NTMK Nizshnly Tagil turns up the heat to construct blast furnace in icy winter
Spraycast and injection of newly constructed blast furnace, by Dmitriy Povalyaev, Sales Manager in Urals Eastern region, Calderys
Russia’s NTMK Nizshnly Tagil, part of the global Evraz Group, scheduled Greenfield construction for a new blast furnace during a harsh winter in the Ural Federal District. The goal was to have it running by the end of winter. This is how we tackled this challenge.
In late January of 2018 NTMK Nizshnly Tagil and our team brainstormed options to create normal working conditions in hostile weather. This resulted in a novel breakthrough. The BF shell would be insulated from the outside in, enhanced by heating fans in tuyeres. The result was a leap from -25ºC to +25ºC inside the furnace shell.
Construction and installation productivity was optimized, and all equipment was easier to handle, being arranged on casthouse with a unique wooden cover built around it. This way heating fans could easily create the desired temperature inside, so that working conditions were normal, and materials warmed up. Another novel idea was having a truck-crane on the casthouse at all times, as well as providing helpers for big-bag operations to minimise the number of platform lifts.
The project scope of installation from level +14890 to +37200 with thickness from 475 to 120 mm required different quantities of castables: 290 tonnes of CALDE® SPRAYCAST SIC 15 R in bosh, belly and lower stack; 121 tonnes of CALDE® SPRAYCAST SIC 7 R in upper stack by manual shotcreting; 171 tonnes of CALDE® INJECT MF 50 G3 injected in the gap between staves and BF shell.
Spraycast was installed onto the surface of staves equipped with metallic anchors. Cards were wrapped with 3-mm ceramic fiber paper in order to create compensation joints and allow for free movement of each separate card. For the whole stack, 1500 V-shaped alloy steel anchors were installed into grooves of cooper staves, 960 Y-shaped metallic anchors were welded onto iron staves and 360 m2 of Ceramic fiber paper for compensation joints. Rebound was collected in empty big bags on the platform by the Calderys team. The quantity was less than 2% against a declared limit of 5%. Spraycast of the whole stack required only 12 movements of the platform inside the BF, both a productivity and safety advantage. The platform was lifted up during the night shift, as our team worked during the day. This working schedule was accomplished by only ten members of the Calderys Russia installation team, including supervisors.
Safety is at the heart of everything we do. Safety protocols were developed by Calderys and agreed with NTMK prior to the beginning of the project. The access for our people inside BF -7 was organised via a maintenance door with a bell-less top. The ladder coming down to the platform was equipped with a safety guard and intermediate landing platforms. Regular safety inspections were held by NTMK EHS services with no remark or penalty written to Calderys. Injection was done from outside BF -7 from down to upper nipples welded in accordance with our scheme for better control of the gap filling.
The BF -7 started up in February 2018, ahead of schedule. EVRAZ NTMK met their objective for quality of lining and rebound (2% against 5% acceptable limit). The new blast furnace is now continuously producing 7000 tonnes of high-vanadium iron — one of only two mills in the world to do so.
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Editorial support from Martin Koepenick, Innova.