THIS paper presents the concept of an Integrated Agro-Industrial Complex
(IAIC) producing five or six products from two or three crops. The complex
would operate on a year round basis with the ‘wastes’ of one product being the
feedstock for another. The complex could be introduced in stages to an existing
sugar mill and is illustrated in block flow diagram and described in the text. The
concept is based on existing and developing practice in producing sugar, paper
pulp and fertiliser. By integrating operations we believe the sugar industry could
effect a major increase in income, profitability and market flexibility. By
expanding into new growth areas the concept could minimise Australia’s energy
and climate change problems. Potential products of an IAIC include; paper pulp,
motor fuel ethanol, Ecophos a non-leaching fertiliser, sugar, lignin and electric
power. Crops include; high fibre sugarcanes, sweet sorghum and nalgrass. Other
raw materials include; phosphatic mine waste, fertiliser grade potash, lime and
hydrogen peroxide. The main ‘wastes’ arise from producing paper pulp and are
pith and other fines removed from bagasse to make a strong paper pulp, and
potash pulping black liquor. Integration of sugar milling with the processing of
other products allows a major saving in capital and operating costs. In particular
it avoids the storage and reclaim of bagasse ahead of paper pulp production.
Integration also allows the production of ethanol without the need to produce
and dilute molasses feedstock. As an indication, the requirement of modifying an
‘average size’ sugar mill could be of the order of $100 million and the
engagement of 30 extra mill employees. The exact numbers would depend on
location and product mix. The major capital and operating costs involve addition
of an ethanol plant. Potash pulping without reagent recycling is relatively cheap,
as is alkali fertiliser manufacture from crandallites (the overburden waste from
certain phosphate mines).