. Transactions of the Institution of Mining Engineers . orncliffe Coal; and (B) SameCoal Mixed with 40 per cent, of Coke-breeze. coal side by side in a furnace. Fig 4 (A) and (B) shows photographsobtained from experiments of this kind. Charge (A) consisted of Thorn-cliffe coal, and charge (B) of the same seam with 40 per cent, of breeze added. Both wereput into the muffletogether at a tempera-ture of 900° Cent.,and were withdrawnafter 15 minutes(normally, 40 minuteswould be required tocomplete carboniza-tion). It will be seenthat (B) is carbonizedpractically to thecentre, while the heathad not
. Transactions of the Institution of Mining Engineers . orncliffe Coal; and (B) SameCoal Mixed with 40 per cent, of Coke-breeze. coal side by side in a furnace. Fig 4 (A) and (B) shows photographsobtained from experiments of this kind. Charge (A) consisted of Thorn-cliffe coal, and charge (B) of the same seam with 40 per cent, of breeze added. Both wereput into the muffletogether at a tempera-ture of 900° Cent.,and were withdrawnafter 15 minutes(normally, 40 minuteswould be required tocomplete carboniza-tion). It will be seenthat (B) is carbonizedpractically to thecentre, while the heathad not penetrated toa greater depth thanI inch in (A); thecore of the latter wasquite unfused, andfell away as increased conductivity is, therefore, not due solely to thepresence of carbon in the form of fine coke, but also to the destruction ofthe decomposition zone as a result of utilizing the surplus cementing-material to bind the inert coke. This zone will also disappear if thebinder is partly destroyed by other means. Fig. 5 shows a charge of. Fig. 5. ■Welsh Coal specially treated to reducethe Decomposition Zone. 1921-1922.] ROBERTS CARBONIZATION OF COAL AT LOW TEMPERATURE. 17 the same coal as that in Fig-. 3 (A) which had been siibjeetecl to a pre-liminary treatment, but to which no breeze had been added; while Fig. 6shows the coke from an untreated Wrexham coal which normally contractson heating. The corresponding curves are shown in Fig. 7. Application of Coke-hreeze.—Results similarto those described wereobtained with other coalsmixed with coke. It willbe seen, therefore, thatthe beneficial effect of thisprocess is two-fold—(1) itprevents the expansion ofcoal, and (2) increases theconductivity of the charge,thus reducing the timerequired for proportion of inertmatter to be added mustbe determined in thelaboratory. With every strongly caking coal there will be a certainpercentage of breeze which will give the best results. The addition ofmore t
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Keywords: ., bo, bookcentury1800, bookdecade1890, booksubjectmineralindustries
