Washing of Raw Salt-Washing Efficiency

Washing of Raw Salt -Washing Efficiency

Washing efficiency is used to calculate the degree of impurity removal from raw salt after washing. The formula is defined as follows:

η=(q₁-q₂)/q_1​​×100%

η: Washing efficiency of raw salt.

q_1​: Dry basis content of a certain impurity in raw salt before washing

q₂​: Dry basis content of a certain impurity in raw salt after washing

The impurity content can also be expressed in terms of salt or ions.

Example

The composition of raw salt and washed salt from a salt factory is shown in the table below. Calculate the washing efficiency of the raw salt.

Solution

First, convert the composition of raw salt to dry basis content (as shown in the table above). Then, calculate the washing efficiency for each impurity category:

Washing Efficiency of MgCl₂: η=(0.84-0.19)/0.84*100%=77.4%

Washing Efficiency of MgSO₄: η=(0.38-0.08)/0.38*100%=78.9%

Washing Efficiency of CaSO₄: η=(0.56-0.36)/0.56*100%=35.7%

Washing Efficiency of Insolubles: η=(0.38-0.16)/0.38*100%=57.9%

Summary

The washing efficiencies for the impurities in raw salt are as follows:

MgCl₂: 77.4%

MgSO₄: 78.9%

CaSO₄: 35.7%

Insolubles: 57.9%

This calculation demonstrates the effectiveness of the washing process in removing different types of impurities from raw salt.