supply — the metal essential to directed energy weapons and advanced semiconductor devices. The connection is not obvious to anyone who doesn’t map the full industrial metabolism, which is exactly the kind of systems thinking Craig Tindale argues we have lost.
The same logic applies to sulfuric acid. Zinc and copper smelting produce sulfur dioxide as a byproduct, which is captured and converted to sulfuric acid through the contact process. Sulfuric acid is the essential reagent in copper mining and refining. Close the smelters, lose the sulfuric acid, create a dependency on imported reagents for the copper mining operations you are trying to expand domestically. The circular dependency is complete and largely invisible to policymakers.
The US aluminum smelting industry has been particularly hard hit. Primary aluminum production requires enormous quantities of electricity at prices that domestic utilities cannot consistently provide at competitive cost. The result has been a steady contraction of domestic smelting capacity, with production shifting to regions with cheaper hydroelectric power — and to China, which built aluminum smelting capacity at the scale the global market required and priced it below what Western competitors could match.
Rebuilding zinc and aluminum smelter capacity in the US is not glamorous. It is also not optional if the downstream dependencies on gallium, sulfuric acid, and silver are to be addressed. The infrastructure that nobody talks about is frequently the infrastructure that everything else depends on.