Thickening
Feed, inventory, clarification and discharge as parts of one process.
Explore the topicKnowledge
Thickeners, signals and operating decisions
Explore process mechanisms, the variables worth comparing and the limits of each explanation.
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Sedimentation
Test conditions, flocculation and the limits of scale-up to the plant.
Explore the topicTailings and water recovery
Water balance, net recovery and constraints downstream of the thickener.
Explore the topicInstrumentation and data
Signals, historical records and the conditions needed to reconstruct an operating event.
Explore the topicModelling and control
Process representation, temporal validation and decisions before automation.
Explore the topicThickening 3 min
Why feed is an underestimated thickener disturbance
Feed is one of the main disturbances affecting a thickener. It does not change only in flow rate or solids concentration. Particle-size distribution, material composition, water chemistry and settling response can…
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Tailings and water recovery 2 min
When higher water discharge from a thickener represents net recovery
Not necessarily. The balance boundary must be defined and the change must be shown to reduce the make-up water required by the circuit. Water may be recovered earlier in the thickener and no longer recovered later at…
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Thickening 3 min
How a tailings thickener works
A thickener receives slurry, promotes separation between solids and water, removes clarified water through the overflow and discharges a more concentrated slurry through the underflow. Its response depends on how…
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Sedimentation 4 min
How to measure tailings settling velocity
Record the height of a defined interface or level, `h(t)`, during a test with documented conditions. Over an interval where the curve is approximately linear, the downward velocity can be estimated as `v_s = (h_1 -…
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Sedimentation 3 min
How much flocculant should a thickener use?
There is no universal dosage that can be defined without considering the incoming material and the response required. The necessary dosage depends, among other conditions, on particle-size distribution, the amount of…
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Modelling and control 3 min
Why having data does not mean having control
Data describe measurements. Control requires interpreting the process state, distinguishing disturbances, choosing an action and observing its effect. A dataset may contain many rows and still fail to reconstruct…
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Sedimentation 4 min
How to detect changes in settleability before they affect a thickener
A repeated, comparable upstream measurement of settling response is required, together with a baseline separated by material regime and a temporal association with the subsequent thickener response. The early signal…
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Instrumentation and data 2 min
The process historian is not the plant
A historian stores values and timestamps. It does not necessarily store the operating regime, instrument condition, disturbances, manual actions or constraints that explain those values.
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Instrumentation and data 3 min
The sensor seemed to be working
A signal can respond to process variations and maintain a reasonable appearance while the instrument's physical condition changes slowly. Build-up, drift, loss of calibration or an installation condition can shift…
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Sedimentation 3 min
Why a cylinder test does not necessarily reproduce in the plant
Scaling a result is not just a matter of increasing volume. The laboratory test and the plant may use the same tailings and flocculant while operating with different mixing, shear, dilution, residence time, solids…
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Thickening 3 min
What causes torque to rise in a thickener?
Torque rises when the rakes encounter more resistance while moving material. Bed level can contribute, but it is not the only cause. Solids concentration and compaction, rheological behaviour, feed settleability,…
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Sedimentation 4 min
What an automated settling test measures—and does not prove
An automated system can record the evolution of an interface or associated signal during a test and derive a curve, characteristic times and slopes under documented conditions. It can also improve the traceability of…
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Instrumentation and data 4 min
What technologies can monitor settling in real time?
No single technology measures the entire phenomenon. A manual or automated test characterises a sample under defined conditions. Online instruments observe process variables such as bed, inventory, density, flow or…
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Instrumentation and data 2 min
One signal does not explain an operating decision
A signal shows one part of the process response. Explaining a decision requires reconstructing what changed, how the system responded, which action was taken and which effect appeared afterwards.
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Modelling and control 2 min
How to validate a model before using it for a control decision
It remains to be evaluated whether the model retains usefulness on data that did not participate in fitting and whether it represents the intended decision. A good retrospective fit may depend on future information,…
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