OF THE DOUBLE ALUMINUM AND AMMONIUM SULPHATE
IN THE PAPER
Rios Pita Giurfa
In the nineteenth
century paper manufacture industry used natural aluminum ammonium
sulfate , the mineral known as "Tshernigite", or the
other natural alum, double aluminum and Potassium Sulfate.
When the Bayer
process for the extraction of aluminum from bauxite appeared, it
began to be used the artificially obtained Aluminum Sulfate
We all know that
books from the 18th.century, made from natural alum,
are extraordinarily well preserved in libraries book shelves, in
contrast with those books made from papers obtained with the use
of simple aluminum sulfate.
As it is well known
double aluminum sulfates are made from simple aluminum sulfates,
then logically are more expensive than the simple ones.
In 1986 it was
found at Cerro Verde Mine ( a copper mine ,located at the south
of Peru, then state owned, and where solvent extraction methods
were applied for the extraction of copper from acid leaching
liquors of copper oxides ) that the content of aluminum in the
"raffinate" liquors was as high as 12 grams per liter
and this was interfering with copper extraction efficiency. Then
it was proposed to separate this aluminum precipitating it as double
aluminum and ammonium sulfate using ammonia for this purpose.
We then suggested the use of the fertilizer ammonium sulfate to
attain this goal, since it was cheaper and it was not needed to
build a plant for the production of ammonia.
A pilot plant was
constructed and the product obtained in this plant was being
sold, through a dealer, to local paper manufacturers. This plant
was closed before the mine was privatized, and stopped producing
the aluminum-ammonium double sulfate.
The aim of this
page is to call the attention to what was found in the actual
application of the double aluminum sulfate in the paper industry.
It was found the
- Double sulfate was used in
30% less per each ton of paper compared to simple
- Drying of "stock"
was accelerated , then saving steam energy expenses.
- Fiber dispersion was even.
- Paper impermeability to water
was considerably increased.
Since this plant
closed the dealer was deprived of this product and contacted us
to obtain it; but not having access to the same cheap source of
aluminum we sought and found another cheap source: the effluents
of an activated clays factory. But we really used a simple
aluminum sulfate recovered by this company, and to obtain it at
the cheapest cost we obtained the double aluminum and ammonium
sulfate through a "DRY REACTION", by mixing dry
aluminum sulfate and ammonium sulfate in an helicoidal mixer with
the stoichiometric amount of water, as follows:
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