An interesting aspect of milling is the evaluation of the performance of each mill in the tandem. Early (1921-1931) analytical techniques are described in Browne & Zerban (1948); sampling is discussed in the SASTA Laboratory Manual (1985). Material balances across milling tandems normally use 4 main assumptions which are not all rigorously correct:
Literature on the chemical cleaning of evaporators was available in 1929 (Spencer & Meade; 1948); in most cases sodium hydroxide and soda ash were boiled individually or as mixtures in the vessels which were then drained and washed. A boiling with hydrochloric acid would follow if necessary. Spraying techniques in Java and Hawaii were seen to be more economical in terms of chemical quantities. Fermented molasses was used in Queensland in the early 1930’s, and Honig (1953) quotes results obtained in 1949 from Taiwan.