US1471646A - Agglomerating or cementing granular materials - Google Patents

Description

Patented Get. 23, 123

THOMAS M. CHANCE, OF PHILADELPHIA, PENNSYLVANIA.

AGG-LOMERATING R CEMENTING GRANULAR MATERIALS.

N0 Drawing.

To all whom it may concern:

Be it known that I. THOMAS M. CHANGE, a citizen of the United States, residing at Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented a certain new and useful Improvement in Agglomerating or Cementing Granular Materials, whereof the following is a specifi-- cation.

' My invention relates to the agglomerating or cementing of granular materials such as anthracite or other non-coking coal, coke breeze, ores, concentrates and the like, by the use of a cementing material. It is especially applicable to the manufacture of agglomerated fuel, either in massive form or in the form of briquettes, from anthracite Clllll'l, slack coal, coke breeze and the like and may also be used in the agglomeration or briquetting of ores, concentrates and other granular material.

In agglomerating or cementing materials of this character, where the granular material is inherently stronger than the cementing material, the greatest strength can be obtained in the finished product by close juxtaposition of the particles of granular 7 material and I attain this end by grading artificial the ranular material as to the size of its particles, so that it shall be composed of classes of different size, and so proportioning the weight or volume of each of such classes as to be suflicient approximately to fill the interstices of that of the next larger size, thus decreasing the porosity of the mass as a whole and bringing the individual particles into more intimate juxtaposition.

I have used this invention in the manufacture of briquettes arid massive agglomerated fuel produced by mixin such graded anthracite fines with more nely ground coking coal and subjecting the mixture to sufficiently hi h temperature to coke the coking coal whicl i thus acts as a cement to unite and tie together the individual the granular material.

The strength of many natural and some iroducts may be increased by crushing to re atively small size, that is, small particles may have greater relative strength to resist crushing than large particles. This is doubtless due tothe presence ofnatural cleavage or fracture planes in the larger pieces; for example, the strength of anparticles of tracite coal in cubes of one or two inches in' I size usually ranges from 2000 to 8000 pounds Application filed September 27, 1920. Serial No. 413,196.

per square inch, but I have found by crushing tests that cubes of one quarter inch or one-eighth inch show crushing strength of 10,000 to 18,000 pounds per square inch,in other words, the smaller pieces are relatively stronger than the larger pieces. Hence, one of the improvements which I may employ, and which is necessarily incidental to the grading of the granular material contemplates the crushing of the coarser particles for the purpose of increasing the average strength of the aggregate, at the same time permittin and facilitatin the grading of the partic es as to size as abovedescribed.

Followed to its logical conclusion, this premise would imply that the strongest aggregate would be obtained by crushing all of the granular material to very small size, but this is not practicable if the material is to be agglomerated with a cementing material and if it be desired to obtain as strong a product as possible with a minimum quantity of cementing material, because the re duction of the particles to very small size will prevent successful cementing or agglomeration unless a very large quantity of the cementing material be used, or unless the cementing material be ground or crushed to still smaller size as has been already described.

I do not herein claim the use of such finely divided cementing material to agglomerate relatively coarser granular material except in combination with the invention herein disclosed, as I have made it the subjeet of another application for patent filed simultaneously herewith on September -21, 1920, Serial No. 413,194.

The principles upon which my invention are based may be briefly stated. It is well known that the voids or interstices of any.

granular material in which the particles are of the same shape are practically alike for all sizes, thus, if the particles are of rough angular form and average 1 inch in diameter, the percentage of voids will be about 40 per cent more or less, according to the shape of the particles and how they have been stored, and that material of the same shape and form but of which the particles are much smaller, say 1 16 inch in diameter, will have nearly the same (40) percentage of voids as the coarser material. It is evident that if some such 7 smaller 1/16 inch, material, which is small enough to find lodgement in the interstices between the larger pieces, of

say one (1) inch size, be added to such coarser material, that the voids of such mixed material will be less than the voids of the coarser material, and it is evident that these voids,can be still further reduoed by the addition of still smaller material such for, example as particles 1/80 or 1/100 of an inch. It is possible in this Way to greatly reduce the total voids of any granular material and thus to increase the strength of the material by increasing the number of the points of contact of particle with particle, and at the same time to gain an increase in the strength from the greater relative strength of the smaller particles as compared with that of the larger particles as already described.

it will occasionally be found that the relative proportions as to sizes of coarse and finer materials is such as to conform more or less closely to the conditionsrequisite for maximum strength without grading as herein described, but generally grading will be found advantageous and,often will be essential to insure uniformity in the percentage of voids and in the strengthof the material that is to be agglomerated.

l have found that the above relation will exist if a quantity of granular material of approximately inch to 20 mesh is mixed with one and a half times that quantity of granular material from 20 to 120 mesh. Ob-

viously this proportion may vary with the size of materials and for the purpose desired, but this particular relation has been found satisfactory for many purposes.

Having described my invention I claim:

1. A process of agglomerating non-coking material which includes the steps of mixing two grades of non-coking material with a coking bituminous binder in the proportion of not more than 25% of coarse noncoking material, not less than 50% of fine non-coking material, and the remainder coking bituminous binder.

2. The process of claim 1. the particles of coking bituminous binder being relatively much smaller than the other particles.

3. The process of claim 1, the size of the various grades being as follows: coarse non coking material inch to 20 mesh, fine noncoking material 20 mesh to 120 mesh, binder, smaller than 120 mesh.

In testimony whereof I have hereunto signed my name at Philadelphia, Pennsylvania, this 24th day of September 1920.

THOMAS M. crimson.

Witnesses:

J. H. QUINN, CARL K. SGHULZE.