how blenders are being validated & what is selection criteria for which type of blender to be used & on what basis we decide hoe much powder can be blended at a time
Blenders are validated for following parameters:
Mixing load
Blender RPM (rotation per minute)
Content uniformity
Evaluation of worst case: Worst case include, maximum and minimum load, maximum and minimum rpm, number of materials to be blend (maximum and minimum), % content of material to be mixed in the mixture (maximum and minimum).
For selecting the criteria for which type of blender, it is dependent on the nature of the material that you are mixing, your proccess requirement etc.
For deciding how much powder can be blended at a time refer the supplier specification and your validation results. If no datas are available then determine by mixing different load and analyzing the results of mixing. On the basis of the analytical result you can determine the load.