Brief Introduction of the Iron Making
BBN Steel launched the 1.2 billion yuan total investment Iron Making Project in July, 2007 in order to solve the problem of raw material supply for the EAF steel making for the MPM production line, to enhance the steel quality and cleanness, to realize choice material supply and reduce energy consumption, to realize upgrading of product structure, and to speed up the progress in building BBN Steel into a world first class, professional seamless steel tube producer. The project includes a new 1,000 m3 blast furnace with average annual utilization coefficient of 2.357t/(m3.d), and annual output of 825,000 tons of iron, one 130 m2 sintering machine with utilization coefficient of 1.35t/m2.h, and annual sintering output of 1,389,000 tons.
The material charge for the blast furnace adopts the technology of high efficiency ore and coke vibration screen, and the charging material are recycling egg coke mixed with the sintering. The working volume is 1,000 m3, stout type; the hearth diameter is 7.7m, with twenty tuyere; the furnace roof is adopted a series hoppers Bell-less top and a rotating chute distributing , the hopper volume is 22.3m3 , furnace body is covered with the full cooling stave , carbon block and ceramics for the under hearth and hearth structure, the tuyere are built by the composite Brown fused alumina brick, AlB2BOB3B-C-SiC combined bricks are applied for the iron notch; three high temperature long life roof ignition hot blast stoves are laid in one line; residual heat collection equipment is used, with the residual heat being able to support the air and mixed gas combustion; the hot blast temperature is 1200~1250℃, and the laid brick non-maintenance life is ≥ 25 years.
There is no combustion chamber for a roof ignition-type hot blast stove, the usage rate of the effective checker chamber’s area is improved, the checker hole diameter of the checker chamber is Φ30mm, the heating area is 84.0m2/m3 with a very high heat exchange area; the cast house is rectangular shape, four choke plugs railway which control the hot metal discharging are arranged, 100 tons hot metal tank transfer car is used for transporting the hot metal, with a total area of 2,000 m2; the angle between the two tap holes is 80°, each tap hole has their independent clay gun, tapping machine and oscillate out spout and other equipment.
Double pulverized coal injection hoppers, major injection pipe plus distributor in front of furnace are adopted for the pulverized coal injection system to directly injection into the blast furnace; one single series full negative pressure milling system is used; single medium speed grinding mills with maximum output force of 21t/h, normal output force of ≥ 16t/h is applied; AV56-14 full static electrical axial flow blast blower with adjustable vanes is used for the blast station, the annual blast volume is 2,627 m3/min., the blast pressure at the exit is 0.45MPa, the 10kV asynchronous motor is in position with a power of 14,500kW.
The crude gas gravity dust catcher and dry bag filter are used for gas purifying; international advanced Jiacheng water slag treatment is used for the slag treatment.
The technical flow collocation such as pre-crushing of the fuel, material proportioning, mixed grain making, material distribution, sintering, crushing, cooling, crush screening, the sampling for the sintering, testing, and storage are reasonable - the flow and logistics are smooth.
The 130 m2 sintering was designed based on a series of historical experiences on successful sintering, based on the adoption of further advanced technologies, and based on the practical sintering production in domestic industries. The maximum treatment capacity is 468 t/h；the water cooling axis type single roller crusher with the size ofφ1700×2900 is installed in the end of the sintering strand, and the hot sintering grain size after crushing is less than 150mm, and the maximum crushing capacity is 405t/h.
In addition, for environmental protection, the project takes “Pollution Prevention is a priority, combining Anti-Pollution with Treatment” and “Clean Production, Sustainable Development” as guidelines, conducted full process control for production as well as anti-pollution and environmental treatment, apply new techniques, new technologies, new equipment as to improve the utilization of resources and energy, eliminating the maximum amount of pollution during the production process.
The investment in environmental protection facilities – including waste water treatment, waste gas treatment facilities, noise treatment facilities and afforestation etc. – amounts to 230 million Yuan, or 19.8% of the total investment.