US1193794A - Adalbert kolb - Google Patents

Description

=scription of the same.

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ADALIBERT KOLB, 0F CHARLOTTENIBURG-WESTEND, GERMANY, assrenon TO HE rnnmn'rrr COMPANY, on NEW YORK, n. Y.

PROCESS OF PRODUCING GHBOMIUM-CONTAINING SILICATES. I

1,193,794. No Drawing.

To all whom it may concern:

Be it known that I, ADALBERT KOLB, proat No. 6 Leistikowstrasse, Charlottenburg- Westend, near Berlin, German Empire, have invented new and useful Improvementsin Processes of Producing Chromium-Containing Silicates; and I do hereby declare the following to be a full, clear, and exact de- In technical literature it is stated that base exchanging chromium-containing silicates cannot be produced (compare Gmelin= Kraut: Text Book of Inorganic Ukemistry, 7 edition, Volume III 1, page 1314, or F. Singer: On Artificial Zeolites, Dissertation at the Technical University, Berlin, 1910, ex-

periment 27, pages 3637 and page 45.) Further it is said that by melting together suitable quantities of sodium oxid, chromium oxid,'silicic acid, a' glass like product is obtained, which, when lixiviated with water, forms a slime, which has not a base exchanging property (see Gmelin-Kraut, same volume, page 1392, or Singers Dissertation, page 36). According to these authorities there is no possibility of obtaining base exchanging silicates containing chromium, and from a theoretical standpoint there is no reason to take the opposite view, because in the chromites the alkali is butloosely united and chromium does not form a simple compound with silicic acid (see Gmelin-Kraut above).

Now it has been found that, contrary to previous experience, base exchanging silicates containing chromium can be obtained, and indeed from alkaline chromite salt solutions, by adding alkali silicate. In doing so it is necessary to avoid a considerable excess of free alkali, not to dilute the solutions too much, and to work without heating the same. In order to convert the precipitate into a granular, hard and solid form suitable for technical purposes, said precipitate, when decanted, is washed (a small residue of free alkali being purposely left therein) then pressed, dried and the hard material or press cake obtained is introduced into hot water. The hot mass breaks up with a loud crackling sound into green, or dark green,

coarsely granular, crystal pieces which cons1st of sodium oxld, chromium oxid, silicic Specification of Letters Patent.

' Patented Aug. 8, 1916.

acid and water, and, in addition to their base exchanging property, are characterized by hardness and high resistance to hot water and cold acids.

According to the described process it is possible to obtain not only silicates containing chromium, but also other analogous-compositions having like properties, if, instead of chromium 'salts, or in lieu of or in addition thereto, there are used solutions of other alkali soluble oxide of more or less' acid properties, such as the oxids or boron, vanadium, tungsten, etc. Further, it has been found that the salt solutions in question need not be pure, but that mixtures of chromite silicates and the like containing these or other base exchanging bodies such as alumina, in greater or less proportion can also be produced, and that the mixed products obtained also have a high resistance to mechanical strains and chemical reagents. Such mixed exchange silicates are produced by precipitating mixtures of chromium solutions, etc., with aluminate solutions, etc., by means of corresponding quantities of silicate'solutions and by drying the deposits obtained and treating the same with hot water. Instead of previousl making the alkaline solutions of these su stances, mixtures of non-alkaline chromium salt solu tions, etc., with solutions of other suitable salts, for example aluminium, zinc, lead, etc., salts can be precipitated by the requisite amount of silicate solution containing suflicient alkali to neutralize the acid of such salt solutions.

In a typical embodiment of my process 38 parts by weight, as for example, 38 kilograms, of chrome potash alum (or corresponding quantities of chromium sulfate or otherchromium salts) are dissolved in 200 liters of water and the solution is shaken and introduced into 33 liters of technical soda lye of 395 Baum diluted with the same volume of Water, that is into the quan-- posit formed is washed, pressed and dried ata temperature below 100 C. As a consequence a dark green, granular mass is obtained, which, when washed with hot water, decomposes and forms a hard, uniformly coarse, granular product.

In another embodiment, 19 kilograms of chrome alum (or a corresponding quantity of other chromium salts) and 12.5 kilograms aluminium sulfate are dissolved in 150 ln'lograms of water, and the solution is introduced into such a quantity of soda lye that the hydroxids first precipitated are again dissolved, and the solution still remains clear when diluted. The mixture is then brought to about 500 liters by adding water, and while stirring same it is mixed with the corresponding quantity of diluted water glass solution (about 30 kilograms of 39 Baum solution). After stirring the same for some time the precipitate is washed, dried and treated with hot water.

In still another embodiment, 19 kilograms of chrome alum (or a corresponding amount of other chromium salts) and 14.5 kilograms of zinc sulfate are dissolved in 500-750 liters of water, and the solution is then mixed with a mixture of 36 kilograms of water glass solution (of about 39 Baum), 50 1iters of soda lye (40 Baum) and 50liters of water and well stirred. The precipitate obtained is then treated as above set forth.

The base exchanging chromite silicates or other analogous metal silicates of high chemical resistance can be used in the same manner as exchange silicates or artificial zeolites, for purifying water, for removing undesirable salts from solutions, for producing new salts by base exchange, etc., but they are superior to the alumina-containing silicates heretofore used for the same purpose owing to their great hardness and corporated catalytically acting metal oxids by treatment with metal salt solutions, in which case materials are obtained, which are particularly suitable for carrying out cata--' lytic processes of all kinds and especially for carrying out oxidations in aqueous solu- 'tions.

What I claim and desire to secure by Let- 'ters Patent of the United States is 1. The process of producing exchange silicates which comprises precipitating a so lution containing chromium with an alkaline solution containing dissolved silica and washing and drying the precipitate.

2. The process of producing exchange silicates which comprises precipitating an alkaline solution containing chromium with an alkaline solution containing dissolved silica and washing and drying the precipitate.

3. The process of producing exchange silicates which comprises precipitating a solution containing chromium with an alkaline solution containing dissolved silica and washing, pressing and drying the precipitate.

4. The process of producing exchange silicates which comprises precipitating an alkaline solution containing chromium with an alkaline solution containing dissolved silica and washing, pressing and drying the pre-