Complete Resource Recovery and Hydrogen Production from Secondary Aluminum Processing Waste Processing Waste

The secondary aluminum processing (SAP) industry in the US spends billions of dollars to send over 1 million tons of dross and salt cake waste to landfill every year. Recycling innovation for SAP waste presents a major opportunity to reduce raw material consumption and allow for significant cost savings to aluminum producers. A novel Two-Stage Alkaline Hydrometallurgical Recovery (T-SAHR) process is proposed enabling complete resource recovery and coincidental hydrogen production from SAP waste. The research in this SBIR Phase I proposal aims to accomplish previously unattainable levels of materials separation and hydrogen generation to pioneer domestic salt cake recycling. Current salt cake recycling technologies are insufficient for cost-effective recycling of SAP waste in the US, evidenced by over 95% of this material (over 1 million tons annually) going to landfill. Meanwhile, landfilling salt cake is an unsustainable option that creates a billion-dollar waste challenge for SAPs. The storage of SAP waste in landfill causes leachate, gas evolution, and potential explosion hazards (Tolaymat, T. and X. Huang, 2015). More than 100 customer interviews have shown a clear need for more cost-effective salt cake recycling options as well as an opportunity for waste products to be sold as a valuable alumina source for calcium-sulfoaluminate (CSA) cement if sufficient materials separation can be achieved. Hydrova’s proprietary T-SAHR salt cake recycling process could enable an increase in the degree of materials separation by 10x from the incumbent recycling processes while simultaneously increasing hydrogen productivity by 8x. Hydrogen generated from SAP waste can be used to dramatically increase the energy efficiency of the process. During his undergraduate work at MIT, PI Rostam Reifschneider along with co-founder Julian Davis developed an aluminum-water reaction-based method for encouraging hydrogen generation from aluminum that could enable increased hydrogen productivity during salt cake recycling. A Process Based Cost Model developed by Hydrova predicts that performing this T-SAHR process would provide up to a 30% ROI, introducing a clear economic incentive over landfill disposal. Phase I of this SBIR will de-risk the technology through characterizing parameter trade-offs, optimizing materials separation and hydrogen generation, and collaborating with SAP and CSA cement customers themselves. The attached Letters of Intent from commercial partners TST Inc., Custom Alloys, and CTS Cement demonstrate the market readiness for Hydrova’s solution and the opportunity to create a tangible economic and environmental impact.