STATE OF ILLINOIS WILLIAM G. STRATTON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION VERA M. BINKS, Director DIVISION OF THE STATE GEOLOGICAL SURVEY M. M. LEIGHTON, Chief URBANA CIRCULAR NO. 190 PLASTIC AND SWELLING PROPERTIES OF ILLINOIS COALS BY O. W. REES and E. D. PIERRON PRINTED BY AUTHORITY OF THE STATE OF ILLINOIS URBANA, ILLINOIS 19 54 ILLINOIS GEOLOGICAL SURVEY LIBRARY ORGANIZATION STATE OF ILLINOIS HON. WILLIAM G. STRATTON, Governor DEPARTMENT OF REGISTRATION AND EDUCATION HON. VERA M. BINKS. Director BOARD OF NATURAL RESOURCES AND CONSERVATION HON. VERA M. BINKS, Chairman W. H. NEWHOUSE, Ph.D., Geology ROGER ADAMS, Ph.D., D.Sc, Chemistry R. H. ANDERSON, B.S., Engineering A. E. EMERSON, Ph.D., Biology LEWIS H. TIFFANY, Ph.D., Pd.D., Forestry W. L. EVERITT, E.E., Ph.D., Representing the President of the University of Illinois DELYTE W. MORRIS, Ph.D., President of Southern Illinois University GEOLOGICAL SURVEY DIVISION M. M. LEIGHTON, Ph.D., Chief (89157—1500—3-54) jC PLASTIC AND SWELLING PROPERTIES OF ILLINOIS COALS BY O. W. REES AND E. D. PIERRON Introduction For several years the plastic and swelling properties of Illinois coals have been studied in connection with research projects at the Illinois Geological Survey. Data have ac- cumulated as a part of a fund of informa- tion on the characteristics of the reserves of coal of various ranks in Illinois, particularly from studies of the use of coal in underfeed stokers and the making of metallurgical coke. Similar properties of other coals, es- pecially Eastern coals used in experimental blends for producing metallurgical coke> have been studied also. This report will summarize, classify, and compare the results accumulated from the various investigations. Historical Of the numerous types of equipment for measuring plastic properties of coal, three types have been tried in this laboratory : Agde-Damm, Davis, and Gieseler plasto- meters. The Agde-Damm apparatus gives reproductible results, but the data are not readily interpreted in terms of practical ap- plication. Illinois coals, in general, are of low plasticity, and the Davis plastometer has not been found to give good results with these coals. In our experience the Gieseler plastometer has given the most useful re- sults, and consequently, the plasticity data discussed in this report were obtained by means of this equipment. Apparatus Our Gieseler plastometer was built in the Survey machine shop with minor changes from the description published by Soth and' Russell. 1 The Survey instrument includes G. C, and Russell, C. C. Testing Mats., vol. 43, p. 1176. Proceedings, Am. Soc. 1943. a modification in the plastometer head (see fig. 1 ) to permit a fixed position of the thrust bearings and provision for removal of decomposition gases by suction with a water aspiration pump. The device for packing the sample in the plastometer (see fig. 2) was a modification of that described by Soth and Russell. We added more guides to insure proper packing and assembly of the plastometer, as this, step in the determination is of primary im- portance. A manually operated auto-transformer controls the temperature of the heating bath to give a steady rate of heat rise (3°C. per minute). Temperature readings are ob- tained by means of a chromel-alumel thermo- couple in the heating bath immediately ad- jacent to the sample cup of the plastometer, which is connected to a Bristol pyrometer calibrated from 250°C. to 550°C. for direct reading. The dial of the instrument is mounted with a ball bearing, and the pointer is counterbalanced. The frictional load of the plastometer has been found to be 0.9 grams at room temperature and at 400° C. This is determined by observing the minimum weight that will start and maintain move- ment of the dial under test conditions but without a sample. Frequent calibrations are made* after thoroughly cleaning and lubri- cating the bearings. The stirring shafts are replaced after approximately 100 determina- tions. Free-swelling index determinations are made according to a modification of the standard British Swelling Index test, which was adopted in 1946 by the American So- cietv for Testing Materials as its Standard Method of Test for Free-Swelling Index [3] 4 PLASTIC AND SHELLING PROPERTIES OF ILLINOIS COALS INSIDE BEARINGS 32 ^_ 9 "__ ^~ t " 28 TAP Fig. 1. — Gieseler plastometer shaft. of Coal, D720-46. 2 In this laboratory it was necessary to use a blast type gas burner with flow meters in both the air and gas feed lines to obtain the proper rate of heat- ing and final temperature. Samples For the most part the coal samples studied in this report were commercial products of mines rather than mine face samples. They include sized coals used in the carbonization research program and prepared stoker coals used in the stoker research studies. Some of the coals were washed and others were un- washed. Laboratory samples were prepared from gross samples by standard methods. For the Gieseler plasticity tests the laboratory samples were air dried and pulverized to minus 40 mesh with a minimum of finer sizes. For the free-swelling index test, samples were air dried and pulverized to minus 60 mesh. 2Test for Free-Swelling Index of Coal, D720-46: ASTM Standards on Coal and Coke, p. 70, Sept. 1951. DUPLICABILITY OF RESULTS In order to expedite the study it has been necessary in most instances to make only single determinations of plastic character- istics with the Gieseler plastometer. How- ever, some determinations have been made in duplicate (two or more determinations on identical samples made within a 24-hour period), which provide data, although meager, for a study of duplicability. Table 1 compares 35 duplicates (18 for fusion temperature) for individual coals. Average differences between duplicates for deter- mined significant temperatures are of the order of 1.0% with ranges from a low of zero to high of 5.6% for softening temper- ature and zero to 2.5% for setting temper- atures. Such duplicability seems to be rea- sonably satisfactory. However, duplicability of maximum fluidity values is not nearly so satisfactory. The average difference is 20% ; the range is wide — zero to 87.5%. Table 1. — Duplicability of Gieseler Plastometer Results Number of pairs. . Average diff., %. . Minimum diff., %. Maximum diff., % Softening temperature 35 1.3 0.0 5.6 Fusion temperature 18 0.8 0.0 2.7 Max. fluidity temperature 35 1.0 0.0 3.4 Setting temperature 35 0.7 0.0 2.5 Max. fluidity (dial div. per min.) 35 20.0 0.0 87.5 DVPLICABILITY OF RESULTS ■HHaiMHHHanHnfUHnBBnHUHnBnnBnBnHUHMHHnraBHi Fig. 2. — Packing device for Gieseler plastometer. PLASTIC AND SWELLING PROPERTIES OE ILLINOIS COALS Discussion The various values determined with the Gieseler plastometer are defined as follows: Softening Temperature. — The tempera- ture at which dial pointer movement reaches 0.5 dial divisions per minute. Eusion Temperature. — The temperature at which dial pointer movement reaches 5.0 dial divisions per minute. Maximum Eluid Temperature. — The temperature at which the dial pointer move- ment reaches maximum rate. Setting Temperature. — The temperature at which dial pointer movement stops. Maximum Fluidity. — The maximum rate of dial pointer movement in dial divisions per minute. Plastic Range. — The temperature range, from the Softening Temperature to the Set- ting Temperature, in which the coal is plastic. Maximum fluidity values are reported to the nearest unit where ten or greater. Free- swelling index values are reported to the nearest 0.5 unit. Table 2 gives average Gieseler plasticity and free-swelling index results for Illinois coals arranged according to county, rank, and seam. Table 3 and figure 3 present average values for the various plasticity and swelling characteristics of U. S. coals ar- ranged according to rank of coal from the low-volatile bituminous coals through the high volatile bituminous C coals. The data shown in table 2 cover three ranks of coal found in Illinois: high-vola- tile bituminous A, B, and C. As far as possible, tabulated values are averages of two or more determinations made on dif- ferent samples of coal within the same group. High and low values are included to show the wide differences, particularly in maximum fluidity, for coals within a given group. The fact that both maximum fluidity and free-swelling index values are definitely influenced by oxidation of the coal samples may contribute, at least in part, to these differences. It seems wise to place more confidence in averages for sev- eral coals than in individual determinations. Furthermore, such data should be consid- ered more qualitatively than quantitatively in making comparisons. Referring again to table 2, it will be seen that the high-volatile bituminous A coals of the No. 5 seam in Gallatin County show the highest maximum fluidity of the Illinois coals for which data are available. The high-volatile bituminous B coals of the No. 5 seam show the next highest maximum fluidity, whereas coals of this same rank in the No. 6 seam show the low- est maximum fluidity of any group of Illi- nois coals. Considering all high-volatile bituminous C coals together regardless of county or seam, it will be seen that, on an average, they appear to be somewhat more fluid than those of the next higher rank. Free-swelling index values, decrease with decreasing rank except for the high-volatile bituminous A coal, whose average is shown as one unit lower than that for the next lower rank. However, only two values for high-volatile bituminous A coal were avail- able for averaging, one of which was the highest shown in table 2. For ready comparison of plastic and swelling characteristics of Illinois coals with higher-rank Eastern coals, average values for the ranks from low-volatile bituminous through high-volatile bituminous C are tab- ulated in table 3 and shown graphically in figure 3. Maximum fluidities of Illinois coals are shown to be lower than those of Eastern high-volatile bituminous coals. In addition, significant temperature values for the Illinois coals are lower. Free-swelling index values decrease with decrease of rank throughout the range of ranks shown. GIESELER PLASTICITY AND FSI VALUES Table 2. — County Average Gieseler Plasticity and Free-Swelling Index Values for Illinois Coals County Soft temp. °C. Fusion temp. °C. Max. fluid, temp. °C. Setting temp. °C. Max. fluid, div./min. Free- ;welling index lallatin Average No. Averaged. High Low 375 3 377 373 No. 5 Seam Coals (Rank HVAB) 399 3 401 396 428 3 435 424 474 3 487 461 3098 3 4500 1579 5.0 2 6.5 3.5 No. 5 Seam Coals (Rank HVBB) Jackson Average No. Averaged. High Low Saline Average No. Averaged. High Low Williamson Average No. Averaged. High Low 366 2 368 364 388 16 416 357 389 10 404 363 404 2 404 404 415 16 442 392 413 10 431 390 433 2 434 432 433 16 457 417 432 10 443 414 466 2 468 463 463 16 485 449 464 10 474 456 192 2 238 146 49 16 150 14 86 10 345 12 6.0 2 6.0 5.5 5.0 11 5.5 4.0 4.0 2 4.0 4.0 No. 6 Seam Coals (Rank HVBB) Douglas Average No. Averaged. High Low Franklin Average No. Averaged. High ... Low Jefferson Average No. Averaged. High Low Perry Average No. Averaged. High Low Williamson Average No. Averaged. High Low 362 1 386 40 413 355 391 3 393 390 379 5 391 369 393 9 406 386 414 1 417 15 430 406 424 3 425 422 417 4 431 407 418 6 420 417 429 1 423 40 441 404 430 3 431 428 426 5 432 420 433 9 440 425 460 1 454 40 468 442 457 3 457 457 456 5 465 445 461 9 466 452 6.4 40 42 1.8 7.0 3 7.3 6.8 3.1 13 9 34.0 2.4 4.0 1 4.5 64 6.0 2.5 5.5 1 4.0 6 5.0 2.5 5.0 8 6.0 4.0 8 PLASTIC AND SIVELLING PROPERTIES OF ILLINOIS COALS Table 2 — Continued Count v Soft temp. °C. Fusion temp. °C. Max. fluid, temp. °C. Setting temp. °C. No. 1 Seam Coals (Rank HVCB) Henry Average No. Averaged High Low Knox Average No. Averaged High Low Grundy Average No. Averaged High Low Hancock Average No. Averaged High Low La Salle Average No. Averaged High Low Will Average No. Averaged High Low Peoria Average No. Averaged High Low Sangamon Average No. Averaged High Low Woodford Average No. Averaged High Low No. 2 Seam Coals (Rank HVCB) 374 1 326 2 340 312 373 9 392 338 432 1 401 1 416 5 421 408 432 1 417 2 418 416 425 9 437 399 456 1 446 2 449 442 455 9 464 441 No. 5 Seam Coals (Rank HVCB) Max. fluid, div./min. 19 2 34 4.6 13 9 49 1.2 GIESELER PLASTICITY AND FSI VALUES Table 2 — Concluded County Soft temp. °C. Fusion temp. °C. Max. fluid, temp. °C. Setting temp. °C. Max. fluid, div./min. Free- swelling index No. 6 Seam Coals (Rank HVCB) Macoupin Average No. Averaged High Low Madison Average No. Averaged High Low Perry Average No. Averaged High Low Randolph Average No. Averaged High Low St. Clair Average No. Averaged High Low Vermilion Average No. Averaged High Low Washington Average No. Averaged High Low Will Average No. Averaged High Low 345 2 349 341 385 2 388 381 374 1 392 1 417 1 408 2 409 407 423 2 425 420 408 1 439 2 439 438 439 2 445 432 442 1 No. 7 Seam Coals (Rank HVCB) 333 1 401 1 425 1 465 1 20 2 36 4.9 2.1 1 158 1 4.0 4 4.5 3.0 3.0 3 3.5 3.0 4.5 9 5.0 3.5 4.0 2 4.0 3.5 4.0 3 4.5 3.5 4.0 6 4.0 3.5 4.5 1 2.5 1 10 PLASTIC AND SHELLING PROPERTIES OF ILLINOIS COALS Table 3. — Gieseler and Free-Swelling Index Data for United States Coals. Rank Average Values Rank Low- 1 ol. Bituminous Average No. Averaged High r Low Medium-Vol. Bituminous Average No. Averaged High Low High- Vol. A Bit. {Eastern) Average No. Averaged . High Low High- Vol. A Bituminous Illinois No. 5 Seam Average No. Averaged High Low High- Vol. B Bituminous Illinois No. 5 Seam Average No. Averaged High Low High- Vol. B Bituminous Illinois No. 6 Seam Average No. Averaged High Low High- Vol. C Bituminous Illinois Coals Average No. Averaged High Low Softening temp. °C> 447 39 467 412 390 5 397 377 388 73 433 343 375 3 377 373 387 28 416 357 386 58 413 362 364 18 392 312 Fusion temp. °C. 2 472 31 488 451 423 5 431 412 414 74 456 388 399 3 401 396 414 28 442 390 418 29 431 406 413 10 432 392 Maximum fluid temp. °C. 483 39 499 464 463 5 483 444 442 74 463 420 428 3 435 424 433 28 457 414 425 58 441 404 421 18 437 399 Setting temp. °C. 511 39 526 487 504 5 511 499 481 74 504 456 474 3 487 461 464 28 485 449 456 58 468 442 450 18 465 432 Maximum fluidity dial div./min 12 39 40 1. 2991 5 10,000 723 5004 74 15,000 22 3098 3 4500 1579 73 28 345 12 58 42 1. 20 18 158 1.2 Free- swelling index 3 8.5 45 9.5 6.0 8.5 12 9.0 5.5 6.0 72 9.0 2.5 5.0 2 6.5 3.5 5.0 16 6.0 4.0 4.5 80 6.0 2.5 3.5 54 5 5 1.5 1 Temperature at 0.5 dial divisions per minute. 2 Temperature at 5.0 dial divisions per minute. 3 Values to nearest 0.5 unit. GIESELER PLASTICITY AND FSI VALUES 11 5000 3000 100 73 20 .0" 8.9 H.V."A" (E) I F „ • F H.V. A fILL.l M.V. ' » ■ f w F H. V ' B"(5) H F .V M C" F , L ..V h.v;b",(€ F" F 350' 375' 400' 425° 450° 475' Temperature °C 500* 525' Fig. 3. — Gieseler fluidity and plastic range. The plastic range is the range between the soften- ing temperature and the setting temperature. F is the fusion temperature.