DE169292C

DE169292C -

Info

Publication number: DE169292C
Application number: DENDAT169292D
Authority: DE

Description

KAISERLICHESIMPERIAL

PATENTAMT.PATENT OFFICE.

Die vorliegende Erfindung besteht in einer weiteren Ausbildung des durch das Patent 155806 geschützten Verfahrens zur Gewinnung von Ferrocyannatrium aus einer dieses und Chlorcalcium enthaltenden Lauge, welche mit Hilfe von Chlornatrium aus Ferrocyancalcium gewonnen wird. Im genannten Patente ist auch der Weg gezeigt, wie man durch Abkühlenlassen der in der Wärme entstehenden Lauge von Ferrocyannatrium und Chlorcalcium das erstere verhältnismäßig leicht aus der Lauge durch Auskristallisieren gewinnen kann.The present invention consists in a further development of that disclosed by the patent 155806 protected process for the production of ferrocyan sodium from this and lye containing calcium chloride, which is obtained from ferrocyanine calcium with the aid of sodium chloride is won. In the patents mentioned, the way is shown how to cool the resulting in the heat Lye of ferrocyan sodium and calcium chloride the former proportionally can easily be obtained from the lye by crystallization.

Was das alsdann weiterhin beschriebene Abscheiden des Ferrocyannatriums durch einfache Konzentration der Mischlauge anbelangt, so ist in diesem Falle, wie gemäß vorliegender Erfindung festgestellt wurde, der aus der Lauge gewonnene NiederschlagWhat the then further described deposition of ferrocyan sodium by As far as simple concentration of the mixed liquor is concerned, in this case it is as in accordance with The present invention was found, the precipitate obtained from the liquor

ao ein Doppelsalz, nämlich Ferrocyannatriumcalcium, und nicht, wie in dem Buche der Erfindungen, Gewerbe und Industrie Band VII (1899), S. 346 angegeben ist, Ferrocyannatrium in Form eines wasserfreien Pulvers.ao a double salt, namely ferrocyan sodium calcium, and not, as in the book of the Inventions, trade and industry Volume VII (1899), p. 346 is indicated, Ferrocyannatrium in the form of an anhydrous powder.

Dieses Ferrocyannatriumcalcium muß alsdann, um das Ferrocyannatrium zu erhalten, selbstverständlich erst wieder umgesetzt werden.This ferrocyan sodium calcium must then of course in order to obtain the ferrocyan sodium only to be implemented again.

Beide Verfahren, jedes für sich, geben in bezug auf die wirtschaftliche Ausbeute nicht ganz das erwünschte Resultat, Es wurde nun im Verlauf von Versuchen weiterhin gefunden, daß man eine sehr günstige Ausbeute an Ferrocyannatrium auf wirtschaftlich vorteilhafte Weise dann erzielen kann, wenn man die besagten beiden Operationen unter gewissen unten näher angegebenen Maßnahmen miteinander verbindet, wobei noch die ebenfalls früher nicht gemachte Beobachtung, daß sich das Doppelsalz Ferrocyannatrium-Both processes, each for themselves, do not give in terms of the economic yield quite the desired result. It has now been found in the course of experiments that one can obtain a very favorable yield on ferrocyan sodium can then achieve in an economically advantageous manner if the said two operations under certain measures specified below connects with each other, whereby the observation, also not made earlier, that the double salt ferrocyan sodium

calcium Fe (C N)₆ γΑ in technisch und wirtschaftlich zufriedenstellender Weise in Ferrocyannatrium umsetzen läßt, ausgenutzt wird. Das Verfahren besteht in folgendem:
Die mit der entsprechenden Menge Chlornatrium versetzte Ferrocyancalciumlösung wird unter gewöhnlichem Druck so lange eingedampft, bis sie beginnt, das Doppelsalz Ferrocyannatriumcalcium auszuscheiden; alsdann wird mit dem Konzentrieren fortgefahren, aber bei einer Temperatur, die wesentlich niedriger ist unter Benutzung eines Vakuums. Hierbei löst sich das bereits ausgefällte Doppelsalz Ferrocyannatriumcalcium wieder auf, und es entsteht nebenbei auch eine weit konzentriertere Lösung von Ferrocyannatrium. Die Erklärung dafür ist, daß das Doppelsalz nur bei niederer Temperatur in Lösung bleibt, dagegen bei höherer Temperatur ausfällt. Das bei niederer Temperatur in Lösungcalcium Fe (CN) ₆ γΑ can be converted into ferrocyan sodium in a technically and economically satisfactory manner, is exploited. The procedure consists of the following:
The ferrocyanealcium solution to which the corresponding amount of sodium chloride has been added is evaporated under normal pressure until it begins to precipitate the double salt of ferrocyanodium calcium; then concentration is continued, but at a temperature which is much lower using a vacuum. The double salt ferrocyan sodium calcium which has already precipitated out dissolves again, and a far more concentrated solution of ferrocyan sodium is also formed. The explanation for this is that the double salt only remains in solution at a lower temperature, whereas it precipitates at a higher temperature. That at low temperature in solution

Claims

The double salt held here tends to convert into Ferrocyannatriuni and Ferrocyancalcium, which are more soluble than the double salt itself; from this it follows that, as noted above, a far more concentrated solution of ferrocyan sodium is found in the alkalis treated in vacuo. When the operation has progressed so far, the lye is drained and cooled; Ferrocyan sodium then separates out of it in considerable quantities and in beautiful large crystals. The remaining mother liquor is again evaporated in vacuo at a temperature of about 60 ° until it has assumed such a degree of concentration that it begins to precipitate double salt in solid form even at the lower temperature mentioned. ao Then it is drained again, separated from the precipitated double salt by decanting and then cooled. This leads to a further separation of ferrocyan sodium in beautiful crystals. The now remaining caustic is then heated to a temperature at which the ferrocyan still present in the caustic separates out as a double salt. This excretion is made technically complete by the further concentration associated with the heating. The mother liquor of calcium chloride, which has now become worthless, is drained off, and the double salt obtained by the above-mentioned operations is dissolved in the warmth with the addition of sodium chloride to form a concentrated liquor with water. The temperature is to be kept so that it does not exceed the degree, about 60 to yo °, which allows the highest possible concentration of the lye. Exceeding a certain temperature leads to a renewed deposition of the double salt in the case of the substances in question. The lye obtained in this way is cooled and ferrocyan sodium is obtained in beautiful crystals. The remaining mother liquor is used to dissolve a new amount of double salt as in the last-mentioned operation. Finally, it becomes so enriched with calcium chloride that it can no longer be used to obtain ferrocyanic sodium and is therefore returned to the overall process with the raw liquor. The very smooth conversion of the ferrocyanealcium sodium double salt with chlorine sodium, described at the last point, makes it possible to produce the ferrocyane sodium. can also be obtained by converting all of the ferrocyane contained in the raw liquor into the double salt, separating it as such from the liquor and then reacting it with sodium chloride. The use of the vacuum can also be dispensed with under certain circumstances; but it serves essentially to make the process run smoothly and comfortably. If the vacuum is not applied, so that the lye is heated to a higher degree, the desired result can still be obtained by changing the concentration ratios accordingly. The double salt ferrocyan sodium calcium Fe (C NJ6 -jr ^ offers the double salts ferrocyan potassium calcium and ferrocyanammonium calcium over the advantage that, in contrast to these, it is extremely soluble in water, decomposes in this solution below the temperature of 60 to 700 for the most part and that by Addition of sodium chloride to this solution, ferrocyan sodium can easily be obtained by crystallization by means of cooling. Due to this very different behavior, the conversion of ferrocyanic calcium into ferrocyan sodium can be accomplished entirely by means of the cheap sodium chloride, completely avoiding the use of the significantly more expensive carbonate of sodium hey:

1. The one protected by patent 155806 Process for the production of ferrocyan sodium from a ferrocyan calcium solution, modified so that for the purpose of achieving a technically and economically more advantageous yield Ferrocyanatrium the ferrocyanealcium lye mixed with sodium chloride first up to at the beginning of the deposition of the double salt ferrocyan sodium calcium in ordinary Way and then at low temperature (advantageously using a vacuum) under intervening Cooling and crystallization of the ferrocyan sodium formed in each case evaporates until the lye is solid Ferrocyane calcium sodium precipitates, from which it is separated, whereupon one < the remaining lye is cooled for the purpose of crystallizing out any ferrocyan sodium that is still present.

2. The transfer of the obtained in the method according to claim 1 Double salt in ferrocyan sodium in such a way that you get the double salt at increased Temperature with the addition of sodium chloride to a con-iao as possible centered lye dissolves in water and releases. the lye by letting it cool

Ferrocyanodium crystallizes out, whereupon the remaining mother liquor in the process can be traced back.

3. The process for the production of ferrocyan sodium, protected by patent 155806 from a ferrocyanic calcium solution, modified so that the ferrocyanic calcium solution to which sodium chloride has been added evaporated in the usual way until the complete separation of the ferrocyan as ferrocyan sodium calcium and this double salt then characterized in de / in the preceding claim 2 Way further processed.