The time required for carrying out the mass contacting step in Problem 4.1 needs to be determined. Develop the model equations that will enable this to be done. How would you simplify this model and...

The time required for carrying out the mass contacting step in Problem 4.1 needs to be determined. Develop the model equations that will enable this to be done. How would you simplify this model and what assumptions did you make? What quantities must you know to determine the time to carry out the extraction specified in Example 4.1?