DE103644C - - Google Patents

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IMPERIAL

ItÄff PATENT OFFICE.

PATENT LETTERING

CLASS 12: Chemical processes and apparatus.

Patented in the German Empire on May 23, 1897.

The previous proposals, bromine as such from alkalis containing bromine salts in solution, To obtain them by the electrolytic route, all proceed on the assumption that this is the case is only possible in such a way that the anode liquor can be separated from the cathode liquor by means of a diaphragm or some other device (see patent specification no. 30222 and 53395, class 12). ■

In this way one believes that one has to avoid that what has become free at the anode Halogen mixed with the hydroxide formed at the cathode and formed into halogenated oxygen salts implements.

In contrast, it has been shown that in the electrolytic separation of bromine from such alkalis, like those from the operations of the chlorinated potassium factories (Stafsfurl) resulting are composed, d. H. which in addition to predominant amounts of chlorides (especially Magnesium chloride) contain only small amounts of bromide (than magnesium bromide), the The use of diaphragms, which have very great disadvantages, is superfluous.

The experimental skuig used for the technical training of this process, the so-called. Final liquors from the potassium chlorine factories had the following composition: about 40 percent by volume Chiormagnesium, 0.5 to 1 pCt. Sodium chloride, 0.5 to 1 pCt. Potassium chlorine, 2 to 4 pCt. sulfuric acid Magnesia, 0.2 to o,: t pCt. Bromine, which is found in any case as magnesium bromine, this alkali is electrolyzed without it any device

to separate the cathode liquor from the anode liquor, whereby one rather The latter two can be mixed by appropriate circulation, so is this To conduct electrolysis easily in such a way that all bromine is released and also remains in such a state, without converting to bromine oxygen salts.

Only with too long exposure to the electric current, except for the bromides The chlorides are also broken down, creating halogen-oxygen compounds. The reason, The reason why the bromine does not react is that magnesium hydroxide is formed as the base which in and of itself is a weak base, almost insoluble in the lye and, lighter than the lye, the specific gravity of which is 1.34, on the latter as foam collects.

The decomposition of the lye can therefore take place in similar apparatus as it has been since then for the preparation of bleaching liquids are in use. While with the latter, however If a conversion to halogen oxygen salts takes place, the bromine remains in the free state dissolved in the lye.

The hydrogen appearing at the cathode escapes from the open decomposition apparatus into the open. The greater part of the released chlorine still settles with that in the lye Undecomposed magnesium bromine is converted into magnesium chlorine with the release of bromine. The freed bromine remains dissolved in the liquor and is then in a special one Distillation apparatus obtained by distillation

iz. Edition, issued on is. Octobe

Claims (1)

or can be in any other way, e.g. B. an air stream, also in a special one Separated from the lye. The decomposition apparatus had the following equipment: In a watertight, open Wooden boxes, inside 2 m long, 0.73 m wide and 0.5 m deep, were built in with carbon electrodes. The electrode walls were 70 cm wide, 25 cm. high and 1.5 inches thick. The walls passed from individual pieces, which were placed close together without any other connection. Only the parts of the first and last electrode wall were electrically conductive to each other, connected above by metal, and it became the one of those walls with the positive that others connected to the negative pole of the electricity source. The individual electrode walls worked accordingly after the Piincip of the so-called. Mittelehaltcrs by one side a Kk'ktnulenwniul the characteristics of a Cathode and the other showed those of an anode. The electrode walls were spaced apart of 1 3 mm and were in the interests of a complete .circulation of the lye irritating leaned against each side wall of the box, so that between it and the other side wall a margin of 3 cm remained. The lye to be decomposed ran its way between the individual electrode walls taking them through the box first into a container in which they are completely clears from the magnesium hydroxide foam, then, depending on requirements, into the stills to be drained. The decomposition is expediently carried out at a voltage of 3 to 3.5 volts, so that, as in the case of the experiment, at least 3 × 30 = 90 volts voltage was applied ^{with 1 ^ o electrode walls connected one behind the other.} At this voltage, the current yield, based on the bromine released, was 50 pCt. the theoretical, while it was significantly less when a lower voltage was applied. It is necessary to measure the amount of lye that flows through the decomposition apparatus in accordance with this power output. If too much lye flows through, there is no addiction sufficient bromine released when flowing through If the amount of lye is too small, bromine is lost through the formation of bromates. The success was independent of the temperature of the lye to be decomposed, since within the limits of 16 to 75 ^° C. the same ampere-hours delivered the same amounts of bromine, namely ι ampere-hour 1.5 g. With an alkali of 60 ° C. heat, the strength of the current and thus also the current density was about twice as great as with an alkali of 20 ° C. heat. It follows from this that success within these limits also depends on the current density. The current was at 20 ⁰ C. 25 to 30 Ampere and at 6o ° C. 60 to 65 amperes and the electrode area 17.5 the ^second In this process, the electrolysis is expediently carried out with the use of light lye, since in this case the warmth of the nhdistillirlen lye can be used, the original Preheat lye before it goes to electrolysis. It becomes an essential one Savings in heat achieved during distillation. The losses of bromine by evaporation here are so slight, that they were not mefsbar, although the boiling point of bromine is approximately 61 ⁰ C. The process is of course an uninterrupted one, in that the lye to be decomposed flows evenly through the decomposition box under constant voltage and current conditions. In this way it is possible to obtain a fairly chlorine-free product immediately. The bromine obtained was only 0.4. pCt. Chlorine. Pa τ ε ν τ - A ν s ρ u υ c η: Extraction of bromine from alkalis of the kind found in potassium chlorine factories result, d. H. which in addition to small amounts of ßromides essentially only contain chlorides, characterized in that that they can be used without the use of diaphragms and without any device for separating the anode liquor from the cathode liquor electrolyzed and then drives off the bromine.