Blast Furnace Tuyeres and Tuyere Stocks May29

Blast Furnace Tuyeres and Tuyere Stocks...

Blast Furnace Tuyeres and Tuyere Stocks The blast furnace (BF) has the objective of extracting the hot metal (liquid iron) from iron ore lump, sinter and/or pellet, coke and injected fuel. This objective is achieved by passing a hot enriched air flow (hot blast air) through the ore and coke burden which goes down in the internal column of the BF. The hot blast air and auxiliary fuel are injected into the blast furnace through tuyeres located around the perimeter of the BF. The upper zone of the hearth wall of the blast furnace contains the openings for the tuyeres which are used to introduce the hot blast air into the furnace. The furnace jacket in the tuyere zone contains steel reinforced openings within which copper (Cu) cooled elements are installed, similar to that shown in Fig 1. The steel reinforcements in the jacket are called tuyere cooler holders. The large Cu cooler which is installed within the machined inner surface of the cooler holder is called the tuyere cooler. The Cu cooler which actually introduces the hot blast air into the furnace is called the tuyere. It is installed within a machined, inner seating surface on the tuyere cooler. The blowpipe is part of the tuyere stock air distribution piping, which delivers the hot blast air from the bustle pipe, and which mates with the tuyere, to direct the hot blast air into the furnace. The tuyere breast walls are usually made of carbon brick and the cooling is generally external with jacketed cooling channels on the outside of the shell. Some furnaces have internal staves in the tuyere breast between the tuyere coolers as a cooling design for the tuyere breast. Fig 1 also shows the arrangement of the tuyere cooler holder,...

Copper in Steels

Copper in Steels  Copper (Cu) provides interesting alloying advantages to steel and steel welds. Cu (atomic no. 29 and atomic weight 63.54) has a density of 8.96 gm/cc. The melting point of Cu is 1083 deg C while the boiling point is 2570 deg C. Cu is normally added to steel to increase corrosion resistance. Experimentation with the addition of Cu to structural steels for its ability to impart good atmospheric corrosion resistance properties began in the year 1916 in the USA. The first commercial use of Cu bearing steel as atmospheric corrosion resistant steel was during the period 1933 to 1935. Cu is beneficial to atmospheric corrosion resistance when present in amounts exceeding 0.20 %. The atmospheric corrosion resistance steels are also called weathering steels. Addition of Cu in steelmaking Cu is added to steel in the form of pigs, refined ingots or as copper and nonferrous alloy scrap. Any Cu already present in the steel scrap charge is carried over into the liquid steel with little or no loss. Scrap electric motors containing usually 10-15 % Cu are often used as a source of Cu during steelmaking. Cu can be added either in the steelmaking furnace or in the teeming ladle. Both techniques of Cu addition give very high recoveries. Losses, if any, are due to the mechanical reasons. When addition of Cu is made in the steelmaking furnace, it should be done before the end of decarburization. Effects of copper on steels The ability of Cu bearing steel to withstand atmospheric corrosion is not the major reason which provides the impetus for the development of Cu bearing steels today. Until recently, it was not fully recognized that along with the improved corrosion resistance, the precipitation of Cu can make a significant...