METHODE POUR TRAITER LE MELANGE EAUX USEES-SOLIDES RESULTANT DE LA PRODUCTION DE PAPIER ET UTILISATION DE CE MELANGE DE SOLIDES

A METHOD OF PROCESSING THE WASTEWATER-SOLIDS MIXTURE THAT RESULTS FROM THE PRODUCTION OF PAPER AND THE USE OF THIS SOLIDS MIXTURE

Abrégé anglais

The present invention relates to a method of processing and re-
using the mixture of waste water and solids that is generated
during the processing of old paper, the sludge-like mixture of
water and solids being intensively mixed and then coarse, fine,
or very finely-ground, and it can then serve as the basic
material for the production, for example, of paint, glue, putty,
or mortar.

Revendications

The embodiments of the invention in which an exclusive
property or privilege is claimed are defined as follows.
1. A process for the preparation of a waste solids mixture
arising during the preparation of waste paper wherein said
solids are substantially composed of cellulose, kaolin and
calcium carbonate, said process comprising intensively
mixing the solids mixture to reduce the size of the solids
particles.
2. The process according to claim 1 further comprising adding
a suitable additive to the waste solids so that the waste
solids may be reused.
3. A process according to claim 1, wherein the solids mixture
is reduced by intensive agitation.
4. A process according to claim 1, wherein the solids
particles are finely ground.
5. A process according to claim 1, wherein the solids mixture
is dewatered before mixing and reduction.
6. A process according to any one of claims 1 to 5, wherein
the solids mixture is additionally supplemented with water
before mixing and reduction.
7. The use of the finely or coarsely ground solids mixture
prepared according to any one of claims 1 to 5, as a
base material for the production of colouring matter.

8. The use according to claim 7, wherein said colouring
matter is paint.
9. The use of the fine-ground solids mixture prepared
according to any one of claims 1 to 5, as a base material
for the production of an adhesive.
10. The use according to claim 9, wherein said adhesive is
glue.
11. The use of the finely ground solids mixture prepared
according to any one of claims 1 to 5, as a base material
for the 0production of filler.
12. The use according to claim 11, wherein said filler is
putty.
13. The use of the solids mixture prepared according to any
one of claims 1 to 5, as an additive for mortar or
plaster.

Description

- 2~56889
The present invention relates to a method of processing and re-
using the mixture of waste water and solids that results from
processing used paper.
During the production of paper, fillers are added to the pre-
product, i.e., chemical pulp, wood, straw pulp, or rag pulp or
old paper half stuff. These are intenAe~ to achieve a continuous
surface and to improve the whiteness of the paper.
When processing old paper in order to obtain the old paper half
stuff that is necessary for the production of paper, these
fillers, which are added in their turn to this old paper during
the production of paper, occur as waste product. This waste
product consists, for example, of 50%-wt cellulose, 25%-wt
kaolin, 20%-wt calcium carbonate, as well as small amounts of
gypsum, titanium oxide, and other solids.
During the methods that were previously used to process old paper
the method was such that these waste substances were removed from
the process as a mixture of waste water and solids. Up to now,
this has involved a pure waste product that consists of
approximately 50%-wt water and approximately 15%-wt of solid
substances that was then stored in dumps. The processing of this
waste product, so as to render it fit for this type of storage,
is costly. In addition, there are costs involved for
transporting this waste product and finally, one has to consider

20~68~9
the dumping costs, for this waste product is not, for example,
suitable for the earth dams used for safety embankments.
Some 100,000 tons of this waste product are generated each year
in Holland, and this consists of 50%-wt solids and up to 50%-wt
water.
The journal Das Papier ~Paper], 26/1972, reports on the disposal
of the residual waste water sludge and adds that although the
problem of separating the sludge water is considered as solved,
the question of disposing of the sludge has not yet been
resolved. Reference is made to the fact that during normal paper
production, the residual waste water sludge can be used, for
example, in brickyards as opening material in order to produce
porous bricks, or that fireproof fibres can be extracted from the
residual water sludge. Composting has also been employed as a
way to reuse the sludge.
Wochenblatt fur papierfabrikation ~The Paper Production Weekly],
23/24, 1977 describes the reuse of ashes generated by waste water
sludge.
The processing of the waste water sludge that occurs when old
paper is processed has not as yet been described.

4 ~C) 5b ~f~)l
It is the task of the present inventlon to descrlbe a way of
reuslng thls waste product.
In order to solve thls task, whlch forms the basls for the
present lnvention, lt is proposed that the sludge-like water-
solids mixture is first intensively mixed and that then this
mlxture of water and solid is coarsely, flnely, or very finely
ground.
The present invention provides a process for the preparation of
a waste solids mlxture arlslng during the preparatlon of waste
paper whereln sald solids are substantially composed of
cellulose, kaolin and calcium carbonate, said process
comprising intenslvely mixing the solids mixture to reduce the
size of the sollds partlcles. The waste sollds may be reused
by adding a suitable addltlve to the waste solids. For
example, in order to produce paint, addltlves such as acrylate,
titanium whlte, chalk, gypsum, ammonla and water may be used.
The mlxture of the sludge-llke sollds mlxture ls necessary, for
when it ls generated thls waste mlxture has not been
intenslvely mixed but can conslst of very dlfferent solid
lentils or solid conglomerates. The product has to be reduced,
for a large number of fibre-like components are contained ln
the sludge-llke solids mixture and these components preiudice
subsequent re-use of the product. The product that ls elther

~o s~
4a
fine-grained or coarse-grained, depending on lts intended use,
can be obtained by appropriately metered reductlon of these
fibre-like components.
The mixture of water and extremely fine particles of solids
that is obtained in this manner can then be used as the
starting substance for the production of various materials such
as paint, glue, putty, or mortar. An important feature of this
starting material are its thixotropic properties, which make it
particularly suitable for the production of the substances
enumerated above.

20~6889
As an embodiment, reference can be made to the fact that in order
to produce paint one proree~C from the mixture of extremely fine
solid particles according to the present invention, acrylate,
titanium white, chalk, gypsum, ammonia and additional water being
added to this mixture of extremely fine solid particles. The
coarsc ~L ained mixture can be used as a starting substance
deFDn~ing on the type of colour and, in particular, when it is
used for a mortar.
Tests made with paint produced in this manner have shown that it
is equal to all the demands made of modern paints that are
applied by brushing, so that the appropriate re-use of the
product, which can be regarded as a waste product, has been
achieved.