THE EFFECTS OF POLYMERIC ADDITIVES ON THE CRYSTALLIZATION OF COMPOUNDS FOUND IN THE EVAPORATOR SCALES OF AUSTRALIAN SUGAR MILLS .1.

The composition of scales formed in multiple evaporator units at three Australian sugar mills have been determined using X-ray fluorescence (XRF), high performance liquid chromatography (HPLC), X-ray diffractio n (XRD), thermogravimetry/differential thermal analysis (TG/DTA) and o ther analytical methods. The composition of the scales formed in each mill have been found to be significantly different and to depend on wh ether they originated from early or later stages of the evaporation pr ocess. Calcium oxalate (present as the di and monohydrate) was identif ied as a major component of the scales from one mill but was found to be only a minor component of the scales from the other two. The latter were shown to contain two or more forms of calcium phosphate as domin ant phases. Amorphous or crystalline silica was found to be present in most of the scales examined.