The beginnings of pulp production from plantation pine

Early in the Second World War, APM participated in a joint program with government munitions authorities to develop a local source of wood pulp for nitrocellulose production. Eucalypt pulp was found to be unsuitable because of its high pentosan content and attention was then directed to radiata pine, which was becoming available, largely as thinnings, in South Australia. APM succeeded in adapting its kraft process to this new raw material and end-use and by 1943 its 'papered wood cellulose' had replaced imported pulp as the basis for cordite production. Later, APM developed a higher purity pulp -'alpha cellulose board' -for flashless cordite, made by adding a cold alkali refining stage after bleaching.

In 1942 a new paperboard mill started operation at Millicent, SA, owned by Cellulose Australia Ltd., a joint company between private interests and the South Australian Government. The mill, initially with one and later two relatively small paperboard machines, was designed to operate on wastepaper and imported pulp, supplemented by mechanical (groundwood) pulp produced on site from radiata pine thinnings, the suitability of which had been established in 1937 when successful commercial trials were carried out in Europe. Cellulose Australia became part of APM in 1969.

During the Second World War and later, APM gained considerable experience in the kraft pulping of radiata pine and carried out mill trials using this pulp in some of its products. Because of the young age of the wood available the pulp made was not as strong as imported softwood kraft but as it had some value when blended with eucalypt kraft APM continued to produce small quantities for its own use. An important bonus was a marked improvement in the operation of the black liquor evaporators and recovery furnaces, to the extent that the admixture of pine black liquor came eventually to be used to counteract the black liquor problems that arose when high proportions of old eucalypt mixed species were pulped.

Australian Academy of Technological Sciences and Engineering