Slurry Density and Percent Solids Calculator
Convert slurry density into useful solids estimates
What the calculator does
The tool estimates the volume fraction and mass fraction of solids in a two-phase slurry from three inputs: measured slurry density, solids density and carrier-liquid density. If volumetric flow is added, it also estimates dry-solids throughput.
It is useful for screening, checking units and structuring a conversation about process data. It is not an SDM ECO calibration tool and must not replace laboratory analysis, manufacturer instructions or competent process design.
Assumptions you must check
- The mixture contains one effective solids phase and one liquid phase
- Inputs use the same density units
- Volumes are treated as additive
- There is no material entrained-gas fraction
- Solids and liquid densities represent the process temperature and composition
- The measured density and flow represent the same stream and time period
Understand the three outputs
Solids by volume
The calculated fraction of the slurry volume occupied by solids. The tool uses the position of measured slurry density between the liquid and solids densities.
Solids by mass
The calculated proportion of total slurry mass contributed by the solids phase. This is not interchangeable with percentage solids by volume.
Dry-solids throughput
When volumetric flow is supplied, the tool multiplies flow by the calculated solids volume fraction and solids density. The result is only as reliable as the aligned inputs.
Use consistent units and representative values
Density may be expressed as kg/m³, g/l or t/m³, but all three density inputs must use a consistent basis. The calculator labels kg/m³ to reduce ambiguity. If another consistent unit is used, the percentages remain dimensionless, but the displayed throughput unit would no longer be valid.
Carrier-liquid density changes with temperature and dissolved material. The SDM ECO manual includes a reference table for water density across temperature, but real process liquor may differ.
Why a calculated percentage can be wrong
Entrained air lowers bulk density without representing less solid in the simple two-phase model. Mixed minerals need an appropriate effective solids density. Dissolved solids change liquid density. Samples can segregate or fail to represent the online stream.
Use sensitivity checks instead of presenting excessive decimal precision. Validate the selected inputs, sampling method and process interpretation before using a result for control, reporting or commercial decisions.
Interactive slurry calculation
Calculate solids concentration from measured density
Enter all densities in the same units. kg/m³ is shown below. This tool assumes a two-phase mixture with no entrained gas.
Calculated result
Solids by volume:
Solids by mass:
Estimated dry-solids throughput:
Important: This is a first-pass mass-balance calculation, not a calibration, process guarantee or safety-critical design tool. Mixed minerals, dissolved solids, temperature, entrained air and sampling error can change the result. Validate inputs and outputs with competent process engineering and representative site data.
Formula basis
Solids volume fraction: Cv = (ρslurry − ρliquid) ÷ (ρsolids − ρliquid).
Solids mass fraction: Cw = Cv × ρsolids ÷ ρslurry.
Estimated dry-solids throughput: Q × Cv × ρsolids, with unit conversion to tonnes per hour when Q is m³/h and density is kg/m³.
Use the result alongside the mining measurement guide or dredging density and flow guide.
Frequently asked questions
Is percent solids by mass the same as percent solids by volume?
No. They use different denominators and will differ whenever the solids and liquid densities differ.
Can I calculate dry-solids throughput from density alone?
No. You also need volumetric flow plus appropriate solids and liquid densities. The measurements must represent the same stream and time basis.
What happens if the slurry contains air?
The two-phase calculation can understate solids because gas lowers measured bulk density. Treat aerated or three-phase mixtures separately and seek application-specific review.
Sources and review scope
Calculation basis reviewed 10 September 2026 as a two-phase mass and volume balance. Water-density context is cross-checked against Appendix B of the SDM ECO operating manual. This educational tool does not reproduce a manufacturer calibration and does not warrant a process result.
Turn the calculation into an application review
Send PMA the raw densities, units, temperature, composition, flow source, sampling method and intended decision. We can help identify what must be verified before selecting or commissioning an online measurement.