Describe the solids loading
Record slurry flow, mass solids, particle-size distribution, mineralogy indicators, density, pH, conductivity, temperature and upstream collectors or depressants. Convert polymer use to active mass per dry solids.
Collect feed across the operating range. One low-solids sample cannot qualify a grade for peak plant flux.
Use feedwell dilution deliberately
Dilution can reduce local solids concentration and improve polymer distribution, but excessive water changes hydraulic loading and may weaken the desired bed. Document dilution ratio, water chemistry, injection location and mixing energy.
Check whether polymer contacts dilution water before slurry, enters with the feed, or is split between points. Each arrangement creates a different contact history.
Read four endpoints together
Measure initial settling or rise rate, overflow clarity, settled-bed volume or underflow density and floc response after shear. At plant scale add bed level, rake torque, underflow pump behavior and throughput.
Optimizing only settling speed can sacrifice clarity or compaction. Select a balanced operating window tied to the thickener bottleneck.
Confirm through residence
Hold feed and mechanical settings for each polymer condition, then wait long enough for overflow and bed response. Short steps can compare transient water rather than a stable thickener state.
Repeat the final condition during normal and difficult ore. Reconcile calculated dose with product inventory and retain matched feed, overflow and underflow samples.