Pls give some details of theory and principles of Dry mixing of powders?

Answer 1

See
http://www.ajax.co.uk/conmix.htm
http://course1.winona.edu/bperatt/personal/Professional/Abstract.htm
http://www.cavicchiimpianti.com/PRM/en/mixing-powder-processing-systems.html

I am a chemical engineer though not an expert in this area. I believe there is a wide range of equipment used to accomplish this task dependent on such factors as desired throughput, particle size and size distribution and powder properties. The manufacturers of such equipment will have developed empirical relationships based on a number of parameters that will enable them to determine the performance of their equipment perhaps the most important being residence time.