Enter the extraction ratio, concentration in output stream, and concentration in input stream into the calculator to determine the missing variable.

Extraction Ratio Calculator

Enter any 2 values to calculate the missing variable (ppm is treated as mg/L for dilute aqueous solutions).

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Extraction Ratio Formula

The following formula is used to calculate the extraction ratio (fraction removed) for a given concentration in the input and output streams.

ER = (C_i - C_o) / C_i

Variables:

  • ER is the extraction ratio
  • Co is the concentration in the output stream
  • Ci is the concentration in the input stream

To calculate the extraction ratio, subtract the concentration in the output stream from the concentration in the input stream, then divide the result by the concentration in the input stream.

What is an Extraction Ratio?

The extraction ratio (sometimes called the extraction fraction) is a unitless measure of how much of a substance is removed from a stream between an inlet (“input stream”) and an outlet (“output stream”). When defined as ER = (Ci − Co) / Ci, it represents the fractional decrease in concentration from input to output (assuming the concentrations are measured on the same basis). Values closer to 1 indicate more removal, while values near 0 indicate little removal. If the output concentration is higher than the input concentration, the computed ER will be negative, indicating a net increase rather than extraction.

How to Calculate Extraction Ratio?

The following steps outline how to calculate the Extraction Ratio.

  1. First, determine the concentration in the input stream (Ci).
  2. Next, determine the concentration in the output stream (Co).
  3. Next, calculate the extraction ratio using the formula ER = (Ci – Co) / Ci.
  4. Finally, interpret the result as a unitless fraction (often reported as a percentage by multiplying by 100).
  5. After inserting the values and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Concentration in the input stream (Ci) = 5 mg/L

Concentration in the output stream (Co) = 2 mg/L

Extraction Ratio (ER) = (5 − 2) / 5 = 0.6 (60%)