Principal Engineer, Extractive Metallurgy

About Redwood Materials Redwood Materials was founded in 2017 by JB Straubel, co-founder and former CTO of Tesla, on a simple but radical idea: the critical minerals powering the energy transition already exist. They just need to come back. Today Redwood is the largest lithium-ion battery recycler in North America — recovering, refining, and redeploying critical minerals from end-of-life batteries back into the supply chain. On the energy side, Redwood has deployed the largest second-life battery project in the world, delivering power to AI data centers in months rather than years using proprietary energy architecture engineered entirely in-house. The company is profitable, the market it operates in is projected to grow 20 to 50 times over the next decade, and Redwood is the only company with the supply chain, the technology, and the operational scale to lead it. Position Summary: The position serves as Redwood's senior technical authority on extractive metallurgy across the company's recycling and refining operations. The role owns the metallurgical basis of design for how Redwood liberates, separates, and refines metals from recycled feedstocks, spanning mechanical separation of heterogeneous feeds, high-temperature processing, hydrometallurgical refining, and electrochemical upgrading of battery metals and other critical minerals. The position exercises independent judgment on methods and evaluation criteria for first-of-a-kind processes where data is incomplete, and its recommendations determine which flowsheets Redwood deploys at commercial scale. This is a strategic individual contributor role with regular interaction with Redwood's CTO and CEO, and success depends on driving innovation and plant deployment at an exceptional pace. Essential Duties and Responsibilities • Serves as Redwood's senior technical authority on extractive metallurgy, owning the metallurgical basis of design for recycling and refining flowsheets from feedstock through refined product • Leads evaluation and selection of competing flowsheet options, translating bench and pilot data into defensible recommendations for commercial deployment • Owns the metallurgical basis for intermediate and final product quality specifications, diagnosing impurity deportment across unit operations and driving issues to root cause • Directs strategy for mineral processing and mechanical separation of heterogeneous feedstocks, including comminution, liberation, classification, and physical concentration • Guides scale-up from bench through pilot to commercial operation, including mass and energy balances, equipment selection, and vendor test campaigns • Partners with Business Development to define process pathways and pricing for new feedstocks and to identify offtake markets and their value drivers • Advises operations and process engineering teams on recovery, yield, and reliability shortfalls at commissioned plants, and raises metallurgical rigor across the engineering organization through technical review and mentorship Skills, Knowledge, and Abilities • Bachelor's or advanced degree in Metallurgical Engineering, Extractive Metallurgy, Mining Engineering, Mineral Processing, Materials Science, Chemical Engineering, or a related discipline • 15+ years of experience in extractive metallurgy, mineral processing, or metals process engineering, or equivalent depth of expertise • Demonstrated ownership of deploying a flowsheet from pilot scale through commercial operation, with accountability for the plant's technical performance • Deep industrial-scale experience in pyrometallurgy or hydrometallurgy; experience across both preferred • Hands-on experience in an operating plant environment such as a smelter, refinery, or concentrator, with ability to travel to plant sites as required • Experience with comminution and physical separation of variable, heterogeneous feedstocks The position is full-time. Compensation will be commensurate with experience. We collect personal information (PI) from you in connection with your application for employment with Redwood Materials, including the following categories of PI: identifiers, personal records, professional or employment information, and inferences drawn from your PI. We collect your PI for our purposes, including performing services and operations related to your potential employment. If you have additional privacy-related questions, please contact us at privacy@redwoodmaterials.com.