Sappleton, D., Thompson, C., and Barr, M.

Alumina Partners of Jamaica (Alpart), the largest alumina refinery in Jamaica, was commissioned in 1969 with three batch precipitation trains and only one continuous train. In the early 1970’s another batch train was added, and in the early 1980’s two of the batch trains were converted to continuous trains. However, based on available data, it proved best to use the remaining batch trains as the primary agglomeration trains.

In order to enhance its global competitiveness, Alpart embarked on a modernization program aimed at making improvements to product quality and cost. Alpart has since reviewed its philosophy on the use of batch technology, which adversely affects product soda, attrition index, yield, classification operation and operating cost. Subsequently, in addition to changes in the classification and seed charge systems, the remaining batch trains were converted to continuous trains.

The estimated impact of the conversion of the batch precipitators, using Kaiser technology, is a 1.5 gpL overall yield improvement, a 5% reduction in the average Attrition Index and a 18% reduction in Product Soda.

This paper describes the operational, maintenance, and construction aspects of the process of converting from batch to continuous precipitation without any impact on plant performance.