Critical Mineral & Material Recovery

Systems Engineering

We support technology developers turning lab chemistry and novel recovery systems into reliable, field-deployable hardware.

Johnston Engineering designs, analyzes, builds, and tests demo-scale, pilot plant, and commercial-scale systems that recover critical minerals, rare earths, and other materials from brines, black mass, tailings, red mud, waste water, and industrial process streams.

Our work reduces technical risk so your team can move forward with confidence and meet US material needs.

Schedule Consultation

Process Translation

We design systems based on your operating conditions, flow rates, chemistry and process requirements. We size solvent extraction columns, pumps, piping, manifolds, support structures, heat exchangers, and remaining system components for reliable operation.

Pilot-Ready Deployment

We deliver ready to operate systems. We integrate proper drains, vents, sampling ports, controls, instrumentation locations, and serviceability features ready for field deployment.

Harsh Materials Handling

Handle acids, bases, chlorides, and abrasive slurries with confidence. We design equipment to protect operators and extend system lifespans by selecting appropriate materials, seals, and safeguards for aggressive chemistry, materials, and wear.

System Operations We Support

Electrochemical - Our electrochemical work includes electrowinning and electrorefining skids for metal recovery, electrodialysis systems (ED/BMED, EDI, CDI/MCDI) for selective separation, and development platforms for electro-oxidation and electrocoagulation processes.

design electrolyzers from scratch and we can design skids that support electrochemical process for the above ^ processes.

Membrane & Solid/Liquid Separation - We design systems that support membrane separation technologies and membrane contactors. Our team integrates your custom system with off-the-shelf (OTS) and custom solid/liquid separation equipment such as filter presses, centrifuges, and hydrocyclones for reliable, continuous operation.

Hydrometallurgy - Our hydrometallurgical work includes ion exchange (IX) columns for adsorption and desorption, solvent extraction (SX) systems, and complete SX-EW flowsheets. We also design selective precipitation and crystallization systems and leaching equipment with integrated PLS handling and raffinate management.

Our team brings deep experience in electrochemical, membrane, and hydrometallurgical system design to help clients move from process concept to working hardware.

Thermal & Phase-Based Separation - We design systems that leverage temperature and phase changes for separation and concentration. This includes evaporation and distillation systems, crystallizers, dryers, and solvent recovery processes. Our team supports thermal integration, heat recovery, and scale-up of lab-based thermal processes into pilot-ready and commerical-ready equipment.

Engineering That Reduces Scale-Up Risk

Scaling a recovery process isn’t just about chemistry - it’s about building systems that operate reliably with aggressive fluids, abrasive slurries, and ever-changing feed streams. Our team bridges the gap between process design and mechanical reality, helping you build equipment that’s safe, maintainable, and ready for deployment.

Structural & Mechanical Integrity

Johnston Engineering performs Structural Finite Element Analysis (FEA) for pressure boundaries, vessel supports, frames, and test stands. We assess deflection, vibration, and stress under operating loads and thermal expansion. Our designs conform to sound engineering practices and relevant standards such as ASME and B31.3 where applicable, ensuring both safety and reliability for pressurized or corrosive systems.

Chemical Compatibility & Materials Selection

We are experienced in designing systems that handle acids, bases, and aggressive solutions such as HCl, H₂SO₄, NaOH, and ammonia. Our team selects wetted materials, gaskets, and fasteners for optimal corrosion resistance, utilizing PVDF, PTFE, PFA, ETFE, FRP, CPVC, and Hastelloy where appropriate. All fluid-contact components are specified for chemical duty, minimizing maintenance and maximizing equipment life.

Thermal Analysis

Our engineers use ANSYS and analytical modeling to evaluate heat generation, dissipation, and transfer across packed beds, reactors, and electrochemical cells. We design heat exchangers, cooling jackets, and insulation strategies to maintain precise thermal control for endothermic and exothermic processes. We also specialize in managing heat from high-current electrochemical systems and scaling up laboratory temperature control systems to pilot or industrial environments.

Deploy Your Material Recovery System

We help teams go from process concept to working pilot plants and commercial systems. Share your process flowsheet and scaling goals.

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