Improvements in the Manufacture of Artificial Manures.
Year: 1897

page_text: Improvements in the Manufacture of Artificial Manures.
I, Dr. WILHELM WOLTERS, of 9, Kaiserstrasse, Dresden, Saxony, German Empire,
do hereby declare the nature of this invention to be as follows:-
The present invention relates to the manufacture of artificial inanures, and has for
object to convert certain substances which are to be utilised as manure, into a state
in which they are most efficient in promoting the developement and growth of
plants.
These substances are the phosphorites in any suitable form (also bone materials),
the salts of the alkalies (sulphates), and the salts of the alkaline earths (sulphates
and carbonates). According to this invention I produce with these substances
compounds which are citrate-soluble, or compounds which are in part citrate-soluble,
and in part soluble in water, these compounds being most efficient for the purpose
according to the recognized principles relative to the nourishment of plants.
1. In the case of phosphorites, I melt them together with silicates of the alkalies
and of the alkaline earths. The alkali silicate to be used for this purpose may be
employed in the form of glass fragments, but silicates may also be employed, in the
production of which potassium salts (such as those found in Stassfurt) have been
used.
Silicates of the alkaline earths alone open up the phosphorites with considerably
greater difficulty than when silicates of the alkalies are also present.
With the former alone, also, the opening up or fluxing of the phosphorites
cannot be effected without loss of phosphoric acid. The double silicate of phosphor-
silicic acid, in which there are both groups of the bases, is more easily fusible and
produced than that which contains only bases of the alkaline earths. It is only by
using both of the substances referred to that there is obtained a high degree of
solubility in a citrate solution without loss of phosphoric acid, and I therefore
preferably employ both the silicates of the alkalies and the silicates of the alkaline
earths, but my invention includes the employment of the silicates of the alkaline
earths alone or the silicates of the alkalies alone, although, as I have already
explained, the result in either of these cases is not so satisfactory. The proportions
of mixture of the constituents to be melted together depend mainly on the
composition of the phosphorite employed.
With high-percentage phosphorites, a suitable proportion has been found to be
about 60 parts of silicate of the alkaline earths and 30 parts of alkali-silicate to
100 parts of phosphorite.
When, instead of soda silicate, potassium silicate is employed, as when Stassfurt
potassium salts are used, the quantity of alkali-silicate may be increased somewhat.
Slight variations in the composition are not of great influence. It is only when
there is a considerable percentage of magnesia that the addition of silicic acid
should be slightly reduced.
When glass is used, the desired proportions of silicic acid and the bases can be
produced by adding carbonate of lime.
The compound, which is soluble in a citrate solution, is only produced at a high

page_text: temperature at strong yellow heat when soda silicates are used, whilst a white heat
must obtain in the case of potassium silicates.
In working on a large scale, Siemens furnaces may be employed in which the
hearths are composed of the phosphoric acid-containing materials themselves, whilst
in operating on a small scale the mass can probably only be melted in a graphite
crucible.
As an example of manufacture on a small scale, the proportions of mixture may
be given, according to which the mass (citrate-soluble) was fused and gave
.extremely successful experiments in manuring.
In this case there were mixed
In carrying out the melting operation on a large scale, where the temperature
may be raised without risk of loss of phosphoric acid, because the mass does not
come in contact with organic matter as in the graphite crucible, considerably
more phosphorite may be treated with the same quantity of added substances.
2. With the alkali-salts (sulphates) and the salts of the alkaline earths (sulphates
and carbonates) it is necessary to melt them together with silicic acid (sand) at a
high temperature (white heat) in order to convert them wholly or partially into the
state in which they are citrate-soluble. The silicic acid compounds produced by this
melting process are no longer accompanied by the growth-hindering effects which
are often produced at times (for instance at the period of germination) by the
potash salts that occur therein.
The proportions of the constituents are not limited within very narrow limits
in order to give a good result; but it is advisable not to use too much sand, so
as not to reduce the solubility to too great an extent. Of course too little must
not be used, so as to convert the sulphates etc. to a sufficient extent into the
silicic acid compounds.
Suitable proportions for converting for example crystallized sulphate of potash-
magnesia into the active or operative silicic acid compound, have been found to
be as follows:-
100 parts of crystallized sulphate of potash-inagnesia,
25
22
"
» chalk,
" "
sand.
This mixture is melted in the furnace to white heat and after cooling is pulverized.
The mass is then suitable for direct use as a manuring agent.
Dated this 14th day of September 1897.
3
FFF
I, Dr. WILHELM WOLTERS, of 9, Kaiserstrasse, Dresden, Saxony, German Empire,
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 state-
ment :-
The present invention relates to the manufacture of artificial manures, and has for

page_text: object to convert certain substances which are to be utilised as manure, into a state in
which they are most efficient in promoting the development and growth of plants.
These substances are the phosphorites in any suitable form (also bone materials),
the salts of the alkalies (sulphates), and the salts of the alkaline earths (sulphates
and carbonates). According to this invention I produce with these substances com-
pounds which are citrate-soluble, or compounds which are in part citrate-soluble, and
in part soluble in water, these compounds being most efficient for the purpose accord-
ing to the recognised principles relative to the nourishment of plants.
1. In the case of phosphorites, I melt them together with silicates of the alkalies
and of the alkaline earths. The alkali silicate to be used for this purpose may be
employed in the form of glass fragments, but silicates may also be employed in the
production of which potassium salts (such as those found in Stassfurt) have been
used.
Silicates of the alkaline earths alone open up the phosphorites with considerably
greater difficulty than when silicates of the alkalies are also present.
With the former, alone also, the opening up or fluxing of the phosphorites cannot
be effected without loss of phosphoric acid. The double silicates of phosphor silicic
acid, in which there are both groups of the bases, is more easily fusible and produced
than that which contains only bases of the alkaline earths. It is only by using both
of the substances referred to that there is obtained a high degree of solubility in a
citrate solution without loss of phosphoric acid, and I therefore preferably employ
both the silicates of the alkalies and the silicates of the alkaline earths, but my
invention includes the employment of the silicates of the alkaline earths alone or the
silicates of the alkalies alone, although, as I have already explained, the result in
either of these cases is not so satisfactory. The proportions of mixture of the
constituents to be melted together depend mainly on the composition of the phos-
phorite employed.
With high-percentage phosphorites, a suitable proportion has been found to be
about 60 parts of silicate of the alkaline earths and 30 parts of alkali silicate to 100
parts of phosphorite.
When instead of soda silicate, potassium silicate is employed, as when Stassfurt
potassium salts are used, the quantity of alkali-silicate may be increased somewhat.
Slight variations in the composition are not of great influence. It is only when there
is a considerable percentage of magnesia that the addition of silicic acid should be
slightly reduced,
When glass is used, the desired proportions of silicic acid and the bases can be
produced by adding carbonate of lime.
The compound which is soluble in a citrate solution, is only produced at a high
temperature at strong yellow heat when soda silicates are used, whilst a white heat
must obtain in the case of potassium silicates.
In working on a large scale, Siemens furnaces may be employed in which the
hearths are composed of the phosphoric-acid-containing materials themselves,
whilst in operating on a small scale the mass can probably only be melted in a
graphite crucible.
As an example of manufacture on a small scale, the proportions of mixture may be
given, according to which the citrate-soluble mass was fused and gave extremely
successful experiments in manuring.

page_text: 2. With the alkali-salts (sulphates) and the salts of the alkaline earths (sulphates
and carbonates) it is necessary to melt them together with silicic acid (sand) at a
high temperature (white heat) in order to convert them wholly or partially into the
state in which they are citrate-soluble. The silicic acid compounds produced by
this melting process are no longer accompanied by the growth-hindering effects
which are often produced at times (for instance at the period of germination) by the
potash salts that occur therein.
The proportions of the constituents are not limited within very narrow limits in
order to give a good result; but it is advisable not to use too much sand, so as not
to reduce the solubility to too great an extent. Of course too little must not be
used, so as to convert the sulphates etc. to a sufficient extent into the silicic acid
compounds.
Suitable proportions for converting, for example, crystallized sulphate of potash-
magnesia into the active or operative silicic acid compound, have been found to be
as follows:-
This mixture is melted in the furnace to white heat and after cooling is,pulverised.
The mass is then suitable for direct use as a manuring agent.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The melting of phosphorites or bone-materials together with silicates of the
alkalies and of the alkaline earths, for the production of citrate-soluble phosphoric
acid compounds suitable for use as manure, substantially as herein before described.
2. The melting of the compounds (sulphates) of the alkalies, or the compounds
(sulphates or carbonates) of the alkaline earths, together with silicic acid for the pro-
duction of citrate-soluble silicic acid compounds suitable for use as manure, substan-
tially as hereinbefore described.
3. The improved manufacture of artificial manures, substantially as herein before
described.
4. As new products suitable for use as manures, phosphoric acid compounds and
silicic acid compounds such as are produced in the manner hereinbefore described,
the said compounds being citrate-soluble.
Dated this 14th day of June o
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.