the United States are centered in integrated plants. 

 Tiiese have generally been located in the midwest 

 and east where major water sources are available. 

 A few mills have been built in water-short areas 

 because of economic advantages which outweighed 

 the increased cost of recirculating water. The 

 major processes involved in the manufacture of 

 steel all require process water, some in several 

 ways. The succeeding paragraphs present a brief 

 description of the process and the process use of 

 water. 



The production of coke involves the heating of 

 coal in the absence of air in order to rid the coal of 

 tar and other volatile products. Process water is 

 used in the direct cooling of the incandescent coke 

 after removal from the coke oven in a process 

 called coke quenching. This quenching process is 

 nothing more than dousing the coke with copious 

 amounts of water. 



Pig iron production is accomplished in the blast 

 furnace. Process water is used to cool or quench 

 the slag when it is removed from the furnace. The 

 major use of process water in the blast furnace is 

 for gas cleaning in wet scrubbers. Steel is manu- 

 factured in open hearth or basic oxygen furnaces. 

 Process water may be used in gas cleaners for 

 either of these furnaces. 



The major products of the steelmaking processes 

 are ingots. Ingots, after temperature conditioning, 

 are rolled into blooms, slabs, or billets depending 

 upon the final product desired. These shapes are 

 referred to as semifinished steel. Water is used for 

 cooling and lubricating the rolls. These semi- 

 finished products are used in finishing mills to 

 produce a variety of products such as plates, rails, 

 structural shapes, bars, wire, tubes, and hot strip. 

 Hot strip is a major product and the manufactur- 

 ing process for this item will be briefly described. 



The continuous hot strip mill receives tempera- 

 ture conditioned slabs from reheating furnaces. 

 Oxide scale is loosened from the slabs by mechani- 

 cal action and removed by high pressure jets of 

 water prior to a rough rolling stand, which pro- 

 duces a section that can be further reduced by the 

 finishing stand of rollers. A second scale breaker 

 and series of high-pressure water sprays precede 

 this stand of rolls in which final size reductions are 

 made. Cooling water is used after rolling for cool- 

 ing the strip prior to coiling. Most hot-rolled strip 

 is pickled by passing the strip through solutions of 

 mineral acids and inhibitors. The strip is then 

 rinsed with water. 



Much hot-rolled strip is further reduced in 

 thickness in cold rolls in which the heat generated 

 by working the metal is dissipated by water sprays. 

 Palm oil or synthetic oils are added to the water 



for lubrication. After cold reduction, the strip is 

 often cleaned by using an alkaline wash and rinse. 

 Tin plate is made from cold-rolled strip by either 

 an electrolytic or hot-dip process, most commonly 

 by the former. The electrolytic process consists of 

 cleaning the strip using alkaline cleaners, rinsing 

 with water, light pickling, rinsing, plating, rinsing, 

 heat treating, cooling with water (quenching), 

 drying, and coating with oil. The galvanizing or 

 coating of steel strip with various other products 

 is carried out basically by the same general scheme 

 as tinning. 



The volume of water used in the manufacturing 

 of steel is a variable which depends on the quantity 

 and quality of the available supply. The quantity 

 presently being used varies from a minimum of 

 about 1,500 gal/ton of product, where water is 

 reused intensively, to about 65,000 gal/ton, where 

 water is used on only a once through basis. Both 

 of these figures include total water utilized, not 

 just process water. These figures contrast the range 

 of water intake between plants in areas having: 

 (1) extremely limited, and (2) almost unlimited 

 water supplies. 



The only definitive information available to the 

 task force on the amount of process water required 

 as compared with other water uses was found in 

 the census of manufacturers (7). The following is 

 a summary of this information for 1964 for the 

 steel industry (SIC 331). 



Water use: Volume, bgy 



Intake water 4,051 



Process water 885 



Cooling 3,008 



Boiler feed, etc 159 



This tabulation indicates that only 22 percent 

 of the water taken into a steel plant is termed 

 process water. Representatives of the industry 

 have indicated that process water may account 

 for as much as 30 to 40 percent of the total water 

 intake. 



Recycling of water is receiving much attention 

 from the industry as a method to reduce water 

 utilization, reduce stream pollution, and minimize 

 the cost of controlling this pollution. Although in- 

 dividual plants within the iron and steel industry 

 have been practicing reuse of water to varying 

 degrees for some years, the major changes are yet 

 to come. According to the Census of Manufac- 

 tures, the gross water used in the industry in 1964 

 was approximately 5,800 billion gallons. This 

 gross water use when compared with a water 

 intake of about 4,000 billion gallons indicates 

 that 1,800 billion gallons were reused. This quan- 



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