DE254544C - - Google Patents

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- M 254544 CLASS 12 /. GROUP fr /.

Process for opening up alkaline silicate rocks by means of patented in the German Empire from May 24, 1911.

CHEMICAL FACTORY RHENANIA in and Dr. ANTON MESSERSCHMITT in STOLBE

When causticizing the soda with quick lime or when carbonizing the Leblanc process Resulting calcium sulfide according to Chance-Claus arises as a by-product a sludge, which essentially consists of carbonate of lime.

This sludge contains up to 50 percent of its weight in water, which is so solid that it is stubbornly "held back" even when suction filters are used will. Drying experiments have proven to be technically difficult and therefore difficult to carry out proved too costly.

Due to the high water content and other unpleasant properties of the The multiple attempts to utilize this sludge have practically no sludge Successes in time or only in exceptional cases' under special local conditions, such as very high lime prices, any meaning.

The burning of the fine material to quick lime first requires the expulsion of the large amounts of water, i.e. consumption of fuel; also can be the same because of the physical condition of the material only due to the relatively expensive rotary kiln operation take place. ·

The processing on cement is only possible after a pre-treatment to remove the Sulfur and other compounds possible.

In some plants that manufacture Leblanc soda, part of the sludge is used as Substitute for limestone was added to the mixture for the soda melt, however, the Reusing larger amounts for this purpose ■ has proven to be disadvantageous, on the one hand because of the water content, on the other hand because of the resulting accumulation of impurities in the melt. Even There is practically no recovery of the alkali still contained in the sludge in the apparition.

One has finally tried to sell the sludge as a fertilizer, but this recovery has due to the alkalinity and the high water content, the again high transport costs as a result, as well as for other reasons, has only very local significance.

The sludge thus represents a very low value, by and large complete worthless waste product, which due to the lack of recycling possibilities of most Operated on the dump and is gradually thrown there in immense masses accumulates.

The invention is a method which consists in this sludge usable for the extraction of alkali compounds from alkali-containing silicate rocks do.

In the practice of the method one proceeds, for example, that one of the sludge incorporated the silicate rocks to be treated in powder form. You get one like that plastic mass, which continues until the silicate powder is evenly distributed

is kneaded. By calcining the product thus obtained, the alkalis or alkali compounds become split off and obtained by leaching.

It is already known that alkaline silicate rocks such as feldspars, mica, Leucite, phonolites, trass, etc., the alkalis by glowing with lime or limestone split off.

ίο Compared to this known method, the present one offers very considerable new technical advantages.

For example, if you want to use lime or limestone, you have to use them first Grind to a fine powder, which is then ground with the powdery Silicate rock is mixed. The expense of the large amounts of lime required, too who still pay the considerable cost of the extremely fine marriage but the process itself is so expensive that it cannot be carried out in practice; because the alkali compounds obtained by this process would be considerably more expensive like the Staßfurt salts.

When using the lime sludge according to the present invention, the applied costs Lime almost nothing, and furthermore the cumbersome and costly grinding process is completely eliminated because the effective one Carbonate of lime is already present in as fine a form as it is through precipitation Grinding could never be achieved. It is also in the finest distribution at the same time with such a content of water in the sludge product that after Incorporation of the silicate powder readily forms a plastic mass of such a nature the result is that it is not only mixed and kneaded completely evenly using a suitable machine, but also in suitable forms, e.g. B. briquettes or strands can be brought.

As a result of the fineness of the carbonate salts and. the even distribution of the same

Claims (2)

Patent claims: in the mass the advantage is achieved that there is a considerable increase in the application of alkalis compared to the use of ground limestone. Since the sludge resulting from causticizing the soda or the chance process contains not inconsiderable amounts of soda, the advantage is also achieved that this soda, which has since been completely worthless, has a partly beneficial effect on the breakdown of the silicate and that it is partly recovered can. It has surprisingly been found that the other products and impurities present in the lime sludge do not interfere with the process. For example, the sulfur still contained in the chance sludge remains largely bound to lime when the annealing product is leached, so that it does not exert a harmful effect Large amounts of carbonate of lime fall off, while on the other hand the task of obtaining alkali salts from alkali-containing silicate rocks in an economically viable manner has been successfully achieved for the first time. 1. Method for breaking up alkaline silicate rocks by means of lime, thereby characterized that for this purpose the manufacture of the caustic soda or Lime sludge falling off in the Leblanc soda process or similar processes Is used. 2. The method according to claim. 1, characterized in that the lime sludge Silicate rock to be digested is incorporated in powder form, whereupon the thus obtained plastic mass is annealed.