Water requirements of the carbon-black industry

Abstract

Carbon blacks include an important group of industrial carbons used chiefly as a reinforcing agent in rubber tires. In 1953 more than 1,610 million pounds of carbon black was produced, of which approximately 1,134 million pounds was consumed by the rubber industry. The carbon-black industry uses small quantities of water as compared to some industries; however, the water requirements of the industry are important because of the dependence of the rubber-tire industry on carbon black. Two methods are used in the manufacture of carbon black - contact and furnace. The only process use of water in the contact method is that used in pelleting. Water is used also in the plant washhouse and for cleaning, and sometimes the company camp may be supplied by the plant. A survey made during the last quarter of 1953 showed that the average values of unit water use at contact plants for process use, all plant uses, and all uses including company camps are 0.08, 0.14, and 0.98 gallon of water per pound of carbon black respectively. In addition to use in wet pelleting, large quantities of water are required in continuous and cyclic furnace methods to reduce the temperature of the gases of decomposition in order to separate and collect the entrained carbon black. The 22 furnace plants in operation in 1953 used a total of 12.4 million gallons per day for process use. Four furnace plants generate electric power for plant use; condenser-cooling water for one such plant may nearly equal the requirements of the entire industry for process use. The average values of unit water use at furnace plants for process use, all plant uses and all uses including company camps but excluding power generation are 3.26, 3.34, and 3.45 gallons of water per pound of carbon black respectively. Carbon-black plants in remote, sparsely settled areas often must maintain company camps for employees. Twenty-one of twenty-seven contact plants surveyed in 1953 had company camps. These camps used large quantities of water: 0.84 gallon per pound of carbon black as compared to 0.14 gallon per pound used in the plants. Furnace plants can generally be located near a labor supply and, therefore, do not require company camps. Ten of the twenty-two furnace plants surveyed in 1953 had company camps. Because water used for pelleting and gas quenching is evaporated, leaving the dissolved minerals in the product as objectionable impurities, particular attention was paid to the quality of water available for use at the plants visited during the 1953 survey. Reports of chemical analyses of water samples were obtained at 23 plants. A study of these reports does not develop a pattern of the limits of tolerance of dissolved solids in water used in process or of the need for water treatment based on geographical location of the plant. However these analyses show that water used for quenching contains less dissolved solids than water used by the industry for any other purpose. Based on trends in the industry it is expected that the quantity of water used by the carbon-black industry will increase more rapidly than will the quantity of carbon black produced because of the increasing percentage produced in furnace plants, and that selection of sites for modern furnace plants will be influenced more by quantity and quality of the available water supply than was the case in selecting sites for contact plants for which low-cost natural gas was the primary consideration.