We would like to use phospho-gypsum in place of mineral gypsum in our cement plant. Please advice us of its suitability. Phospho-gypsum has 36 per cent moisture and pH is 2.3. The cost of using this material is very low but what are the drawbacks?

I know of no reason why you should not use phosphogypsum. However, you will have to conduct trials to verify that no product quality problems are involved.

My Company is planning to install a New Cement Grinding Plant with a capacity of 150tph, The Supplier is insisting to have separate mill ventilation bag filter, and the separator fines to be collected through another bag filter. My idea is to have only one bag filter in common while mill ventilation duct is connected to a static grit separator before this bag filter, and the separator fines are collected through a cyclone collection. I understand the advantages and disadvantages of both systems but what I'm not able to understand is why they are insisting on this.

I also don't know the reason why the supplier is insisting on two bag filters. There are many cement mills operating with a single filter and a circuit layout similar to the one you envisage. If you refer the supplier to me I might be able to understand their reasoning. At this stage I cannot.