ASTM D4085-93(2013)

4.1 Manganese in pulp acts as a catalyst in oxidizing cellulose.

4.2 Iron in pulp can cause yellowness in rayon fibers and influence cellulose acetate plastics color. Iron also causes problems in photographic and blueprint papers.

4.3 Copper in pulp can act as a retardant in oxidizing cellulose and can affect viscose ripening. Copper interferes with the dye level of rayon fibers and influences cellulose acetate plastics color.

4.4 Calcium in pulps can cause problems in processing into acetate, rayon, cellophane, etc. Calcium can create undesirable deposits in viscose spinning and film casting operation. Calcium can influence viscosity control during cellulose acetate manufacture.