Blast furnace slag granulation at cast house May05

Blast furnace slag granulation at cast house...

Blast furnace slag granulation at cast house Blast Furnaces normally generate 250 to 350 Kg of liquid slag for every ton of hot metal produced. This molten slag is at around 1400 Р1550 deg C temperature.  Till seventies blast furnace (BF) slag was considered a waste product and was being dumped at a convenient place away from the blast furnace.  During early seventies granulation of molten slag with high pressure water started near the slag dumps. The processes of granulation of molten slag were developed during late seventies and early eighties. The processes differ in the method of dewatering of the wet granulated slag. Today granulation of molten BF slag is the well accepted technology and is being used in most of the blast furnaces around the world. In India the credit of commissioning the first cast house slag granulation plant goes to Visakhapatnam Steel Plant when the first blast furnace of the plant was commissioned on 28th march 1990. Major slag granulation processes presently under operation are OCP granulation system, Gipromez designed plants, Rasa system and INBA slag granulations plants of Paul Wurth, modified INBA process or IDE process etc. Concept of slag granulation The process of slag granulation involves pouring the molten slag through a high pressure water spray in a granulation head, located in close proximity to the blast furnace. Granulation process is the controlled quenching of the slag in cold water which does not give time for crystalline growth to take place. Large volume of water is required (10 parts of water to 1 part of molten slag being optimum). During this process of quenching, the molten slag undergoes accelerated cooling under controlled water flow condition and gets converted into glassy sand with 97 % of the solid granulated...