Bulletin . site) board three-fourths inch thick, which wascut to fit snugly into the sheet-iron shell of the furnace. The space 102 FUSIBILITY OF COAL ASH. between the silica tube and the shell was packed with kieselguhr(infusorial earth). The sheet-iron cylindrical jacket was 10 inchesin diameter and 17^ inches long. Oxygen was supplied from a tankthrough a rubber tube and a bubbling bottle at the rate of 3 to 5bubbles per second, the rubber tube being connected to the silica tubeat b. Before the ash was ignited it was ground for 20 or 30 minutes ina mechanical agate mortar grinder, which red
Bulletin . site) board three-fourths inch thick, which wascut to fit snugly into the sheet-iron shell of the furnace. The space 102 FUSIBILITY OF COAL ASH. between the silica tube and the shell was packed with kieselguhr(infusorial earth). The sheet-iron cylindrical jacket was 10 inchesin diameter and 17^ inches long. Oxygen was supplied from a tankthrough a rubber tube and a bubbling bottle at the rate of 3 to 5bubbles per second, the rubber tube being connected to the silica tubeat b. Before the ash was ignited it was ground for 20 or 30 minutes ina mechanical agate mortar grinder, which reduced the ash to 200mesh and finer. Five to ten grams of this finely ground ash wasplaced in a silica or porcelain capsule d If inches in diameter andfive-eighths inch deep, and was transferred to the furnace. Six ofthese could be placed in the furnace at one time. The open end ofthe furnace was closed with a snugly fitting plug of transite. Thethermocouple was inserted through a hole in this plug. After one. Figure 35.—Electric furnace for igniting ash in atmosphere of oxygen. or two runs with the thermocouple, the temperature could be esti-mated with sufficient accuracy by the eye. In heating this furnace from room temperature to 800° C., a cur-rent of 5 amperes was used during the first 10 minutes: and then 10amperes until 800° C. was reached, 30 to 40 minutes being requiredin all. Five to six amperes was required to maintain the temperatureat 800° C. The maximum voltage was 110 volts. This method of ignition was used in all subsequent experiments. INFLUENCE OF SIZE AND SHAPE OF CONE. The ordinary Seger cone used in the ceramic industries is so pro-portioned that on softening it describes a smooth bend or half circle,the tip touching the base. In the early part of this investigation itwas found that similar cones made of molded coal ash did not, asa rule, bend as uniformly as the standard Seger cones. Certain ashes FUSIBILITY OF COAL ASH AS DETERMINED IN GAS FURNACE. 103
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
