ABOUT US tozero is Europe’s leading deep-tech startup specializing in the recycling of lithium-ion batteries. Committed to accelerating decarbonization and transforming the material life cycle, we’re actively crafting sustainable recycling solutions for a cleaner and more innovative future. WHAT WE'RE LOOKING FOR We are looking for a Senior Process Engineer to take a leading technical role in the design, scale-up, commissioning and ramp up of our battery recycling processes. This role sits at the intersection of technology development, process engineering, and industrial scale-up. You will translate experimental and operational data into robust process designs, challenge engineering assumptions, and ensure that our future plants are built on solid fundamentals. Your focus will be on the processes that matter most to our technology — graphite and lithium extraction. By working closely with R&D, Operations and external engineering partners, you will actively lead and engage in activities associated with: a) engineering design; b) commissioning and ramp up; c) process development. We are looking for someone who is comfortable working in a production environment, but who can also take a step back and understand what the data is telling us, and engineer the process we need at different scales. WHAT YOU CAN EXPECT Must Have's: 1. Future Plant Design & Scale-up ● Own key process design activities for our next-generation plants. ● Develop and review PFDs, P&IDs, mass and energy balances, process descriptions and equipment specifications for future capacity expansions. ● Translate pilot and industrial operating data into reliable engineering design criteria and scale-up assumptions. ● Perform process calculations and equipment sizing to ensure our future plants are designed based on validated engineering data rather than theoretical assumptions alone. 2. Targeted Process Expertise & Optimization ● Become a technical reference for some of our most critical process steps. ● Apply strong chemical engineering fundamentals to the optimization of graphite and lithium extraction and post-processing. ● Identify the parameters controlling yield, purity and process stability and translate these insights into concrete process improvements. ● Work closely with R&D and Operations while maintaining a strong focus on process performance and technology development rather than daily troubleshooting. 3. Data Analysis & Process Modeling ● Turn plant data into engineering decisions. ● Evaluate operational and experimental data, build and validate mass balances and process models, and identify gaps between expected and actual process performance. ● Define what data needs to be collected to support future scale-up decisions. ● Technically guide data analysts and other engineering functions to ensure that models and analytics remain grounded in physical and chemical reality. ● Translate analysis into clear recommendations for process upgrades and future plant designs. 4. Commissioning & Process Validation ● Make sure what we designed actually works. ● Participate in FATs/SATs, commissioning activities and process performance validation for new equipment and plant expansions. ● Develop acceptance and process validation criteria based on the original design intent. ● Evaluate commissioning and operational data to confirm that installed systems achieve their calculated performance targets. ● Work closely with Operations during handover while ensuring clear ownership transfers once the process meets its design criteria. 5. Operational Readiness, Process Safety & SOPs ● Design processes that can be operated safely and consistently. ● Translate process design and engineering intent into clear Standard Operating Procedures (SOPs), operating envelopes and process documentation. ● Participate actively in HAZOPs, LOPAs, and other process safety reviews, ensuring that process risks are identified and addressed during design rather than after installation. ● Support Operations in understanding the design basis and critical process parameters of newly commissioned systems. Nice-to-have's: Vendor & EPC Coordination ● Represent tozero's process requirements with external engineering partners and equipment suppliers. ● Prepare and review technical specifications, vendor proposals and engineering documentation. ● Challenge unsupported assumptions, identify over-engineered solutions and ensure equipment is correctly sized for our process. ● Support technical bid evaluations and equipment selection, balancing process performance, CAPEX, operability and scalability. ● Act as a strong technical counterpart to EPCs, engineering contractors and equipment vendors throughout project execution. Your profile You have a strong chemical/process engineering foundation and enjoy solving technically complex problems with a combination of first-principles engineering and real plant data. ● Degree in Chemical Engineering, Process Engineering, Metallurgical Engineering or a related technical field. ● Ideally 5+ years of experience in process engineering within the chemical, hydrometallurgy, battery, mining, minerals, recycling or related process industries; specific expertise in graphite and lithium extraction and post-processing is highly preferred. ● Strong experience with process design and scale-up, including PFDs, P&IDs, mass/energy balances and equipment sizing. ● Comfortable working with industrial datasets and translating operational data into engineering models and decisions. ● Experience with solid-liquid separation, precipitation, flotation, hydrometallurgy or mineral processing is highly valuable. ● Able to critically review vendor proposals and confidently challenge technical assumptions. ● Strong experience supporting commissioning and process validation of industrial equipment or plants. ● Familiarity with process safety methodologies such as HAZOP and LOPA. ● Comfortable moving between detailed calculations, engineering documentation and the actual plant. ● Strong communicator who can work effectively across R&D, Engineering, Operations, suppliers and EPC partners. ● Fluent English; German is a plus. Why us? Our technology is moving from first-of-a-kind industrial operations toward increasingly larger and more standardized plants. The Senior Process Engineer will help us make that transition successfully: turning what we learn from today's plant into the engineering basis for tomorrow's plants while supporting commissioning and ramping up efforts. You will directly influence process performance, equipment selection, CAPEX and the technical architecture of our future facilities — helping ensure that every new scale is safer, simpler, more efficient and better engineered than the one before it.

Senior Process Engieer @ Tozero

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