US2514901A - Bituminous emulsions for treatment of coal and methods of preparing same - Google Patents

Description

Patented July 1 1, 1 950 I BITUMINOUS EMULSIONS FoR TREATMENT oEcoAL AND METHODS OF PREPARING I SAME Charles R. Rosencranse, Pittsburg, Kans., assignor of fifty per cent to Joe F. Klaner, J1'., Pittsburg,

a Kans.

i i No. Drawing.

This invention relates to. a colloidal suspension to be sprayed on coal to form a permanent coating rendering the coal substantially dust-proof and impervious to moisture and oxidation, the present subject matter involving an improvement over the subject matter in my Patent No- 2,431,89L'issued December 2, 1947.

An imp'ortantobject'of this invention is to provide a colloidalsuspension which does not require the application of heat when it is sprayed or coated on coal, andwhich while forming a hard, dry, and permanent coating on the coal, does not cause the coalparticles to objectionably adher togethen;

Another important object of the invention is I to provide a bituminous emulsion for coating coal may come into contact.

By coal as referred to herein, is meant bituminous, semi-bituminous, anthracite, semiobjects or materials; with which the coated coal anthracite, or the so-called lignite. coals, and

others comprehended by these terms.

After extensive experimentation with the process and composition disclosed in the patent mentioned' hereinabove, I have discovered that a number of improvements could be made wherein the'resulting emulsion produces a better sheen and color on the. coal treated, affords better protection to the coal, and produces an odorless coating for the coal.

The primary improvement resides in the substitution of coal tar pitch for the asphalt,.arti'- ficial or natural, employed in the patented process. As is well known in the art, coal tar pitch is the residue from the distillation of coal tar from which the aromatic substances have been removed." Coal tar pitch is a solid substance of varying'degrees of hardness whichis determined by the amount of distillation used to remove the aromatic substances. In the dry state it has an approximate specific gravity of 1.20. ,7

Since coal tar pitfchisless soluble than asphalt, obviously coal coated withcoal tar pitch willbe better protected against moisture and oxidation. ".elsogcoal coated with coal tar pitch is relatively Application November 17, 1948, Serial No. 60,634

j v a I SClainisJ, (c1. iota-277) odorless as compared to coal coated with asphalt emulsion. To the best of the applicant's knowledge, coal tar pitch has never before been successfully employedin manufacturing an emulsion for the treatment of coal because of the acidity of the pitch. The herein described improved process and composition includes a novel method of reducing this objectionable acidity.

In the patented process before the asphalt is run through the colloid mill for admixture with the aqueous dispersion, it was found necessary to use an asphalt having an initial penetration of 8 to 10 mm. and preferably a ductility rating of about 15 to 18 mm. and then blowing the asphalt at an oxidizing temperature inan oxidizing chamber with about 4,000 cubic'feet of air per minute for a length of time necessary to reduce the penetration of the asphalt to about 2.6 to 3.0 mm.

thereby raising the melting'point' of the asphalt to about 210 to 260 degrees F. While the same treatment can be applied to coal tar pitch with advantageous results, it has been found herein that no such treatment is required when a coal F. is employed.

In the patented, process it was also necessary to simultaneously run the heated and treated asphalt together with the heated aqueous dispersion through a colloid mill operating at substantially 5,000 B. P. M. and at a constant rate. A marked advantage is obtainedby running the colloid millat approximately half its normal rate of speed.

It has been found that by reducing the amount of material entering the colloid mill instead of reducing the speed of thev mill itself, a marked improvement of the resulting emulsion is obtained with respect to the stability of the emulsion. In other words, rather than reduce the speed of the colloid mill by one' half, the material is fed into the mill at a rate equal approximately to onehalf of the flow or output capacity of the mill. .In the patented process, also, an aqueous dispersion was employed containing a number of essential ingredients.

The applicant has found that a variation ofthe percentages by weight of these ingredients produces a dispersion which allows the substitution'of'coal tar pitch for asphalt and which also permits him to dispense with the blowing' orpre-treatment of both the asphalt and the coal tar pitch.

f Moreover, theapplicant has found that a prior mixture. in a ;mixing chamber of the heated asphalt and coal tar-pitch with the aqueous disthe preferred embodimentbeing coalutarwpitch.

When employing asphalt, a material having a penetration of 2.6 mm. ispreferred and if an asphalt having a higher penetration is employed it will be found advantageous to reduce the penetration and raise the melting point thereof by the oxidation and blowing treatment fully de If a coal tar scribed in the patented process. pitch having a penetration of from 26to 30 .mm. and a melting point of from 190 to 210 degrees F. is employed, no pre-treatmentsuch asblowing or oxidation is required The coal tar pitch is then heatedin a container until it is fluid, that is, to atemperature not exceeding 300 degrees F., and then runpreferably into a mixing chamber where it is mixed with preferably an equalvolume of anaqueous dispersion to be described hereinafter. Thereafter the admixture or suspension of the pitchand the dispersion is runinto .a colloid mill at a velocity equal approximately to one-half of .the flow capacity of the colloid mill. That is, if the capacity of the colloid .milll'is 4,000 gallons per hour, the speedof the pumps whichintroduoe the suspension intothe mill i'slreduced so that the mill can only produce 2,000 gallons .per hour.

The liquid phase of the emuls'ionor what may be termed the aqueous dispersion-comprises the following ingredients:

Water 93.74-95.04 Resin 3.00 Bentonite clay 1.40 1.60 Tall oil s 0.10

Caustic soda Per cent by Weight Water 93.74 Resin 3.00 'Bentonite clay 1.60 Tall oil 0.10 Caustic soda 1.56

It will be noted that the dispersion-mentioned immediately hereinabove differs from the onedisclosed in the Patent 2,431,89lin that the amount of bentonite clay and caustic soda is increased. The increased bentonite content improves the stability of the emulsion and the increased amount of caustic soda neutralizes the acidity inthe coal tar pitch, which acidity was responsible for the prior inabilityofproviding a stable Per cent by weight r emulsion from bituminouslmaterial such as coal tar pitch.

It has also been found that a prior treatment of the coal tar pitch when heated to a state of fluidity before admixture with the aqueous. dispersion improves the stability of the emulsion and the coating properties thereof. This prior treatment includes the addition of a weak solution of caustic soda in glycerine to the fluid coal tar pitch. The preferred amount of caustic soda to be added to the coal tar pitch is 0.44% by "weight 'of' the-caustic soda to the weight of the coal tar pitch. This solution of caustic soda and glyoerine is, of course, thoroughly mixed throughout the fluid coal tar pitch phase.

Thus it will be seen that a novel process and composition is provided for coating coal whereby the latter will be rendered impervious to moisture; oxidation, etc. The coating material of the present invention, requiring no heating above its freezing point, can be sprayed or atomized on the coal, directly from the storage containers, and

by -means of any suitablesprayin'g equipment. The bituminous emulsion provided by the improved-process hereinabove described produces a betterv sheen and'color on the coal, affords better protection to thecoalilbecause of the lesser solubility of coaltarpitchas compared to asphalt, andproduces a relativelyodorless coating for the coal.

While a preferred embodiment of the applicanrs process and composition has been described hereinafter, itwill bereadily understood that minor variations in 'the process and composition may be made by those skilledfin the art without departing from the spirit .of the -inventionand the scope of the appended-claims.

Having described the invention, what is claimed asnew is:

1. The method of vmaking a collo'idal suspension for spraying on coal'at atmospheric temperature to form a permanent coating rendering the coal substantially dust-proof and-impervious to moisture and oxidation, comprising heating coal tar pitch having apenetration of 2.6-. to 30.0 mm. and amelting point-05190 to 260 F. to a temperature not over 300 F., running the heated coal 1 tar.pitch through a mixing chamber together with an aqueous -dispersion heated to about 180 .thenisimultaneously running the suspension through a colloid mill at a velocity equal approximately to one-half of the'fiow capacity of themill, said dispersion comprising by weight substantially 93.7.4-95.04% .water, 3.00% of a substantially'petroleumlhydrocarbon insoluble pine. wood resin, l 40-1.60% bentonite, 0.10% tall oil, and DAG-1.56% caustic soda,- then rapidly reducing the resultant emulsion-to a tem perature of 150-F, for storage.

'2. The process-of claim 1, and the step of adding to the heated coal tar pitch prior .to admixture with the dispersion a relativelyweak solution of caustic soda Zin-glycerine.

v3. The processof claim 2, wherein the caustic soda is. added in an-amount equal lie-0.44% by Weight of the coal tar pitch.

4. The method of making .a colloidal-suspension .for spraying on coal at atmospheric temperature to form a permanent coating rendering the coal substantially dust-proof and impervious to moisture and oxidation, comprising heating to a temperature not over 300- F.', coal tarpitch having a penetration of 26-30' mm. and a melting point of 190-2l0 F.,,running the, heated vpitch through a mixing. chamber together with an simultaneously running the sus ension through a ture with the dispersion a relatively weak solution of caustic soda in glycerine.

6. The process of claim 5, wherein the caustic soda is added in an amount equal to 0.44% by weight of the coal tar pitch.

7. The method of making a colloidal suspension for spraying on coal at atmospheric tem-- perature to form a permanent coating rendering the coal substantially dust-proof and impervious to moisture and oxidation, comprising heating to a temperature not over 300 F., coal tar pitch having a penetration of 26-30 mm. and a melting point of 190-210 F., simultaneously running the heated pitch through a colloid mill together with an aqueous dispersion heated to ,about 180 F., said dispersion containing by weight substantially 95.04% of water, 3% of a substantially petroleum hydrocarbon insoluble pine wood resin, 1.4% of bentonite, 0.10% of tall oil, and

' 0.46% of caustic soda, then rapidly reducing the temperature of the resultant emulsion-to about F., for storage. 8. A colloidal suspension for spraying on coal at atmospheric temperature to form a permanent coating rendering the coal substantially dust-proof and impervious to moisture and ox-i dation, comprising coal tar pitch having a pene tration of 26-30 mm. and a melting point of 190-210 F, which has been simultaneously run through a colloid mill together with anaqueous dispersion heated to about F.- at a velocity equal approximatelyto one-half oi the flow ca pacity of the mill, said dispersion comprising by weight substantially 93.74% water, 300% of a substantially petroleum hydrocarbon insoluble pine wood resin, 1.60% bentonite, 0.10% tall oil, and 1.56% caustic soda.

CHARLES R. ROSENCRANSE.

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

UNITED STATES PATENTS Number Name Date 1,807,808 Symons June 2, 1931 2,190,034 Levin Feb. 13, 1940 2,431,891 Rosencranse Dec. 2, 1947 FOREIGN PATENTS Number Country Date 462,111 Great Britain Mar. 2, 1937

Claims (1)

1. THE METHOD OF MAKING A COLLOIDAL SUSPENSION FOR SPRAYING ON COAL AT ATMOSPHERIC TEMPERATURE TO FORM A PERMANENT COATING RENDERING THE COAL SUBSTANTIALLY DUST-PROOF AND IMPERVOUS TO MOISTURE AND OXIDATION, COMPRISING HEATING COAL TAR PITCH HAVING A PENETRATION OF 2.6 TO 30.0 MM. AND MELTING POINT OF 190* TO 260*F. TO A TEMPERATURE NOT OVER 300*F., RUNNING THE HEATED COAL TAR PITCH THROUGH A MIXING CHAMBER TOGETHER WITH AN AQUEOUS DISPERSION HEATED TO ABOUT 180*F., THEN SIMULTANEOUSLY RUNNING THE SUSPENSION THROUGH A COLLOID MILL AT A VELOCITY EQUAL APPROXIMATELY TO ONE-HALF OF THE FLOW CAPACITY OF THE MILL, SAID DISPERSION COMPRISING BY WEIGHT SUBSTANTIALLY 93.74-95.04% WATER, 3.00% OF A SUBSTANTIALLY PETROLEUM HYDROCARBON INSOLUBLE PINE WOOD RESIN, 1.40-1.60% BENTONITE, 0.10% TALL OIL, AND 0.46-1.56% CAUSTIC SODA, THEN RAPIDLY REDUCING THE RESULTANT EMULSION TO A TEMPERATURE OF 150*F. FOR STORAGE.