DE313827C - - Google Patents

Description

GERMAN EMPIRE

"ν-« ^Λ

ISSUED ON JULY 22, 1919

REICH PATENT OFFICE

PATENT LETTERING

JVi 313827
CLASS 12 k GROUP 6

If one leads into a strong ammonia solution, "for example salmiakgeist of 0.91 spec. Wt. While cooling, add carbonic acid until Λ the liquid does not smell noticeable Shows more ammonia, it is well known that by far the greatest part of ammonia falls into Form of crystalline ammonium bicarbonate, which in a known manner by means of a salt filter, drum filter, a Nutsche or centrifuge from the attached mother liquor, which from a concentrated Solution of the salt consists, can be freed. In this state, however, contains that Ammonium bicarbonate, at best, still

t5 5 percent adherent moisture. Dries the salt, which at a temperature of 60 ° with splitting off of carbonic acid, later from ammonia and carbonic acid, begins to disintegrate, carefully, be it on one Steam kiln, in a vacuum dryer or in some other way, that's how you are anyway unable to prevent carbon dioxide loss. Parts of it will always escape which causes the formation of ammonium sesquicarbonate, which has a very noticeable smell of ammonia, therefore also loses considerable amounts of it when it is stored. To avoid this, an aftertreatment takes place first carbonated instead.

It is well known that ammonium carbonates are converted into bicarbonate by treatment with carbonic acid over, whereby an essential requirement is the presence of a certain amount of moisture. So you wild that Wet salt, as it comes from the salt filter, as good as it will go, on one of the mentioned Dry the drying apparatus as carefully as possible, taking care that any ammonia that escapes is free of loss can be caught.

In the sense of the information given, drying is not to be continued so far, that all adhering water escapes; rather, precaution must be taken that im Dry product no matter how much water remains that its amount is sufficient to withstand the the drying partially formed ammonium sesquicarbonate in the presence of carbonic acid to be able to react under .bicarbonate formation. ν

One can also proceed in such a way that the drying is carried out completely in the dry product the amount of the sesquicarbonate formed is determined analytically and the amount arithmetically adding the required amount of water by sprinkling, although this process appears to be easier to carry out in an accurate manner is, experience has shown that it is extremely easy to do the first described purely emotionally practically to be carried out, which then deserves the preference. .

If the salt prepared in this way is treated with carbonic acid, the following reaction occurs:

NH ₄ HCO ₃ (NH ₄ ) ₂ CO ₃ + H ₂ O + CO ₂ = 3NH ₄ HCO ₃ .

However, this complete carburization is necessary

to terminate it at the usual pressure of the carbonic acid used for this purpose very considerable time, especially if "~ it is it is therefore a matter of passing through larger "herigen" or compact, coherent masses of salt and to carburize through. According to another method of drying ammonium bicarbonate, the centrifuged salt is treated in a closed agitator

ίο with ammonia and carbonic acid, which with an overpressure of ¹ ^. Atm. are fed. This pressure is in itself insufficient to ensure the contact of every salt particle with the gases, and therefore stirring must be carried out, which requires complicated apparatus. The perception was also made that the bicarbonate produced in this way is not particularly stable, but rather loses carbonic acid again easily.

ao. According to the present invention, Avoid both (! assistants through the working method described below:

The treatment with carbonic acid has to be done in such a way that the from Dryer coming salt of the above-mentioned nature in a tightly lockable A vessel about a pressure vessel, enters • and carbonic acid under 2 to 3 atmospheres. pressure after previous displacement of the air contained in the vessel, pumped up. To Briefly standing under pressure, if necessary pumping up carbon dioxide, proves to be the entire contents of the pressure barrel as completely odorless, permanent ammonium carbonate.

The use of a pressure of a few atmospheres has been found according to the invention as essential to shorten the response time

and has been shown to produce consistent bicarbonate. .

In order to further increase this resistance, the described method of operation was also used still set up as follows:

The decomposability of ammonium bicarbonate is, among other things, a function of the surface of the salt. To do this as much as possible You can reduce the salt before drying or before treating the dried Carbonated salt, or after these operations by means of a briquette press Use of a correspondingly high pressure to press bricks, which is then practically unlimited are durable. · These briquettes nonetheless have the property of a relatively low pressure, e.g. B. that of a pair of rollers in a crystal powder disintegrate. .

Claims (2)

Patent claims: 1. Process for, production of ammonium bicarbonate in odorless, permanent, loss-free storage form by carefully drying the crystalline precipitated bicarbonate and post-treatment of the dried bicarbonate in an appropriately moistened state .Carbonated, characterized in that this post-treatment with carbonic acid .: takes place under a pressure of a few atmospheres. 2. The method according to claim 1, 'thereby ■.,. characterized that the ammonium bicar, ' bonat for the purpose of reducing its surface area, before or after drying, before or after the aftertreatment with carbonic acid, is briquetted. : \.;