Building material, perlite

Phosphoric acid or aluminium add phosphates can be used to bond asbestos sheets [42], glass wool [43], vermiculite [44], fly ash [45], mica [46] or perlite [47] to make building materials or electrically insulating compositions. Phosphoric acid and caldum aluminate can be combined to produce a strong cement for sparking plugs [48]. 

In addition to the related mineral interferences, other minerals common in building material may present a problem for some microscopists gypsum, anhydrite, bru-cite, quartz fibers, talc fibers or ribbons, wollastonite, perlite, attapulgite, etc. Other fibrous materials commonly present in workplaces are fiberglass, mineral wool, ceramic wool, refractory ceramic fibers, kevlar, nomex, synthetic fibers, graphite or carbon fibers, cellulose (paper or wood) fibers, metal fibers, etc. 

Filter aids as well as flocculants are employed to improve the filtration characteristics of hard-to-filter suspensions. A filter aid is a finely divided solid material, consisting of hard, strong particles that are, en masse, incompressible. The most common filter aids are applied as an admix to the suspension. These include diatomaceous earth, expanded perlite, Solkafloc, fly ash, or carbon. Filter aids build up a porous, permeable, and rigid lattice structure that retains solid particles and allows the liquid to pass through. These materials are applied in small quantities in clarification or in cases where compressible solids have the potential to foul the filter medium. 

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