Types Of Coke Research Articles

Electron Microscopic Observation of Carbon Brushes

Surface replicas of several experimental carbon brushes and many commercial carbon brushes for the electrical use were observed by an electron microscope. Brushes of electro-graphitized coke type were composed of flaky clusters of graphite. Sizes of these clusters varied from brush to brush. In brushes of electro-graphitized soot type, graphitized carbon black particles were embedded in the graphite bed of binder coke origin. Sizes of these carbon black particles seemed to be almost the same as those of the original particles.

Crystallite Structure of Cokes from Pitch Fractions.

M a n y carbon products a r e made by mixing c o k e with a binder such a s pitch, shaping t h e mass, and baking t h e product a t a n elevated temperature. To produce carbon e lec t rodes for t h e aluminum industry, a mixture containing 10 t o 35% of pitch and a coke aggregate i s carbonized at 950’ to llOOo C. Several t e s t s have been proposed to determine t h e sui tabi l i ty of p i tches for u s e a s binders in t h e manufacture of carbon products. Martin and Nelson (12) suggested that a good pitch should have a high spec i f ic gravity and carbon-hydrogen ratio. Chare t te and Bischofberger (7) proposed t h e u s e of t h e product of coking va lue t imes carbon-hydrogen ratio. One of t h e most important fac tors is t h e quality of t h e “binder coke” which f o r m s f r o m t h e pi tch during baking. Milliken (11) and Blayden, Gibson, and Riley (4) showed that t h e type of coke depends upon t h e chemical constitution of t h e mater ia ls being carbonized and t h e carbonizat ion procedure. With some except ions t h e more aromatic compounds formed the more graphi t ic cokes. Van Krevelen and Chermin (13) observed tha t t h e yield of coke on carbonizat ion i s greater for aromatic compounds. Ghosh and Riley (9) divided a pi tch into three p a r t s by solvent fractionation and showed that on carbonizat ion the insoluble fraction formed a c o k e with t h e l e a s t graphitic structure. From t h e resu l t s of a modified Kattwinkel t e s t , Briickner and Huber (6) concluded that t h e insoluble fraction a c t s chiefly a s a f i l ler and may even be harmful t o c o k e quality. T h e s e resu l t s l e d to t h e present invest igat ion; for they raised t h e ques t ions of whether a more ex tens ive fractionation of pitch binders would reveal additional var ia t ions in graphitizability, whether any differences ex is ted in graphitizability of corresponding fract ions from different pi tches , and what t h e c a u s e s of such differences were. P i t c h e s a r e tar dis t i l la t ion res idues having cube-in-water melting points above 80’F. (1). They cons is t of a n insoluble phase, t h e C-I fraction, d i spersed in a cont inuous phase. T h e amount determined a s C-I depends upon t h e solvent used in t h e analyt ical procedure-good pitch sol-

Electron Microscopic Observation of Carbon Brushes. I.

Abstract Pitch coke type brushes were found to consist of graphite crystallites having irregular forms and flat surfaces. Sizes of the graphite crystallites were very variable. Well graphitized crystals have relatively flat and smooth surfaces. Less graphitized crystals have rough surfaces. Well-developed flat crystals were split into thin flakes and attached on replica films. Parts of small and badly developed crystallites were seen side by side with the well-developed ones. Carbon black type brushes were found to contain aggregated parts of minute carbon particles and parts of pitch coke origin. The size of the minute particles was approximately the same as that of the original carbon black particles. The minute particles were seen as minute projections or pits on replicas, while they were observed as being linked together to aggregates in directly observed specimens.

Use of Anthracite Fines in By-Product Coke Production: Factors Influencing the Relative Suitability of Different Anthracites for Blending

Abstract The blending of carbonaceous materials, particularly Pennsylvania anthracite, with coking coals as a means of mitigating the acute war shortage of certain types of metallurgical coke, has received considerable emphasis in recent months. However, the desirability of blending anthracite fines with coking coals for by-product coke production has been a matter of considerable controversy. To settle the differences of opinion and judgment, an attempt has been made as reported in this paper to evaluate, at least relatively, some of the variables encountered in the case of anthracite fines. The investigation in question was conducted at the Mineral Industries Experiment Station of The Pennsylvania State College, and was sponsored jointly by the Anthracite Institute and the Commonwealth of Pennsylvania.