This page contains a Flash digital edition of a book.
Modern Steel Production Technologies


Typical BOF Products


Steel is the world’s—as well as North


America’s—most recycled material. In the United States alone, almost 69 million tons of steel were recycled or exported for recycling in 2003. Modern steel production relies on two technologies, both of which utlize old steel to make new steel: the basic oxygen furnace(BOF) and the electric arc furnace (EAF).


hollow


structural sections


➮ The basic oxygen furnace (BOF) process uses 25 to 35 percent old steel to make new. It produces products—such as auto- motive fenders, encasements of refrigera- tors, and packaging like soup cans, five-gal- lon pails, and 55-gallon drums—whose major required characteristic is drawability.


➮ The electric arc furnace (EAF) process uses 95-100 percent old steel to make new. It is primarily used to manufacture prod- ucts—such as structural beams, steel plates, and reinforcement bars—whose major required characteristic is strength.


steel studs


Steel recycling has both an economic and envi- ronmental benefit: It is less expensive to recycle steel than to mine virgin ore and move it through the process of making new steel. And today two out of every three pounds of new steel are pro- duced from old steel. However, because steel is such a durable material (that is, cars, appliances, bridges and other steel products last a long time), it is necessary to continue to mine virgin ore to supplement the production of new steel. Economic expansion, domestically and internationally, cre- ates additional demand that cannot be fully met by available scrap supplies.


steel deck


plate purlins


wall studs


Unlike other competing industries, recycling is second nature for the steel industry. The North American steel industry has been recycling steel scrap for over 150 years through the 1,800 scrap processors and some 12,000 auto dismantlers. Many of them have been in the business for more than 100 years.


The pre-consumer, post-industrial, post-con-


sumer, and total recycled content of steel products in the United States can be determined for the cal- endar year 2003 using information from the American Iron and Steel Institute (AISI), the Institute of Scrap Recycling Industries (ISRI), and the U.S. Geological Survey. Additionally, a study prepared for the AISI by William T. Hogan, S.A., and Frank T. Koelble of Fordham University is used to establish pre- and post-consumer fractions of


2


purchased scrap. (Detailed information on these studies can be obtained from the Steel Recycling Institute (call 412.922.2772 or visit www.recycle- steel.org.)


Individual company statistics are usually not applicable or instructive since available scrap typi- cally goes to the closes melting furnace. This open loop recycling allows, for example, an old car to be melted down to produce a new soup can, and then, as the new soup can is recycled, it is melted down to produce a new car, appliance, or structur- al beam.


Basic Oxygen Furnace


BOF facilities consumed a total of 15,772,900 tons of ferrous scrap in the production of 50,941,700 tons of liquid steel during 2003. Based on U.S. Geological Survey statistics, 1,738,800 of these ferrous scrap tons had been generated as unsalable steel product within the confines of these steelmaking sites. In the steel industry, these tons are classified as "home scrap," but are a mix of pre-consumer scrap and post-industrial scrap. Estimates by the Steel Recycling Institute identify about 80% of this home scrap as post-industrial scrap, equating to 1,391,000 tons (1,738,800 x 80%). Additionally, these operations reported that they consumed 148,800 tons of obsolete scrap (buildings and warehouses dismantled on-site at the mill) during this time frame.This volume is clas- sified as post-consumer scrap.


As a result of the above, based on the total scrap consumed, outside purchases of scrap equate to 13,885,300 tons [15,772,900 - (1,738,800 + 148,800)]. According to the Fordham University study, the post-consumer fraction of the purchased ferrous scrap would be 83.4 percent, while 16.6 percent of these purchases would be pre-con- sumer. This equates to 2,305,000 tons of pre-con- sumer scrap (13,885,300 x 16.6%). This "prompt scrap" is mainly scrap generated by manufacturing processes for products made with steel. It is also considered post-industrial scrap.


Therefore, the total recycled content to pro- duce the 50,941,700 tons of liquid steel in the BOF is:


15,772,900 / 50,941,700 = 31.0% (Total Tons Ferrous Scrap / Total Tons Liquid Steel)


Also, the post-consumer recycled content is (13,885,300 - 2,305,000) + 148,800 = 11,729,100


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140  |  Page 141  |  Page 142  |  Page 143  |  Page 144  |  Page 145  |  Page 146