When lead-acid batteries are recycled, the initial smelting stage creates a hazardous waste called slag. This slag contains toxic lead and valuable metals like iron, but it's usually dumped in landfills—posing serious environmental threats and wasting recoverable materials. Over time, the toxins can leach into soil and water, threatening ecosystems and human health. Current recycling methods are often too costly, too complex, or ineffective at safely recovering the full value of the metals.
Invention
This patent presents a safer, more efficient process to recover iron and lead from battery slag. Using standard industrial furnaces like cupola or blast furnaces, the process melts the slag under tightly controlled temperatures (below lead’s boiling point), preventing harmful lead vapor. The melted metals are separated based on their density: lead settles at the bottom, and an iron-rich alloy forms above. Both are cooled, cut, and reused—while leftover slag is safely repurposed or discarded.
Inventive
Step
Unlike previous methods that leave behind contaminants or require many steps and expensive chemicals, this process achieves over 80% lead purity and turns contaminated cast iron into a reusable alloy with less than 0.05% lead. It's designed for continuous operation, maximizes recovery, minimizes hazardous waste, and integrates reverse logistics—turning old landfill slag into valuable raw material.
Benefits
- Saves companies millions by replacing the need to buy new iron and lead.
- Cuts hazardous waste disposal by over 80%.
- Protects groundwater and soil from toxic leaching.
- Produces clean materials for reuse in battery and metalworking industries.
Broader
Impact
This process transforms an environmental liability into an economic opportunity. By making it profitable to clean up toxic slag, it supports sustainable industry practices, reduces pollution, and offers a model for large-scale waste recovery in metallurgy worldwide.