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Extractive Metallurgy of Copper 4th ed. W. Davenport et. al. (2002) Episode 11

Tham khảo tài liệu 'extractive metallurgy of copper 4th ed. w. davenport et. al. (2002) episode 11', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Melting and Casting 377 The Hazelett twin-band caster is shown in Fig. 15.3 in its role as an anodecasting machine. Molten copper is fed from a pour pot into the space between two sloped moving steel bands. The bands are held apart by moving alloyed copper dam blocks on each side creating a mold cavity ranging between 5-15 cm in width and 5-10 cm in thickness. Both separations are adjustable allowing variable product size. Solidification times are similar to those of the Southwire and Properzi machines Strand et al. 1994 . The three types of moving-band casting devices have several features in common. All require lubrication of the bands and mold wheel or dam blocks using silicone oil or acetylene soot Adams and Sinha 1990 . Leftover soot is removed from the bands after each revolution then reapplied. This ensures an even lubricant thickness and a constant heat transfer rate. Fig. 22.4. System for controlling molten copper level in Southwire continuous casting machine Adams and Sinha 1990 . Reprinted courtesy TMS. 378 Extractive Metallurgy of Copper Table 22.5. Operating details of Hazelett and Southwire continuous casting machines 2001. Casting plant Nexans Canada Phelps Dodge Refinery Norddeutsche Affinerie Palabora Mining Casting machine Hazelett Hazelett South wire Southwire twin band twin band wheel band wheel band Bar size cm X cm 7x13 7 X 13.2 5.8 X 11.7 2.15 X 15 Casting rate of this bar 48 63 45 21.5 tonnes hour Molten copper level electromagnetic electromagn- X-ray infrared scan- control in caster pool level etic pool level ner Casting temp. C measurement 1125 measurement 1130 1110-1125 1100-1130 Bar temperature -950 1015 900 890-930 leaving caster C Target o in copper ppm 250 250 160-250 180-250 measurement Electro-nite cell Leco on rod Lcco Leco on rod technique control system in launder Tempolab in holding furnace Leco on rod manual compressed protective gas holding fur- Wheel and band details wheel diameter m rotation speed rpm rim materials rim life