Senior Process Development Engineer Jobs in Wilmington, MA

Phoenix Tailings is a rapidly growing clean mining and metals production startup dedicated to sustainable and economic critical metals production. Our mission is to be the world’s first fully clean mining and metals production company—producing the resources required to power the technology of today and tomorrow.

At Phoenix, we’re building more than technology—we’re building the future supply chain for critical and rare earth metals. This work matters. It demands urgency, rigor, and creativity. You’ll join a team that values ownership, technical excellence, and the courage to challenge legacy approaches to mining and metals production.

• You are only crazy if you are wrong, it’s ok to be wrong
• Lead with Compassion
• Be Resourceful
• Listen
• Hustle

Phoenix Tailings is looking for a Senior Process Engineer- Hydrometallurgist to lead hands-on process development, optimization, and scale-up of hydrometallurgical systems for critical and rare earth metals production. This role is ideal for someone with deep technical experience in wet chemistry, aqueous processing, leaching, precipitation, separation, purification, and pilot-scale development who wants to build real-world industrial processes, not just model them.

This position will play a key role in translating laboratory results into scalable process designs that support Phoenix Tailings’ transition from R&D to commercial deployment. You will work closely with R&D, engineering, and pilot operations teams to design experiments, troubleshoot complex process challenges, develop operating parameters, and guide junior engineers and scientists.

• Lead the design, execution, and analysis of hydrometallurgical experiments involving leaching, purification,precipitation,precipitation, solid-liquid separation, solvent extraction, and related critical metals processes
• Develop and optimize process conditions for laboratory, bench-scale, and pilot-scale hydrometallurgical systems
• Translate experimental results into process flow diagrams, mass balances, operating windows, equipment specifications, and scale-up recommendations
• Provide technical leadership for wet chemistry work, including solution chemistry, acid-base chemistry, pH control, filtration, precipitation, reagent selection, and process troubleshooting
• Support equipment sizing and selection for reactors, filtration systems, thickeners, mixer-settlers, tanks, pumps, and other hydrometallurgical process equipment
• Lead root-cause analysis and troubleshooting for process performance issues, including recovery losses, impurity behavior, phase separation challenges, and process instability
• Collaborate with engineering, R&D, and operations teams to develop pilot-scale test plans, operating procedures, and process control strategies
• Mentor junior engineers, scientists, and technicians in experimental design, lab execution, safety practices, data interpretation, and technical documentation
• Maintain clear technical records and prepare reports, presentations, and recommendations for internal design reviews and leadership discussions
• Support the scale-up of Phoenix Tailings’ critical metals production processes from R&D through commercial deployment

• Bachelor’s, Master’s, or PhD in Chemical Engineering, Metallurgical Engineering, Materials Science, Chemistry, or a related technical discipline
• 5+ years of experience in hydrometallurgy, wet chemistry, chemical process development, mineral processing, metals refining, or related chemically intensive systems
• Strong hands-on experience with hydrometallurgical unit operations, including leaching, precipitation, filtration, solid-liquid separation, solvent extraction, purification, and crystallization
• Demonstrated experience translating laboratory or bench-scale data into pilot-scale or commercial process development decisions
• Strong understanding of aqueous chemistry, solution speciation, acid-base chemistry, impurity control, reagent behavior, and process optimization
• Experience developing mass balances, process flow diagrams, experimental plans, technical reports, and operating procedures
• Experience mentoring junior technical team members or leading technical workstreams in a laboratory, pilot, or industrial environment

This pay range reflects best estimate for the total cash compensation which includes salary + discretionary bonus for this role. Total package may vary based on experience and qualifications.

Pay Range: $120,000- $190,000 total cash compensation plus equity

• Healthcare: 100% Medical, dental, and vision coverage for employee.
• Stock Options: Ownership in a fast-growing venture-backed company.
• Time Off: Unlimited PTO.
• Learning: Learning and development opportunities to grow your skills and career.

At Phoenix Tailings, we have an open culture that values learning, and we are looking to grow the team with enthusiastic individuals who share our vision of sustainable mining.

Phoenix Tailings, Inc. is an Equal Opportunity Employer, and we value diversity at all levels. All qualified candidates will receive consideration for employment without regard to race, color, religion, sex (including gender identity, sexual orientation, and pregnancy), national origin, age, disability or genetic information, or any other applicable protected characteristics, and these characteristics will not be a factor for consideration of any work-related decisions (including but not limited to hiring, firing, compensation, and discipline).