Grinding-circuit hydrocyclone classifier — a COOLPROP process flowsheet
A hydrocyclone classifies a mineral slurry by particle size — the unit that closes every closed-circuit grinding loop (mill → cyclone, coarse underflow recycled to the mill). A quartz slurry (200 µm mean, spread by a log-normal PSD) is split about a 100 µm corrected cut size (Plitt 1976): the coarse solids report to the thick underflow and the fines to the dilute overflow, split by the short-circuit recovery. The underflow comes out much coarser (~300 µm mean) than the overflow (~80 µm), and the solids mass balance closes exactly. Honest scope: the d50c is the real Plitt correlation, but the partition sharpness and water recovery are screening params.
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- Rigorous COOLPROP thermodynamics, solved by the same engine every simulation runs on.
- 1 unit operations modeled: HC.
- Focus areas: Minerals, Comminution, Hydrocyclone, Classification, Plitt.
- Thermodynamics
- COOLPROP
- Components
- quartz, water
- Unit operations
- HC
Opens in a new tab, loaded straight into the app — no setup.
Read the step-by-step guideReproduce this exact result from Python — the real client.get_example() → run_and_wait() path, not a mockup.
from flowsim.sdk import FlowSimClient
client = FlowSimClient()
example = client.get_example("grinding-circuit-hydrocyclone")
sim = client.create_simulation(example["title"], example["flowsheet"])
result = client.run_and_wait(sim["id"])
print(result["status"]) # "converged"
streams = client.streams(sim["id"])Related models
Grinding circuit: what a size reduction costs
Ore at 1 mm is ground to a 100 micron P₈₀ and screened at 150 microns. The number the example exists for is the 172.3 kW the mill draws, and it is not a parameter — it is Bond's Law computed from the size reduction itself: W = 10 x Wi x (1/sqrt(P₈₀) - 1/sqrt(F₈₀)) with sizes in microns gives 9.57 kWh/t at a Bond work index of 14, and 18 t/h of ore turns that into 172.3 kW. Halve the product size again and the law's inverse-square-root shape is what tells you the power does not halve — comminution is where a mineral plant's electricity goes, and this is the relationship that decides it. The screen then splits the ground product 27.9% oversize / 72.1% undersize, and it genuinely sorts: the oversize leaves at a 247 micron mean against the undersize's 81 microns, from one 100 micron feed. The cut is applied to the real size distribution (GSD 2.0), not as a specified split fraction. Open circuit, for the Bond's-law arithmetic. A real grinding circuit recycles the screen oversize back to the mill; that closed circuit, with the particle-size distribution carried class by class through a crusher, screens and a breakage-function mill, is the closed-circuit-crushing-and-grinding example.
Closed-circuit crushing and grinding, with the size distribution carried
180 t/h of quartz ore at a 60 mm median goes through a cone crusher in closed circuit with a 16 mm screen, then a ball mill in closed circuit with a 150 micron screen. Every solid stream carries its full particle-size distribution, class by class, so each unit acts on the distribution rather than on a median and a spread. The crusher is Whiten's model: everything finer than its 12 mm closed-side setting passes, everything coarser than its 30 mm open-side setting is broken, and between them a classification function decides. It reduces the circuit feed from an F₈₀ of 90 mm to 13.4 mm for 165 kW, and the screen returns 19% of what it receives to it. The mill is a breakage/selection-function size-mass balance in three mixed stages, not a target size: its product is whatever the breakage of each class produces, fines tail included. The 150 micron screen sends 72% of the mill discharge back, a circulating load of 258% that nobody specified — it is where the recycle settles given the breakage rate and the screen's sharpness. The circuit product leaves at a P₈₀ of 158 microns, and the screen recovers 81% of the true undersize, because a screen with a sharpness of 3 is not a perfect cut. Bounded, and stated. The mill's power is Bond's law applied to the mill's own throughput and its own F₈₀ and P₈₀; Bond's work index is defined on the circuit's fresh feed, so read it as a screening number. The breakage function is Broadbent-Callcott and the selection exponent 1.0 — an ore's own breakage and selection parameters come from its laboratory tests and replace them. Dry circuit: water is not carried.
Grinding to liberate, flotation to recover: a copper rougher
97 t/h of a 2 wt% chalcopyrite ore in quartz, crushed to a 2 mm median, is ground in a grate-discharge mill and floated in an 8-cell rougher bank. The feed declares its composition by size (psd_minerals) and its texture (150 micron grains), so every unit acts on mineral by size, not on one distribution. The mill is Whiten's perfectly mixed mill with a 0.6 mm grate: nothing coarser can leave, so the coarse fraction is held and ground until it passes. That is why the mean residence time comes out at 643 s against the 300 s the fines see, and the mill holds 17.9 t. The product P₈₀ is 240 microns for 615 kW. Chalcopyrite breaks 1.5 times faster than quartz here, so it ends up enriched in the fines. Liberation is computed, not assumed: at 150 micron grains only 17% of the chalcopyrite sits in fully liberated particles at this grind. The rougher floats every particle type at a rate set by its grade, so a composite floats slower than a liberated grain and drags quartz with it. It recovers 87.0% of the chalcopyrite into 15.4% of the mass, a concentrate grade of 11.3% against 2% in the feed, and leaves 0.31% in the tailings. The sensitivity is the grind-recovery trade. Grind longer and recovery and grade rise together (80% at 100 s, 93% at 900 s) while the mill's power rises with them, which is the decision a concentrator's grind size is set on. Bounded, and stated. Every ore parameter here is illustrative and fitted to no deposit: the selection rate, the grain size and the flotation rate constants are measured per ore (the breakage-fit tool measures the first from a batch test). A composite's flotation rate is taken as proportional to its grade (linear exposure); there is no froth recovery, no size dependence of the rate beyond liberation, and one valuable mineral.
Solids train (crystallize → filter → dry)
An MSMPR crystallizer feeds a cake filter and dryer — the crystal size and cake moisture propagate on the stream's solids payload (pharma / minerals workflow).
Crystallization with agglomeration (distributed CSD)
An MSMPR crystallizer solved with the rigorous distributed population balance (not just moments): the full crystal-size distribution is computed on a size grid, and an agglomeration (aggregation) kernel combines fine crystals into larger ones — coarsening the mass-weighted mean size (d43) and broadening the distribution (CV rises above the growth-only MSMPR value of ~1.0) while conserving mass exactly. The distribution, its coefficient of variation, and d43 propagate on the solid stream into the filter and dryer — the gPROMS/gCRYSTAL capability the moment model structurally cannot provide.
Crystallization + granulation finishing
A continuous MSMPR crystallizer, cake filter, and dryer feed a granulator that grows the dried crystals into free-flowing granules — the finished-product train after the mother liquor and dryer vapor leave.