US1319918A - Limestone into compressible artificial stone - Google Patents

Description

UNITED STATES PATENT orrrcn.

CARL LUDWIG VALENTIN ZIMMER, OF BEBLIN-WILMEIBSDOBF, GERMANY, ASSIGNOB, BY MESNE ASSIGNMENTS, TO THE CHEMICAL FOUNDATION, INC., A CORPORATION OF DELAWARE.

PROCESS FOR CONVENTING- LIMESTONE INTO COMPRESSIBLE ARTIFICIAL STONE.

No Drawing.

To all 'whom it may concern:

.Be it known that I, CARL LUDWIG Vanni:- TIN ZIMMER, doctor of philosophy, 9. subJect of the King of Prussia, and a resident of Berlin-\Vilmersdorf, No. 30/31 Pariserstrasse, Germany, have invented new and useful Improvements in Processes for Convertin Limestone into Compressible Artificial tone, of which the following is a specification.

Heretofore no process was known for producing an artificial stone which has the property of decomposing to a powder when heated, and of regaining its original hardness under pressure.

Only natural asphaltic limestone, as found at but a few places on the earth in limited quantities, has the specially characteristic property that, when heated to 1'50200 (3., it decomposes to a brown, loose powder which can be compressed by pressure to the hardness of the original stone. Owing to these properties compressed asphalt, made from asphaltic limestone, is so extensively used for roa s, and the like, which satisfy all requirements in regard to resistance to mechanical stresses of all kinds, to frost and heat, etc.

Not every asphaltic limestone can be used directly for making roads, but only such sorts as contain 85-12% bitumen, whose melting point, however, is not higher than 50 C, (regulation of the road authorities). If both requirements are not satisfied, the compressed asphalt will not meet all demands of practice in re ard to durability, softening point, etc. s, now, even in one and the same mine, the amount of bitumen contained in the stone varies very much, it is extremely diflicult to obtain a really good material. i The reason for the great advantages of com ressed asphalt made from the natural pro not was considered to be due to the intimate mechanical mixture of the two components: limestone and bitumen. Various attempts have therefore been made to add bitumen to asphaltic limestone containing too little bitumen. Heat was also used to assist the operation, or bitumen was emloyed in the form of an emulsion. It is l iowever not possible to obtain a ood comhalt by such means. he mass pressed as r as only the properties of cast obtained Specification 0! Letters Patent.

by Dr. H. Koh

Patented Oct. 28, 1919.

Application iilefl August 11, 1915. Serial No. 45,028.

asphalt, because according to the processes mentioned the bitumen was only brought nto mechanical contact with the stone, or, m other words, only surrounds same. Furt-her, all experiments made to mix powdered limestone or chalk with bitumen or other additions (compare Chemical Technology er, page 146) have not resulted in producing a compressible asphalt, but only a product having the properties of cast asphalt, that is, it melts when heated, and it cannot 'be compressed, when it solidifies. This non-success was, in the first place, due to the fact that th chemical process, which unmistakably takes place between the bltumen and limestone in nature, was not recognized. Consequently, an expert came naturally to the conclusion that the artificial production of a stone, which, on being heated, decompose to a loose powder, and can then be compressed, is quite impossible.

Now, according to the present invention, it is rendered possible to produce a compressible asphalt synthetically, which not only in analysis and use shows the properties of natural asphaltic limestone, but even exceeds same by the fact that not only quantity of bitumen, but also the softening point of the bitumen can be chosen within the widest limits, and thus the most advantageous composition for any given purpose can be obtained.

In the endeavor to investigate, and, if ible, to imitate, the o erations which take place in the natural ormation of asphaltic limestone, the inventor first ascertained that the formation of the natural product cannot have taken place in hot condition, because natural asphaltic limestone contains very low boiling hydrocarbons, which are essentially necessary to obtain the desired roperties, and could not be present, if a big er temperature came into question. Further, it was recognized that the formation could not have taken place by bitumen being simply mixed with finely powdered limestone, but that rather a chemical rooess must have taken lace. Considerations of this and other kin s, convinced the inventor that the process in nature must have, been of a chemical character.

Many experiments were made with the object of repeatin this process artificially, till finally the uni orm presence of sulfur in natural asphaltic limestone led to the out 1 T e material used for the purpose consists, 'on the one hand, as in the case of the natural product, of limestone, or any stone containing lime, such as calcareous spar, marble, chalk, etc.

The second material used, as in nature, is some bituminous substance, such as natural asphalt, vegetable and animal oils, mineral. oils, mineral oil residues, tar, tar oil residues and distillates.

If such bituminous substances, by means of sulfonated sebacic acid, or alkaline salts thereof, are converted into an emulsion, this emulsion, in a very dilute condition, will have the pro erty, even at ordinary temperature, to quic 1y react on thewdered limestone, and will form an artificial asphaltlc limestone having all the properties set forth above, the attainment of which forms the object of the present application.

The chemical reaction, which takes place between the sebacic acid and the powdered limestone, causes an intimate union of the limestone and bituminous substances to, be effected.

For the purpose in question sulfo-acids of animal and vegetable oil and fats, or their salts, are very suitable. Sulfonated ricinoleic acids have been found to be of particular advantage. When such are used the reaction is finished in a few minutes, and after mixing the materials the vessel must be quickl emptied, so quickly does the reaction ta e place. The product obtained is at first an extremely lastic kneadable mass which decisively repe water.

pres- The present process is, of course, an invention of the greatest importance. It is not only suitable to entirely replace natural asphalt, but is even supenor to such, inasmuch as this artificial as haltic limestone, as above mentioned, aifor I the possibility of choosing in each case a composltion suitable for the particular conditions and temperature.

What I claim and desire to secure by Letters Patentof the United States is 1. The herein described process of converting limestone into compressible artificial stone which consists in mixing limestone in the presence of a bituminous substance, with a sulfated ricinoleic acid capable of emulsifyinlg such bituminous substance.

2. he herein described process of converting limestone into compressible artificial stone which. consists in mixing powdered limestone with a bituminous substance in the presence of a sulfated non-mineral acid capable of emulsifying the bituminous substance.

3. The herein described process of converting limestone into compressible artificial stone which consists in mlxinglpowdered limestone with a bituminous substance in the presence of a sulfated vegetable acid capa le of emulsifying the bituminous substance.

In testimony whereof, I have signed my nam to this specification in the presence of two subscribing witnesses.

CARL LUDWIG VALENTIN ZIMMER.

Witnesses:

WOLDEMAR HAUPT, HENRY Hasrna.