Phosphate ore to marketable rock: attrition scrubbing, desliming, flotation

The front of the phosphate chain, ahead of the acid plant: 100 kg/s (360 t/h) of a sedimentary phosphate ore at 21.9% P2O5 (47.9% BPL) is scrubbed, deslimed at 105 microns and floated to a concentrate. The ore is fluorapatite with quartz, dolomite and kaolinite clay; it declares its size distribution and its composition by size, with the clay concentrated in the fines and bound into agglomerates in the coarse classes. Mineral densities are the published ones (fluorapatite 3.15 within the 3.1-3.2 range, quartz 2.65, dolomite 2.84, kaolinite 2.6 g/cm3). The attrition scrubber releases 80% of the coarse-bound clay below the cut and deslimes at 105 microns (150 mesh, the size Florida plants deslime at, Zhang et al., OSTI 1439932). 17.3% of the solids go to the slimes at 11.2% P2O5, so 8.9% of the P2O5 is lost with them; the deslimed sand is 24.1% P2O5. How much P2O5 a plant loses here is set by how much apatite is in the fines: Florida's matrix loses about a third of its P2O5 to the clays (the same report), this ore much less. The rougher floats fluorapatite at a rate set by each particle's grade: with 1 mm grains, 46% of the apatite in the deslimed feed sits in liberated particles. It recovers 95.3% of the deslimed apatite into a concentrate of 30.5% P2O5 (66.7% BPL), inside the 28.7-31.3% P2O5 of marketable phosphate rock (Smol et al., Materials 2023), at an overall recovery of 86.9% of the ore's P2O5. Bounded, and stated. Every ore parameter is illustrative and fitted to no deposit: the size distribution, the grade by size, the clay disaggregation, the grain size and the flotation rate constants are measured per ore and reagent scheme, and 1 kWh/t of scrubbing energy is a placeholder for the power figure. One rate constant serves all gangue, so dolomite floats no better than quartz here, which is the opposite of the real difficulty with carbonate phosphates (a reverse carbonate flotation or a dense-medium step is the usual answer). No froth, no entrainment beyond water recovery, no reagent consumption.