Ash measurement and control: what is accurate enough?

The use of fillers and pigments improves optical and printing properties while bringing process benefits and providing savings in raw material costs. For example, the presence of fillers improves dewatering in the wire and press sections thereby reducing energy consumption. However, if papermakers are to reap the full benefits from fillers and pigments -by understanding the problems they can generate -continuous measurement and control is essential. But this presents a challenge, because of the great diversity in shape, density, surface properties, charge etc - factors which make ○ reliable and accurate measurement difficult, and ○ the control of wet end stability more demanding. Properties such as solubility, abrasivity, density, particle shape, etc determine how troublesome or good fillers and pigments (as coated broke) are in a furnish.