GB508008A - Improvements in or relating to the manufacture of carbon for electrical and other purposes - Google Patents

Abstract

508,008. Carbon electrodes and other articles. CLOUD, W. A. Nov. 23, 1937, No. 32244. [Class 90] Carbon for electrodes and other articles is made by mixing finely ground anthracite coal having a fixed carbon content of approximately 90 per cent and 1 per cent ash, bituminous coal, calcined flame lamp black and petroleum still coke with coal tar and/or pitch as binding agent, reducing the mixture to a plastic mass by heat, moulding or extruding the mass to the desired shape and then baking the articles, the process being initiated at a temperature of 212‹ C. and carried on thereafter at a gradually increasing temperature, up to an optimum of about 2,000‹ F. For a softer grade of carbon, caramel from cane sugar or carbonised sugar may be used as a binder instead of the coal tar or pitch, and if desired, foliated graphite may ,be incorporated in the mixture. Preferably the powdered mixture is washed to remove impurities, dried and then mixed with the binder, again reduced to powder and then made plastic by heating, and finally pugged under pressure at about 220‹ F. A suitable mixture is 6 lbs. anthracite ; 3 lbs. bituminous coal; 2 lbs. coke; 1 lb. lampblack and 28-35 lbs. binder. These proportions may be varied according to the mechanical strength required. The product is suitable for making electrodes, plates, slabs, crucibles, furnace linings and similar. articles. Specification 15782/94, [Class 90], is referred to.