Principal Process Engineer About Cocoon : Cocoon is creating a low-carbon cement substitute for the builders of tomorrow. Our patent-pending process upcycles by-products from steel manufacture into a cement alternative (also known as a supplementary cementitious material or SCM). We are on a mission to make steel greener and cement cleaner. In the next 40 years, we will witness the construction of double the amount of infrastructure as there is in the world today, equivalent to a new Manhattan every month. Much of this infrastructure is crucial to the energy transition, catering to migrating populations, and achieving sustainable development goals. Steel and cement are integral to this construction, yet they contribute 15% of global emissions. Cocoon is committed to addressing the climate emergency by decarbonizing these crucial industries, paving the way for a better future for all. Our core technology involves manipulating molten steel slag to produce desired cementitious properties. We are seeking an experienced principal process engineer to lead our scaleup and deployment activities as we move towards our first TRL6 deployment on an active steel plant in Q2 2025 and subsequent journey to TRL 8 and beyond. We are a small but formidable team, backed by world-class and global investors in climate, hardware and industrial decarbonisation. Responsibilities: Responsible for the technical definition, development and delivery of a commercial scale slag activation process for creating Cocoon’s products Lead the deployment of a TRL6 demonstration on a US steel plant in Q2 25, managing a successful setup, operation and teardown of the system and delivering multiple tonnes of material suitable for concrete use cases Lead the design of a pilot 12ktpa slag processing system for deployment commencing 2026 Identify, appoint and manage relationships with key stakeholders including EPC partners and steel plants to support delivery of both TRL6 demonstrator and pilot Review existing technology readiness and input into process R&D strategy About You: We are seeking individuals to join Cocoon who are 'hands-on' engineers capable of wearing multiple hats, bridging the gap between an in-depth understanding of the physics of our technology and the industrial engineering required to deliver it at scale. The ideal candidate will be an experienced process engineer with a background in scaling materials processing technologies to TRL8, ideally within pyrometallurgy, mineral processing or relevant adjacent industry. Unafraid of challenges, you will be empowered by the team to lead a critical workstream in the scale-up of our technology as we look to demonstrate commercial and technical viability of our process at industrial scale. If you possess the following qualifications/qualities, we would love to hear from you: 10 yrs Industry experience in chemical/process engineering; including process design, hot cold commissioning, project/construction management Experience working in pyrometallurgical processes (steel, copper, aluminium) or mineral processing Experience scaling and integrating novel processes/technologies into already live processes Willingness to work in a fast-paced and dynamic startup environment Bonuses: Experience working in the US Experience working in/with startups Knowledge of cement and concrete production Knowledge of refractory engineering Experience managing material transport and logistics Join us on our exciting journey as we collaborate to shape the future of our company and make a meaningful impact in addressing the climate crisis. How We Work: As a company building hardware we require the team to be in our London HQ the vast majority of time. For some roles, remote working may make sense 1-2 days a week and this is something that can be discussed during the application process. We will always try to accommodate alternative working hours to suit individuals - talk to us Compensation: Highly competitive salary, plus stock options Relocation financial support may be discussed at the offer stage if relocation is required Cocoon is an equal opportunities employer. We embrace diversity as a core value and commit to providing equal opportunities for all employees, job applicants, clients, and customers, irrespective of race, ethnicity, gender, sexual orientation, religion, age, disability, or any other protected characteristic. We regularly review our policies, provide training, and encourage open dialogue to ensure a supportive and inclusive workplace for all.