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IRONMAKING
Fig 4. GRANSHOT metal granulation directly from torpedo ladle car at TATA KPO
Granulation capacity
Torpedo capacity
Power input from metal
Water cooling capacity
Plant foot-print (incl. hot well)
128 MW
22 x 27 m
Nominal Design 300 tph
360 tph
300 ton
128 MW
GPI product properties The rapid quenching of the granulated material results in a product with analysis identical to that of liquid pig iron. No change in composition has been found to take place during the granulation process. The chemistry of the product can, therefore, be specified by ingoing liquid metal analysis. The granulated material has a spherical deformed shape. Some typical granulated pig iron material is seen in Fig.6. The granule size distribution is typically in the range 3mm to 50 mm, with the main fraction between 5mm and 30 mm. The material has a high bulk density, ~ 4000 kg/m3 and an angle of repose over 35 degrees. The granule shape and size give a material with excellent preheating properties and a fast melting/dissolution when added to metallurgical processes. This has also been discussed in previous papers [3,4] .
Table 1. GRANSHOT plant key figures for TATA KPO
30 seconds. The operator is, at all times, assisted by the control system to ensure a safe and stable granulation process. The granulation process and the discharge of the granulated product at TATA KPO is shown in Fig. 4 and Fig.5. A summary of key figures for the TATA GRANSHOT plant is shown in Table 1. Operational experiences Since the commissioning of the GRANSHOT plant in March 2016 more than 250kt of granulated metal have been produced (in February 2017). During the initial months after start-up of the blast furnace most of the pig iron was taken through the GRANSHOT plant. Since August 2016 the steel plant has been in full operation and the granulation facility is used more intermittently, whenever excess pig iron is available. The number of torpedoes handled in a sequence varies depending upon available metal, ranging from granulation of a single torpedo up to several torpedoes in a row. The maximum number of torpedo ladles handled so far in one sequence, using the same tundish, is 10, which corresponds to approximately 3kt of hot metal. Granulated pig iron, GPI – TATA Ferroshots The granulated pig iron product, referred to as GPI, is marketed by TATA as Ferroshots. January/February 2018
ironmaking granshot.indd 3
Within a few months of its launch the product has received a lot of interest from the steel industry and to date around 160kt of Tata Ferroshots have been sold to customers in India, Asia and Europe. The end use of TATA Ferroshots includes electric arc furnaces (EAFs), induction furnaces, cupolas, basic oxygen furnaces (BOFs) and foundries as a replacement of pig iron (pigs), scrap or DRI. Granulated pig iron is characterised as a homogeneous virgin iron product with several beneficial properties, which is further discussed below.
Easy handling of granulated product The granule size and shape allows for easy handling of the product and this makes it suitable for handling with most raw material systems, such as conveyor belt, magnet, front-end loader, bin systems and skips. Examples of handling and loading of granulated product at TATA KPO is seen in Fig.5 and Fig. 7. From the intermediate storage area nearby the granulation unit the granules are loaded on to a truck by front-loaders and taken to the main storage area for further loading and transport to customers.
Fig 5. Granule discharge from conveyor to intermediate stockpile
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22/01/2018 08:36:31