Saiccor - The First 50 Years 5.8 MB - Sappi

The First Fifty Years
As discussions with suppliers about plant and equipment for the
magnesium plant had been ongoing since 1981, the final requirements
were soon established and orders placed� The recovery boiler and
secondary recovery were ordered from Gotaverken (who
subcontracted the construction to ICAL and ND Engineering), the
washing plant from Rauma Repola, and the evaporator from APV
Kestner – both constructed by ND Engineering� The digesters, tanks
and pipework were ordered from ND Engineering, the turbo-generator
from SGP (Austria), the process control system from Control
Specialists (Fischer Provox), and instrumentation and electrics from
UIC� The civil design was to be carried out by CBI and civil
construction by Murray and Roberts�
Shortly after the main orders had been placed, a telex from Chris
Hogg arrived: ‘My friend Lord Wienstock is most disappointed that
you did not buy a GEC machine� Why?’ Our reply was that the GEC
machine was more expensive and less efficient� There was no further
communication from Hogg on the project�
As Saiccor had never made a magnesium cook, or evaporated and
fired liquor, considerable research work was required to establish
operating parameters� This was undertaken by John Thubron and
Torgny Oehgren�
John Thubron, who had a chemistry degree with a further year to
bridge it to chemical engineering, joined Saiccor’s research laboratory
on 28 November 1974� Although he spent a brief period as Production
Manager in the mid 1970s, his forté was research� Over the years he
has done more research than anyone else into Saiccor’s entire process,
having established optimum temperature profiles for both calcium
and magnesium cooks, bleaching conditions (particularly with
oxygen), silica removal and calcium reduction, amongst other things�
John is a quiet man with a passion for long distance running – he has
run the Comrades many times – but tends to walk at a snail’s pace
deep in thought, hence Bruno Trevisan’s name for him, ‘Piede veloce’�
As the magnesium plant was the major focus of attention in 1983,
the low river flow went almost unnoticed until mid-winter� The
summer rains of 1982/83 had been very poor and by mid-May the
river flow had dropped to 50 cusecs (1,4 cumecs)� As the factory
requirement was just over 40 cusecs and as summer rains were only
due in September, the situation was uncomfortable� The earth weir
at the intake had again been built, impounding some 250 000 m 3 of
water, which was required when in mid-June the river flow dropped
to 40 cusecs for the next five weeks� On 24 July there were unexpected
rains and the river flow went back to 50 cusecs, keeping above 40
until the end of August when it again started to fall�
Ted Beesley arranged for well-points downstream of the weir to
pump water back over the weir, but their capacity was small� It was John Thubron
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