Metallurgical accounting for rare earths

Rare earths turn the usual idea of grade into a list. A gold plant tracks one or two payable metals; rare earths accounting tracks rare earth oxide (REO) and neodymium and praseodymium (NdPr) together, and often the distribution of other individual elements as well. REO says how much rare earth material moved through the plant, and NdPr says how much of the material used in magnets went with it, so balances have to close for both, not just for one. MAX is built to handle that kind of multi-element accounting.

Many analytes, organised

A rare earths sample can carry a long list of results: individual oxides and elements as percentages or parts per million, liquor assays, densities, particle size and radioactivity. In MAX these can be held in data categories that group each kind of analyte, for example oxides in solids, oxides in liquor, elements in percent and parts per million, and activity, so hundreds of figures stay easy to find in worksheets, reports and dashboards. Laboratory files are imported with saved mappings, so a new set of results lands against the right sample points without retyping.

Formulas then calculate REO and NdPr grades, contained tonnes and recoveries for each stage, with rules for how each figure rolls up from shift to month, and the REO and NdPr calculations can be kept together in their own category. A “waterfall” report can show where REO and NdPr are lost between feed and product, stage by stage.

Concentration and hydrometallurgy

Concentration and hydrometallurgical processing can run in one plant or in separate plants. A concentrator might produce a mineral concentrate by crushing, grinding and flotation, and a hydrometallurgical plant then crack the concentrate with acid, leach it, remove impurities and precipitate an intermediate product such as a mixed rare earth carbonate. Where the two are separate, each has its own flowsheet, laboratory and reporting, and the concentrate leaving one is the feed for the other.

In MAX each plant can run as its own site, with its own plant model, formulas and reports, and the two can be linked: product dispatched by one is imported directly by the other, with its weights and assays already recorded, so the transfer is recorded once and agrees at both ends. See one site or several.

Product in bags and containers

Where concentrate or intermediate product leaves the plant in bags, bulk containers or truck loads, MAX tracks each one as a parcel with its wet and dry mass, moisture and oxide assays, groups them into batches, and records each transfer. Certificates of analysis are generated from the same figures, approved and numbered, so the certificate that goes with a container matches the data in MAX.

Reagents, water and residues

Acid cracking and leaching consume reagents, and water recovery and treatment may be reported alongside production. MAX can reconcile reagent consumption, such as sulphuric acid, and report water treatment readings and consumption, and tailings deposition can be reported in the same system. Residue streams carry REO and NdPr losses as well as mass, so they belong in the balance as measure points rather than being treated only as waste.

Reconciliation and reporting

Where tonnes and grades measured through the plant are reconciled each month to surveyed stockpiles and to product, MAX reconciliation distributes reconciled totals, such as dry tonnes, REO and NdPr, back across the month’s values, keeping each original value beside its reconciled one. Shift, daily, weekly and monthly reports, with draft and approved versions, are produced from the same data, so the figures the plant reports and the figures the business uses are the same figures.