The Integrated Scrap Automatic Charging (ISAC) system provides a combination of single bucket practice and continuous charging of scrap from the EAF closed roof by means of a:
- Shredder plant located in the scrap yard area.
- Special conveyor for prowler handling to EAF roof.
- Chemical energy optimization.
- Dedicate melting profile automation system.
The ISAC System increases the profitability of the Meltshop. On the one hand reduces the energy costs because of a low energy start up, fully capped rotor high inertia means smoother operating characteristic and leads to higher throughput of material.
On the other hand the reduction of maintenance means increased plant availability and maximized production. The innovative design allows longer wear part lifetime and reduced required down time for replacement.
Furthermore, the Integrated Scrap Automatic Charging provides advantages that benefit all the melting process:
- Shredder facility provides much cleaner scrap with less pollutants emission.
- EAF melting process yield increase thanks to much cleaner scrap.
- Reduce lime and dolomite in charge.
- Increase the charge mix density.
- Improve the bucket preparation time.
- Reduce energy consumption.
- Recover of non-metallic material.
- Lower power off and faster melting increase the EAF productivity.
- Decrease the needed buckets per heat and less opening of the roof decreases the energy losses.
- Scrap pretreatment by shredder system allows higher flexibility in scrap purchasing policies (optimizing purchasing costs).
- Easier management of the scrap yard (shredder system process the lower quality scrap and the higher quality scrap can be charged in the first bucket).
This could be a typical comparison between standard bucket and ISAC: EAF 70 ton, 100% scrap and input material average density 0,44 t/m3:
PARAMETER STD FEEDING I.S.A.C Tapped Steel (heat size) 70 ton 70 ton Bucket Charging mix 100% scrap 100% scrap I.S.A.C. charged material - 45% EAF Volume 87 m3 87 m3 Nr. of Bucket (roof opening) 3 x 100% 1 x 55% Bucket charging time 6 min 2 min Power off time Base -30% Electrical consumption Base Approx. - 20÷30 kWh/t Metallic yield improvements Base Approx. + 1÷2 % EAF productivity (lower TTT) Base Approx. + 9÷10 %
These diagrams compare the process of only standard charging with the mix of bucket charging + scrap continuous charge (same EAF and same scrap quality, local collected):View the embedded image gallery online at:
The ISAC system consist of different parts that work coordinately from the scrap yard to the EAF 5th hole.
The shredder area is located in open yard. The process starts here. The facilities of this part are able to shred the scrap transforming it into a small pieces of quality scrap, also called proler. This material is charging into uncovered hoppers that feed special inclined conveyors to transport the proler until the next stage, an intermediate storage hopper. The last connection between this external storage hopper and the EAF is made by a belt that conveys the proler towards the inside of the Meltshop, just until the point of being poured into the EAF through the 5th hole.
View the embedded image gallery online at:
- Charging of shredded scrap in hoppers
- Inclined special conveyor for shredded scrap
- Intermediate storage hopper
- Connection to the EAF V hole ISAC System