A Process and Apparatus for the Manufacture of Nitrated Starch.
Year: 1890

page_text: Date of Application, 16th Sept., 1890-Accepted, 18th Oct., 1890
COME LIMEIE DIMITTUATION.
A Process and Apparatus for the Manufacture of Nitrated Starch.
I, WILHELM SCHUCKHER of No. I Hegelgasse 13, Vienna in the Austrian Empire
Manufacturer, do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement :-
My invention relates to the manufacture of nitrated starch, a substance which may
be advantageously used instead of nitrocellulose as an absorbent of nitroglycerine and
other liquid explosives. As raw material, I prefer to use potatoe starch on account
of its cheapness and uniform character, but other starches may be employed. I dry
the starch at a temperature of about 100° C. and grind it finely. I then dissolve it at
a temperature of 20° to 25° C. in nitric acid of 1.501 specific gravity, using about
10 kilo. of acid to each kilo. of starch. The solution is then mixed with a quantity of
mingled sulphuric and nitric acids, which for the sake of cheapness may be the waste
acids from the nitroglycerine manufacture, these being equivalent in effect to fresh
acids. These waste acids, containing about 70 per cent. sulphuric acid monohydrate
and 10 per cent. nitric acid monohydrate, are used in the proportion of about 5 kilos.
to each kilo. of the nitrated starch solution, which is thoroughly agitated with the
acids at a temperature of 20° to 25° C. The nitrated starch is precipitated in a very
finely subdivided condition and is collected on a filter of gun cotton through which
the acids pass.
After filtration the nitrated starch is freed from residuary acid by
pressure in a hydraulic press producing cakes which are well agitated and thoroughly
washed in water. About 5 per cent. of soda solution is then added, and after about
24 Lours the material is ground by rollers, producing a creamy liquid which is
dehydrated in a centrifugal machine or filter press and is finally impregnated with
aniline to fix the nitrated starch, the proportion being about 1 per cent. of aniline to
nitrated starch holding about 33 per cent. of water. Apparatus for carrying out the
process above described may be variously constructed. Fig. 1 of the accompanying
drawings is a vertical section of a convenient apparatus for effecting the solution of
the starch, and Fig. 2 shews apparatus for its precipitation. A and B Fig. 1 are two
jackets through which cooling water is caused to circulate from the inlet at a up A
and down B to the outlet c. On a central shaft is fixed a helical propeller C which
keeps the contents of the vessel in active circulation as indicated by the arrows,
down D, between ceramic supports d, up Z and between the connecting tubes b.
As shewn in Fig. 2 the precipitating vessel A is surrounded by a jacket M through
which cooling water circulates from the inlet a to the outlet c.
Near the bottom there is a double sieves s' with an intermediate layer of gun
cotton. When precipitation is completed, the cock his opened allowing the acids to
flow out, while the precipitate is retained on the filter s. The cover is provided
with glazed sight-holes so that the internal action can be observed. The solution of
nitrated starch is admitted from the pipe n by an atomiser a supplied with a current
of compressed air from the pipe m.
The nitrated starch produced as above described dissolves readily in nitroglycerine
and its analogues, and can be mixed in any proportions with nitrocellulose. When
the nitrated starch is dissolved in cold nitroglycerine, the mixture is first a mass
resembling lime, but as more of the nitrated starch is added, the mixture becomes of a
hard waxy character..
Nitrated starch in compressed condition pure or mixed with nitro-cellulose or with
nitric or chloric salts, or saturated with nitro-glycerine, is available for many purposes
connected with explosives.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is
The herein described manufacture of nitrated starch by dissolving dried and ground
starch in nitric acid, precipitating in finely divided condition in mixture of sulphuric
and nitric acids, drying, washing, and roll grinding the precipitate and adding aniline
thereto.
Dated this 16th day of Santambar 1800
ABEL & IMRAY,
Agents for the Applicant.