Nitric acid has been investigated in hydrometallurgical routes for recovering rare-earth elements from end-of-life neodymium-iron-boron magnets. Results depend on magnet grade, coating, oxidation, particle preparation, iron burden, acid balance and the downstream separation route. A successful laboratory paper does not make one process universal or justify immediate bulk purchase. This article focuses on nitric acid qualification, mass balance, materials and staged B2B supply. Process recipes, scale-up design, emissions treatment and environmental authorization belong to the recycler’s qualified engineering team.

For B2B qualification, assign purchasing, quality, engineering, operations, logistics and EHS ownership before the first commercial delivery. Approve the specification, analytical methods, sampling point, retained-sample period, storage conditions, transfer equipment, deviation response and release authority in writing. Compare representative lots under controlled conditions and record process performance, mass balance, waste, equipment observations and final quality. This separates raw-material variation from water, equipment, operator or analytical changes. Review the chain from supplier release through carrier, package, receiving connection and day tank because contamination or misidentification can occur after final analysis. Reconcile ordered, received, stored and consumed quantities and investigate unexplained differences. Supplier scorecards should cover documentation accuracy, delivery condition, corrective-action quality and change notification as well as price. Qualify an alternate source before a disruption using the same methods and process criteria. When buyer and supplier results differ, review sample representativeness, temperature, calibration, detection limits and uncertainty before deciding disposition. Confirm emergency contacts, unloading hours and stop-work authority for every shipment. Include maintenance and warehouse teams in post-trial review because they often identify seal, vent, hose or handling issues not visible in a certificate of analysis. Close qualification with an authorized report, approved supplier status and a defined routine-monitoring plan. Nitric acid is a strong oxidizer and corrosive chemical; the current SDS, local law and site procedures control segregation, handling, ventilation, exposure control and emergency response.

Characterize the magnet feed first

Document magnet source, grade, coatings, demagnetization, oxidation state, particle distribution and concentrations of neodymium, praseodymium, dysprosium, iron, boron, nickel, copper, cobalt and other contaminants. Mixed scrap may behave differently from clean production offcuts.

Use peer-reviewed evidence as a hypothesis

A 2023 RSC Advances study investigated oxidation, nitric-acid selective leaching and iron separation for NdFeB recycling. Its feed and conditions provide technical context, not a ready commercial design for every magnet stream.

Define recovery and selectivity together

Set targets for rare-earth extraction, iron co-dissolution, coating-metal behavior, reagent consumption, residue quality and downstream product purity. High extraction alone may create a larger purification and wastewater burden. Compare the whole flowsheet rather than a single leach result.

Close every experimental mass balance

Measure feed, liquor, washes, precipitates, residue and analytical samples. Reconcile rare earths, iron and key impurities with stated uncertainty. Apparent recovery that ignores sampling loss or moisture cannot support scale-up or reagent forecasting.

Specify nitric acid for reproducible development

Control assay, water, chloride, sulfate, metals and residue where they can affect kinetics, analysis or final purity. Record supplier lot and COA for every run. Use several representative lots so the process is not unknowingly tuned to one unusually clean sample.

Qualify the exact package and connection

Approve container, closure, venting, transfer connection and sampling method for the pilot facility. Packaging can add contamination or create handling risk. Scale package size only after consumption, storage and transfer controls have been demonstrated.

Design downstream and emissions controls early

Plan solid-liquid separation, washing, rare-earth purification, acid recovery or neutralization, nitrate management and residue disposition before optimizing leaching. Nitrogen oxide formation and oxidizing conditions require engineered closed reactors, ventilation, monitoring and abatement under the site hazard review.

Test materials with recycled liquors

Evaluate reactors, filters, pumps, seals, instruments and vents against fresh and recycle solutions. Accumulated metals and solids may change corrosion, filtration and heat behavior. Pilot campaigns should include upset and cleaning plans, not only steady operation.

Use stage gates for procurement

Begin with traceable laboratory packages, then estimate pilot demand from verified mass balances and campaign schedules. Require review before drum, IBC or larger delivery. Supplier scorecards should include analytical consistency, documentation, delivery condition and change notification.

Prepare a recycling-trial inquiry

Provide acid specification, trial quantity, package, destination, schedule and documentation needs without unnecessary proprietary process detail. Review the Hiacid nitric acid supply page, then request a staged pilot-supply proposal.

Related nitric acid resources

• Nitric Acid for Titanium Pickling Quality Control
• Nitric Acid Supply for Dairy CIP Systems
• Nitric Acid for Photovoltaic Silicon Wafer Texturing

Frequently asked questions

Is nitric acid the best leachant for every NdFeB feed?

No. Feed composition, preparation, selectivity and downstream recovery require comparative testing.

Why track iron co-dissolution?

Iron can dominate purification, residue and reagent economics even when rare-earth extraction is high.

When should a project move to pilot scale?

Only after repeatable balances, materials review, emissions control, downstream planning and hazard analysis.

Which acid attributes matter during development?

Assay, water, chloride, sulfate, metals, residue, packaging and lot traceability should be risk based.