Mass Recovery
Calculate the mass recovery (mass yield) of a mineral processing operation, R = (concentrate mass ÷ feed mass) × 100%, dividing the concentrate mass produced by the ore feed mass. The result, in %, is the fraction of mass reporting to the concentrate — different from metallurgical recovery (which measures the fraction of metal recovered). Low mass recovery is typical of lean ores (little concentrate from much feed); high indicates rich ore or poorly selective concentration. Combined with the grades, it closes the plant's mass balance. Enter the concentrate and feed masses.
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Mass recovery
In mineral processing (the stage that separates the valuable minerals from the barren gangue, by flotation, magnetic separation, gravity separation and so on), two different indicators measure performance, and mixing them up is a common mistake. Mass recovery (or mass yield) is R = (concentrate mass ÷ feed mass) × 100% — the fraction of the total mass that reported to the concentrate. Metallurgical recovery, by contrast, measures the fraction of the metal (or valuable mineral) that was recovered, taking the grades into account. They are distinct quantities: a lean ore (low grade) that concentrates well may show low mass recovery (little concentrate from a lot of feed, since there is little valuable mineral to concentrate) and yet high metallurgical recovery (almost all the metal went to the concentrate). Take a 1% copper ore that yields a 25% concentrate: mass recovery is low (~4%, since 96% of the mass is rejected waste), while metallurgical recovery may reach 90% or more, because most of the copper was recovered. Mass recovery matters for sizing the material flows of the plant: how much concentrate to produce, how much tailings to generate (bound for dams or stockpiles), and the overall mass balance. Together with the feed, concentrate and tailings grades, it closes the metallurgical balance through the two-product equations, which makes it possible to compute everything from partial measurements. Mass recovery, metallurgical recovery and the grades together form the set of indicators used to assess and control a concentration plant. Enter the concentrate and feed masses.
Related Tools
Concentration Ratio
Compute the concentration ratio of a processing operation, CR = feed mass / concentrate mass, how many tonnes of raw ore are needed to produce one tonne of concentrate. It measures the degree of upgrade: high ratios indicate lean ores that require heavy processing. It is useful in the mass balance and plant sizing. Enter the feed mass and the concentrate mass.
Slurry Mass Concentration
Calculate the solids mass (weight) concentration in a slurry, C_w = C_v·(ρ_s ÷ ρ_m)·100, from the volumetric concentration C_v (fraction), the solids density ρ_s and the mixture density ρ_m (kg/m³); the result is a percentage. Mass concentration is the fraction of the total slurry MASS that is solid (kg of solid per kg of slurry), different from volumetric concentration (volume fraction). Both measure the same thing differently, and their relation depends on the solids density: since solids are DENSER than water (sand ~2.65×), mass concentration is always GREATER than volumetric (a slurry with 20% solids by volume has about 40% by mass). Mass concentration (% solids by weight) is the form most used in the mineral industry and ore processing, since it relates directly to the tonnage of solids processed and is what is controlled in thickeners, mills and flotation. Converting between mass and volumetric concentration is a daily operation in processing-plant mass balance and pipeline and dredging control. Enter the volumetric concentration, the solids density and the mixture density.
Metallurgical Recovery
Compute the metallurgical recovery of a processing plant, R = (metal in concentrate / metal in feed)·100%, the fraction of the metal contained in the ore that is actually recovered into the concentrate. It is the key measure of plant efficiency: the unrecovered metal is lost in the tailings. Small recovery gains represent large value in large-scale operations. Enter the mass of metal in the concentrate and in the feed.
Pulp Dilution Water
Computes how much water must be added to take a pulp from one mass percent solids to a lower one, Water = M × (C₁/C₂ − 1), where M is the incoming pulp mass (or mass flow). It follows from the mass balance: the solids mass does not change on dilution, so the final pulp mass is M·C₁/C₂ and the difference is water. This is the most routine operation in a mineral processing plant — grinding, desliming, flotation and thickening each demand their own percent-solids range, and getting the dilution water wrong throws off residence time, viscosity and reagent consumption. Both percentages are by mass (weight of solids per weight of pulp), and the result comes out in the same unit entered for M. Enter the pulp mass or flow, the current percent solids and the target percent solids.
Mining Recovery
Compute the mining recovery, R = (mined ore / in-situ ore)·100%, the fraction of the ore originally present in the deposit that is actually extracted. Not all ore is recoverable: support pillars, blasting losses and contacts leave part behind. Together with dilution, it defines the extraction efficiency and the mineable reserves. Enter the mined ore and the in-situ ore.
Cheese Yield (Van Slyke Formula)
Estimates how many kilograms of cheese come out of 100 kg of milk using the Van Slyke formula: 93% of the milk fat is added to the casein content, 0.1 point is discounted as loss to the whey, the sum is multiplied by 1.09 to include the salt and ash retained in the curd, and all of it is divided by (1 minus the cheese moisture). The result is the theoretical yield, the reference against which the real plant loss is measured: a gap above half a point between the theoretical figure and the vat balance is almost always fat escaping into the whey or curd cut at the wrong moment. Note that moisture sits in the denominator and dominates the result — the same milk yields 11.2 kg in a soft cheese at 45% moisture and only 9.5 kg in a hard cheese at 35%, and that difference is water, not solids, so a high yield on its own does not mean a better process. The classic Van Slyke form was adopted, with the 0.93 fat retention coefficient and the 1.09 factor; dairies usually recalibrate both numbers for their own process, and for milk standardised by ultrafiltration the formula underestimates the yield. Enter the milk fat, the milk casein and the target cheese moisture.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.