Sr. Pyrometallurgical Process Engineer | San Francisco, CA | Houston, TX

Job Description

Company: Mariana Minerals
Location: San Francisco, California, United States / Houston, Texas, United States (On-site)
Category: Mineral Processing and Metallurgy
Job Type: Full-time
Experience Level: Senior-Level
Salary: $130,000 – $160,000 USD / year
Compensation: Offers equity

Job Summary
Mariana Minerals is seeking a Senior Pyrometallurgical Process Engineer to support the development and deployment of high-temperature refining and thermal processing systems for critical minerals.

This role focuses on designing, modeling, scaling, commissioning, and optimizing pyrometallurgical unit operations, while supporting software-enabled capital project execution and automated plant optimization.

Key Responsibilities

• Lead pyrometallurgical process scopes from concept development through detailed engineering, procurement, fabrication, installation, commissioning, ramp-up, and handover to operations
• Develop heat and material balances for high-temperature process trains
• Support processes including drying, calcination, roasting, reduction, smelting, converting, slag cleaning, refining, and off-gas treatment
• Design and validate thermal process flowsheets, PFDs, and P&IDs for pyrometallurgical circuits
• Build thermodynamic and kinetic models for high-temperature reactors and furnaces
• Support scale-up and commercial deployment of rotary kilns, calciners, electric arc furnaces, submerged arc furnaces, reverberatory furnaces, and flash smelters
• Model and optimize phase equilibria, slag chemistry, metal recovery, refractory performance, and energy efficiency
• Define specifications and operating envelopes for high-temperature process equipment, burners, power systems, refractory linings, and gas-handling systems
• Identify and implement process improvements to maximize metal recovery, reduce energy consumption, control emissions, and improve furnace stability
• Collaborate with R&D, laboratory teams, and pilot-plant engineers to translate bench and pilot findings into commercial pyrometallurgical designs
• Work with environmental and controls teams to design and optimize off-gas handling systems
• Partner with software and machine learning teams to automate process engineering workflows and develop advanced control, optimization, and digital twin models

Qualifications

• Strong foundation in chemical engineering, metallurgical engineering, process engineering, or a related field
• Strong understanding of engineering fundamentals and ability to apply them to complex pyrometallurgical systems
• Experience with pyrometallurgical mineral processing or metal refining
• Experience with high-temperature process equipment, reactors, furnaces, and thermal processing systems
• Experience with equipment engineering, design, troubleshooting, evaluation, and optimization
• Experience with brownfield modifications and upgrades of process equipment is a plus
• Experience with greenfield design of mineral processing or metallurgical unit operations is a plus
• Background in large-scale mining, critical minerals processing, battery materials production, industrial chemical manufacturing, or EPC/EPCM environments preferred
• Ability to collaborate with R&D, pilot plant, environmental, controls, software, and machine learning teams
• Strong problem-solving skills and ability to work in fast-paced technical environments

What We Can Offer You

• Opportunity to help build first-of-a-kind critical minerals refining systems
• Work on technologies supporting modern energy, AI, and defense applications
• Autonomy to make meaningful technical decisions
• Collaboration with engineering, R&D, environmental, controls, software, and machine learning teams
• Opportunity to contribute to automation, digital twins, advanced controls, and plant optimization
• Mission-driven culture focused on ownership, optimization, automation, and collaboration
• Competitive base salary and equity opportunity

Why This Role Matters
This role is important because pyrometallurgical process engineering is essential for scaling critical minerals refining, improving metal recovery, reducing energy use, and building reliable high-temperature processing systems.

As a Senior Pyrometallurgical Process Engineer, you will help turn lab and pilot-scale work into commercial mineral refining operations that support a more resilient and responsible critical minerals supply chain.

Apply
👉 Apply online: https://jobs.ashbyhq.com/marianaminerals/0f87c899-7bf3-425a-b6d9-6a973f4e62f2

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