US2620267A - Method of making a slag-forming agent - Google Patents

Description

Patented Dec. 2, 1952 OFFICE METHOD OF MAKING A SLAG-FORMING AGENT Frederick E. Kern, St. Louis, M0.

N Drawing. Application January 21, 1949, Serial No. 72,087

This invention relates in general to certain new and useful improvements in slag-forming agents and methods of making the same.

In various metallurgical procedures such as the refining of iron into steel by the use of basic slag-forming material, or the pouring of gray iron and semi-steel castings by the use of basic fluxes in the pouring ladles, or the refining oi non-ferrous metals by heat treatment processes involving the use of basic slags, it is conventional practice to add to the so-called heat or the ladle, as the case may be, various types of slag forming agents such as fluorite, fluorspar, cryolite, apatite, wollastanite, lime and similar materials. These slag-forming agents combine with the various impurities in the molten metal to form chemical compounds which are insoluble in the molten metal and hence float to the surface in the formation of a slag. Because the slags thus formed frequently have melting points which are somewhat higher than the melting point of the metal being refined, it is necessary to include among the slag-forming agents added during the metallurgical process, materials which will reduce the viscosity of the slag or, in other words, render the slag more fluid. Various fluorine-containing materials such as fluorite, fluorspar, and cryolite are well recognized as slag fluidizing agents and are conventionally used for this purpose.

It so happens that there are relatively few economically usable deposits of metallurgical fluorspar or fluorite available in the United States and the mining of these deposits is a somewhat expensive procedure. Furthermore, in the mining of these fluorspar and fluorite deposits, a relatively large tonnage of fines is produced. It is virtually impossible, however, to introduce the fines into a furnace because the high temperatures and draft blow the fine materials away from the molten bath and prevent the fines from becoming properly incorporated in the metallurgical mixture. Thus the fines resulting from the mining of fluorite, have up to the present time, been considered as a waste material.

It is, hence, the primary object of the present invention to provide a slag-forming agent or flux for use in metallurgical processes, which utilizes as one of its principal ingredients the fines resulting from the mining of fiuorspar, fluorite, cryolite, and similar minerals.

A further object of the present invention is to form a plastic substance from fluorites and related materials which is capable of being molded or molded and briquetted under pressure or by 1 Claim. (Cl. 75-3) extrusion in the form of bricks, blocks, and other specific shapes of any desired size or dimension.

Another object of this invention is to form a combination between suitable non-organic gelatinous substances and the fluorine-containing materials to form an agglomerated mass which may be molded, briquetted or extruded and will thereupon set rapidly into a hard abrasion-resistant regular shape in which form the material is easy to handle, and can be introduced into the cupola furnaces without disintegrating into a powdery substance.

Another object of this invention is to form abindin adhesive material for the fines which is easily prepared from water soluble chemical reagents and which will rapidly disseminate throughout the fluorite fines thereby shortening the process of mixing.

Another important object is to form a slagforming metallurgical agent in solid masses of regular shape which may be stored in the open without danger of disintegration.

Another object of the present invention is to provide a slag-thinning metallurgical agent which is of uniform size, shape, constituency, and physical consolidation or condensity so that when such agent is added to the slag the addition thereof may be precisely controlled and conveniently carried out.

Another object of the present invention is to provide slag-forming agents in briquette form by the use of combinations of binders which in themselves do not contain any substantial or significant quantities of materials which would be deleterious to the metallurgical process.

' An additional object of the present invention is to provide methods for making briquettes of the type stated which methods are simple and economical.

With the above and other objects in view, my invention resides in the novel processes and compositions of matter presently described and pointed out in the claim.

Broadly speaking, my invention resides in the conversion of finely divided, comminuated,v or powdered fluorine containing minerals such as flucrspar, fluorite, and the like to a quick setting agglomerate containing minimum quantities of lime and siliceous compounds and thereupon briquetting or otherwise molding the agglomerate into solid particles of some suitable predetermined shape and size. More particularly a dry mixture of fluorite mineral fines (preferably not coarser than 10 mesh), Portland cement, and lime is prepared and placed in a suitable muller,

pug mill, or similar masticating equipment. A measured quantity of water glass or similar alkaline earth silicate is placed in a mechanical mixer or in a suitable vat and a predetermined quantity of aqueous solution of ferric chloride of desired concentration is added thereto under such conditions as will produce a precipitation of colloidal hydrous oxide of silica or silica gel as it is sometimes called, and colloidal hydrous oxide of iron or iron ge as it is sometimes called. This mixture of iron and silica gels is thereupon stirred to produce a homogenous colloidal mass having the consistency of a rather granular heavy jelly or paste suspended in a supernatant liquid. This dispersion is then immediately introduced into the muller, pug mill, or other similar masticating equipment into which the dry mixture of fluorites, lime and cement has already been placed and the entire mixture subjected to masticating or homogenizing action so as to thoroughly incorporate the dry ingredients into the colloidal dispersion. This masticating or homogenizing process is continued for a sufficient time to permit complete intermixture or agglomeration of the ingredients. The quantitative relationship between the amount of dry materials and liquids compounded in the above manner is such that the material, at the completion of the mastication step, will take on the lumpy, non-fluid appearance. of a dampened but not completely wetted powder.

This mixture is briquetted in a suitable briquetting press under pressures of approximately 4,000 pounds per square inch. The briquettes thus formed are relatively dry, structurally strong, and, upon being allowed to set under normal atmospheric conditions for a relatively short period, such as an hour or two, will solidify into a thoroughly indurated mass.

By way of illustration and not by way of limitration the following are preferred examples of the present invention.

EXANEPLE I (a) Dry mix Pounds Fluorsparfines 1600 Lime (hydrated) 160 Portland cement 240 (b) Gel Dilute 80 lbs. of water glass (42 B.) by addition thereto of 40 lbs. H2O.

Dissolve 30 lbs. of ferric chloride in 40 lbs. water.

Add ferric chloride solution slowly with stirring to diluted water glass. Continue to stir until dispersion is homogeneous.

(c) M astz'cation Add gel to dry mix gradually while constantly mulling and continue mulling until mixture is uniformly agglomerated.

(d) Briquetting Compress masticated mixture in briquetting' press under pressure of approximately 4,000 lbs. per square inch and allow the briquettes to harden under atmospheric conditions.

EXAMPLE II (a) Dry mix Pounds Cryolite fines 1600 Lime (hydrated) 160 Portland cement 240 4 (22) Gel Dilute lbs. of water glass (42 B.) by addition thereto of 40 lbs. H2O.

Dissolve 30 lbs. of ferric chloride in 40 lbs. water.

Add ferric chloride solution slowly with stirrin to diluted water glass. Continue to stir until dispersion is homogeneous.

per square inch and allow the briquettes to harden under atmospheric conditions.

EXAMPLE III (a) Dry mix Pounds Fluorspar fines 1600 Lime (hydrated) Portland cement 240 (1)) Gel Dilute 80 lbs. of water glass (42 Be'.) by addition thereto of 40 lbs. H2O.

Dissolve 30 lbs. of magnesium chloride in 40 lbs. water.

Add magnesium chloride solution slowly with stirring to diluted Water glass. Continue to stir until dispersion is homogeneous.

(c) M astication Add gel to dry mix gradually while constantly mulling and continue mulling until mixture is uniformly agglomerated.

(d) Briquettivzg Compress masticated mixture in briquetting press under pressure of approximately 4,000 lbs. per square inch and allow the briquettes to harden under atmospheric conditions.

EXAMPLE IV (a) Dry mix Pounds Fluorspar fines 1600 Lime (hydrated) 160 Portland cement 240 (17) Gel Dilute 80 lbs. of water glass (42 B.) by addition thereto of 40 lbs. H2O.

Dissolve 15 lbs. of manganese chloride in 40 lbs. of water.

Add manganese chloride solution slowly with stirring to diluted water glass. Continue to stir until dispersion is homogeneous.

(c) M astication Add gel to dry mix gradually whileconstantly mulling and continue mulling until mixture is uniformly agglomerated.

(d) Briquetting Compress masticated mixture in briquetting press under pressure of approximately 4,000 lbs. per square inch and allow the briquettes to harden under atmospheric conditions.

EXAMPLE V (a) Dry misc Pounds Fluorspar fines 1600 Lime (hydrated) 160 Portland cement 240 (b) Gel Dilute 100 lbs. of water glass (42 Be.) by addition thereto of 50 lbs. of water.

Add 40 lbs. of hydrochloric acid Be.) slowly with stirring to diluted water glass. Continue to stir until dispersion is homogeneous.

(c) M astication Add gel to dry mix gradually while constantly mulling and continue mulling until mixture is uniformly agglomerated.

(d) Brzquetting Compress masticated mixture in briquetting press under pressure of approximately 4,000 lbs. per square inch and allow the briquettes to harden under atmospheric conditions.

It should be understood, of course, that the above examples are merely representative of the present invention. It has been found, for example, that fluorspar briquettes can be made by mixing fluorspar fines, lime, Portland cement and water glass in an initial mixture in a muller or in a pug mill and thereupon adding the gel precipitant such as an aqueous solution of a polyvalent metal chloride, hydrochloric acid, acetic acid or the like. Similarly, it is possible to add the gel precipitant solution directly to the dry mixture in the muller and thereafter add the water glass. The mixtures thus formed may also be briquetted and the briquettes allowed to harden, thereby producing a slag-forming metallurgical reagent which can be readily added in precisely controlled quantities as desired to molten metallurgical mixtures to act as a flux material in the slag.

It should be understood that changes in the methods, compositions, percentages, and combinations above set forth may be made without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

6 The method of making a metallurgical slagforming agent which comprises preparing a dry mixture having approximately the following constituency:

Parts by weight Fluorspar fines 16 Lime (hydrated) 1.6 Portland cement 2.4

forming a gel type binder by diluting approximately 8 parts by weight of water glass with approximately 4 parts by weight of water, slowly adding thereto a solution consisting of approximately 3 parts by weight of ferric chloride and 4 parts by Weight of water, stirring the resulting precipitate to form a finely divided aqueous dispersion of the silica gel and iron gel, adding the gel to the dry mixture with continuous mulling until the mixture is thoroughly agglomerated, and compressing the agglomerated mixture into briquettes.

FREDERICK E. KERN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 128,365 Crawford June 25, 1872 464,815 Conkling Dec. 8, 1891 958,700 Glass May 17, 1910 1,038,370 Hubner Sept. 10, 1912 1,536,033 Stillman Apr. 28, 1925 1,549,314 Conlin Aug. 11, 1925 1,739,839 Jung Dec. 17, 1929 1,741,544 Slagel Dec. 31, 1929 1,920,246 Dandt Aug. 1, 1933 1,982,541 Scripture Nov. 27, 1934 2,184,078 Hyde Dec. 19, 1939 2,220,385 Abbott Nov. 5, 1940 2,459,203 Vahrenlzamp Jan. 18, 1949 FOREIGN PATENTS Number Country Date 23 Great Britain 1866 134,598 Great Britain Nov. 3, 1919 OTHER REFERENCES "Concise Chemical and Technical Dictionary, published by Chemical Publishing Co., 1947, page 835.