Reagent Preparation & Make-Up Systems

How to use this guide

Make-up systems are often treated as “utility equipment” — until reagent performance drifts, lines scale, pumps cavitate, or operators fight gels and plugging. This guide is a practical decision aid to align procurement, EHS, and operations on system design, acceptance checks, and monitoring signals that keep dosing stable.

Use it to (1) choose the right preparation architecture (powder/emulsion/liquid), (2) size tanks and mixing realistically, (3) specify instrumentation that supports troubleshooting, and (4) write RFQs that produce comparable vendor offers — including documentation and spares.

Where it fits in a mining flowsheet

Reagent preparation is the bridge between chemicals procurement and metallurgical performance. Typical application points include:

• Flotation: collectors, frothers, modifiers, depressants (solution make-up + controlled dosing).
• Thickening & tailings: flocculants/coagulants (activation/inversion, aging, and low-shear delivery).
• Water recycle: pH control, clarifiers, scale control (stable concentration and feed-forward control).
• Leach/neutralization support: pH reagents and process aids (reliable solids handling and consistent solution strength).

The operating goal: stable concentration to the point of injection

A make-up system should produce a reagent stream with known, repeatable properties:

• Concentration: controlled and verifiable (by mass balance, density, conductivity, or titration checks).
• Condition: fully dissolved / properly inverted / correctly aged for performance (no gels, no lumps).
• Deliverability: pumpable and compatible with lines, valves, and injectors (no cavitation, no plugging).
• Safety: engineered controls for spills, dust, corrosivity, and slip hazards.

System architectures (what you are actually buying)

Key decision factors

• Ore mineralogy & process window: pH targets, hardness/alkalinity, and recycle water chemistry that affects reagent demand and stability.
• Separation KPI: recovery/grade, settling rate, overflow clarity, cake % solids, throughput stability.
• Reagent sensitivity: do you need aging (polymers), temperature control (some liquids), or low-shear transfer?
• Operations reality: staffing, maintenance capability, dust control, winterization, and power/water availability.
• Automation needs: manual batch make-up vs semi-automatic vs fully automatic concentration control.

Design checklist: the modules that make or break performance

1) Receiving & storage

• Packaging strategy: bags vs big-bags vs bulk; drums vs IBC vs bulk tanker.
• Storage conditions: temperature limits, humidity control (powders), freeze protection (emulsions), sunlight/UV sensitivity (some reagents).
• Containment: bunding/secondary containment sized for credible spill scenarios; compatible lining materials.
• Material compatibility: seals, gaskets, and plastics suited to pH and solvent exposure.

2) Wetting, dissolution, and “activation”

The goal is uniform wetting and controlled mixing. Too little mixing leaves lumps; too much can degrade sensitive reagents (especially high molecular weight polymers).

• Wetting device: wetting cone, eductor, or in-line disperser to avoid fisheyes and floating clumps.
• Mixing approach: high-energy only at the wetting point, then lower-shear mixing for conditioning.
• Water quality: hardness, iron, suspended solids, and temperature can change dissolution time and performance.
• Dust & slip control: powders need dust capture; polymers need spill plans (extreme slip hazard).

3) Aging / conditioning tanks (why they matter)

Some reagents need time after dissolution/inversion to reach stable performance. Aging also smooths process variability.

• Batch stability: aging tanks reduce “front-end” variability from feeder pulses or operator timing.
• Residence time: specify a realistic residence time target for your reagent family (supplier will advise by grade).
• Agitation level: enough to prevent stratification, but not so high that it damages structure or entrains air.

4) Day tanks, dilution, and delivery to dosing pumps

• Head & suction conditions: avoid long suction lines; keep NPSH margin; consider flooded suction for viscous reagents.
• Degassing/air management: air entrainment causes erratic pump output and flowmeter noise.
• Line design: minimize dead legs, provide flushing points, and design for cleaning and maintenance.
• Injection hardware: quills, check valves, and mixing tees sized for flow and solids carryover risk.

Sizing logic (practical, procurement-friendly)

You don’t need a perfect model; you need a design that prevents chronic instability. Start with these procurement-ready sizing questions:

Instrumentation that pays for itself

You don’t need “everything.” You need the minimum set that helps operators prove what changed when performance drifts.

• Flow measurement: for dilution water and reagent dosing (turndown and accuracy matter more than brand).
• Level: tank level transmitters with high/low alarms (prevent run-dry events and overflows).
• Density or conductivity: as a proxy for concentration on appropriate reagents (verify suitability with supplier).
• Pressure: injection and filter differential pressure to detect plugging/scaling early.
• Interlocks: prevent dosing when make-up is off-spec, or when critical utilities are lost.

Specification & acceptance checks (what to verify on receipt)

Separate chemical acceptance (COA/SDS) from equipment acceptance (FAT/SAT and documentation).

Chemicals (COA/SDS and logistics)

• Identity: product name, grade, manufacturer, batch/lot traceability, and intended use (e.g., thickener aid, flotation reagent).
• Quality: actives/assay, viscosity (liquids), moisture/bulk density (powders), pH (solutions), appearance.
• Handling notes: storage temperature range, shelf life, and any conditioning requirements.
• Packaging: liner type, closures, labeling, and compatibility with your pumps/hoses.
• Safety: current SDS, required PPE, spill response notes, and transport classifications (if applicable).
• Logistics: lead time, Incoterms, country of origin (if required), and spare packaging availability.

Equipment (FAT/SAT and documentation)

• P&IDs and GA drawings: with tag list and materials of construction.
• Motor/pump data sheets: including turndown, NPSH requirements, and seal materials.
• Instrument list: ranges, accuracy, and calibration procedures.
• Control philosophy: manual/semi-auto/auto; interlocks and alarms.
• Spare parts list: critical spares (seals, injectors, check valves, mixer components).
• Commissioning package: operator SOPs, maintenance schedule, and training.

Handling & storage (operations + EHS essentials)

• Dust control: powders require containment and housekeeping; specify local extraction where needed.
• Slip hazard: polymers and some surfactants can create extreme slip risk — plan spill containment and wash-down.
• Corrosives: ensure eyewash/shower availability, compatible PPE, and compatible containment materials.
• Segregation: store incompatibles separately; follow site chemical segregation rules and SDS guidance.
• Winterization: trace/insulate exposed lines and tanks where freezing is credible; plan for power loss scenarios.

Note: Some mining reagents require specialized regulatory compliance and site-specific procedures. Ensure your EHS program, training, and engineering controls match the hazard profile indicated in the supplier SDS and your site standards.

Troubleshooting signals (what to check first)

1) Poor settling / cloudy overflow

• Likely causes: concentration drift, incomplete dissolution/inversion, wrong injection point or mixing profile.
• First checks: verify make-up concentration (density/conductivity or lab check), confirm tanks are mixed and not stratified, inspect wetting device for plugging.

2) High reagent consumption

• Likely causes: dilution water variability, feeder calibration drift, air entrainment causing under-dosing, or process changes upstream.
• First checks: mass balance on chemical usage vs setpoint, calibrate feeder/pump, verify flow measurement and control valve behavior.

3) Scaling / plugging in lines

• Likely causes: dead legs, high local concentration, incompatible materials, or precipitation from mixing order.
• First checks: inspect and flush injection hardware, review line routing for dead ends, ensure designed dilution is happening before long runs.

4) Pump cavitation / noisy dosing

• Likely causes: long suction lines, gas entrainment, viscosity too high, tank level too low.
• First checks: ensure flooded suction where possible, remove suction restrictions, add de-aeration/venting if needed, confirm temperature is within spec.

5) Gels, fisheyes, or “stringy” solution

• Likely causes: poor wetting/inversion, wrong mixing energy at the wrong point, or make-up water quality issues.
• First checks: inspect wetting cone/eductor, confirm correct addition sequence, check for partially dissolved solids in tank corners and low-flow zones.

RFQ notes (what to include for accurate offers)

• Reagent family and form: powder/emulsion/liquid; any known sensitivities (temperature, shear, aging).
• Consumption profile: normal + peak usage, turndown requirements, and expected variability.
• Make-up targets: concentration operating window and whether dilution staging is required.
• Conditioning: required residence/aging time and acceptable agitation approach (low-shear vs high-shear).
• Utilities: water quality/pressure, power, heat tracing/steam availability, compressed air (if needed).
• Environment: dust exposure, winterization needs, enclosure requirements, area classification (if applicable).
• Automation level: manual batch, semi-auto with alarms, or fully automated concentration control.
• Documentation: P&IDs, GA drawings, instrument list, spares, FAT/SAT expectations, and training.
• Supply: monthly volumes, packaging preferences, destination, Incoterms, and documentation needs (CoA/SDS).

Educational content only. Always follow site EHS rules and the supplier SDS for safe use. System design and operating procedures must be validated for site-specific hazards, utilities, and regulatory requirements.