i want to mathematically model the pneumatic mixing of dry cement and other powdery substances in silos and determine the optimum pressure of mixing according to the composition of the mix and also calculate the degree of homogeneity

its urgent

thank you

mudit■

When mixing two bulk materials with different densities there is a potential drawback of segregation. Even if mixed very aggressively, as by a Forburg mixer, there is a large potential for separation to take place at the unloading or at a subsequent handling stages. A simple test is to hand mix a small sample and then pour the mix onto a flat plat through a funnel. compare samples from the periphery of the pile with one from the central regions should show if segregation could be a problem. Drum mixers are prone to sifting segregation of dry products due to the repetitive dynamic repose slope that is generated. You may be interested in the book. - "User Guide to Segregation', published by The British Materials Handling Board for more background on the subject. At £ 30 plus £ 5 postage, it could offer good insurance against a costly mistake.

Depending on the quantity involved and the flow characteristics of the fraction, continuous mixing usually offers a good protection against segregation and in some cases, gravity static mixing can be an ideal solution. If you care to send small samples of the ingredients to Lyn, at Ajax Equipment Ltd. Mule Street, Bolton. BL2 2AR, with an outline of the duty, I will be pleased to advise and put forward recommendations. ■

The chemical mixture and composition of different materials are reffered to as composite density

or solution density. As it is the mass of a substance per unit volume such as pounds per gallon. ■