Techno-economic analysis (TEA) for rare earth processing

What TEA actually is

A techno-economic analysis (TEA) is a structured model that takes a process design, the unit operations, mass and energy balances, reagent consumption and recoveries, and converts it into a financial picture: how much it costs to build, how much it costs to run, and what it is worth. It sits between two worlds. On the technical side it depends on flowsheets, bench and pilot data, and equipment sizing. On the economic side it depends on commodity prices, discount rates and financing assumptions. TEA is the bridge that lets you compare an elegant chemistry against an ugly one on the only basis that ultimately matters at industrial scale: cost per kilogram of separated product at a given purity.

For rare earth elements (REE) this matters more than in most industries. The value chain is long, mining, beneficiation, cracking and leaching, separation, and reduction to metal, and the economics are dominated by a handful of stages where reagent intensity, energy use and recovery losses compound. A route can be chemically valid and still be uninvestable. TEA is how that gets caught early.

The metrics that decide projects

Most TEAs converge on the same core outputs. Understanding what each one captures is the difference between reading a model and being persuaded by it.

CAPEX, capital expenditure

The one-time cost to build the plant: equipment, installation, buildings, engineering and contingency. Usually estimated from scaled equipment costs (the “factored” or Lang-factor method) and reported with an accuracy class (e.g. AACE Class 5 for a scoping study, ±50%, down to Class 1 for a defined design).

OPEX, operating expenditure

The recurring cost to run the plant per year or per tonne: reagents, energy, labour, maintenance, waste handling. In REE hydrometallurgy and separation, reagents and energy frequently dominate OPEX, which is why recovery and reagent recycling carry outsized economic weight.

NPV, net present value

The sum of all future cash flows discounted back to today. A positive NPV means the project earns more than the discount rate demands. It is the single headline number most investment decisions hang on.

IRR, internal rate of return

The discount rate at which NPV equals zero, effectively the project’s annualised return. Compared against a hurdle rate (the minimum acceptable return) to judge whether capital is better deployed here or elsewhere.

Payback & LCOP

Payback period is the time to recover the initial investment. Levelised cost of product (LCOP, or cash cost per kg) expresses the all-in cost to produce one unit of separated oxide or metal, the cleanest way to compare competing routes head to head.

How a TEA is built

A defensible TEA follows a repeatable sequence. Each step tightens the uncertainty band on the previous one.

1. 01

   Define the basis

   Set the feedstock grade and mineralogy, target product and purity, plant throughput, and location. These framing choices fix everything downstream.

2. 02

   Build the process model

   Lay out the flowsheet and resolve mass and energy balances, recoveries, reagent doses, water and energy per stage, anchored to bench or pilot data wherever possible.

3. 03

   Size and cost equipment

   Translate the balances into equipment lists, size each unit, and apply scaled or vendor-quoted costs to derive CAPEX with an explicit accuracy class.

4. 04

   Model operating cost

   Roll up reagent, energy, labour, maintenance and waste costs into annual and per-tonne OPEX, separating fixed from variable components.

5. 05

   Run the cash-flow model

   Combine CAPEX, OPEX, product revenue, taxes and financing into a discounted cash-flow model that yields NPV, IRR and payback.

6. 06

   Stress-test it

   Run sensitivity and scenario analysis on the variables the result is most exposed to, price, recovery, reagent cost, to find where the project breaks.

Why sensitivity analysis is the real output

A single NPV figure is the least interesting thing a TEA produces. The value is in the sensitivities, which assumptions the result is hostage to. In rare earth projects the recurring culprits are consistent: the prevailing price of the specific oxides in the basket (REE economics are basket economics, dominated by a few high-value elements), overall recovery across the chain, reagent consumption and price, energy cost, and the accuracy of the CAPEX estimate itself. A route whose returns survive a realistic downswing in any one of these is fundamentally more robust than one that only works at peak prices and best-case recoveries.

Where process improvement changes the economics

Because OPEX in REE processing is so heavily weighted toward reagents, energy and recovery losses, the economic leverage of a process is rarely in one dramatic breakthrough. It is in compounding efficiencies: a higher-grade, cleaner feed reduces reagent demand and losses in every stage that follows it; a more continuous, intensified operation can cut residence time, footprint and labour for the same output. TEA is the instrument that makes those gains legible, it translates “less reagent, less energy, better recovery” into a defensible movement in cash cost per kilogram and in NPV. That is precisely why we treat TEA as a first-class part of the research on this site, rather than an afterthought once the chemistry is settled.