... 3.whiteness:93min 4.Used for plastic,rubber,chemical,papermaking etc. Limestone Powder and lump for PVC Application: 200mesh: as ... -400mesh:gusset plate,chemical,pipe 400-600mesh:toothpaste and soap 800mesh:rubber,pvc,plastic,electric cable 1250mesh ... reaction,reselection.dehydration,drying and depolymerization.It is adopted the technics of particular multi-selection and secondary depolymerization.2. ...