
af38ac8a86fea32e9831a666629b49b2.ppt
- Количество слайдов: 26
1 EVALUATION OF IRON ORE SINTERS AND PELLETS FOR BF AND DR USE Presented by: MS Mashao Kumba Iron Ore A member of the Anglo American plc group
OVERVIEW 2 • List of most popular tests performed: – – – – Tumble Strength (ISO 3271) Crushing Strength (ISO 4700) Swelling Index (ISO 4698) Size range Reducibility (ISO 4695) Relative Reducibility (ISO 7215) Reduction Disintegration (ISO 4695) Reduction Disintegration and metallization for DR feedstock (ISO 11257) A member of the Anglo American plc group
OVERVIEW 3 • List of most popular tests performed: – – – Corex tests REAS (Reduktion Erweichung und Abschmelzung) Drop tests A member of the Anglo American plc group
PHYSICAL PROPERTIES 4 • Important properties – – – Size distribution Strength Degradation A member of the Anglo American plc group
PHYSICAL PROPERTIES 5 Transport Screening Blast Furnace Top Shaft 500 °C Middle Shaft 950 °C Bosh 1100 °C Bosh +1300 °C A member of the Anglo American plc group
PHYSICAL PROPERTIES 6 • Tumble Strength – – – Percentage of + 6. 3 mm fraction gives TI Percentage of – 0. 5 mm fraction in gives AI Criterion of acceptance: Ø Ø 70% for TI Less than 5% for AI A member of the Anglo American plc group
PHYSICAL PROPERTIES 7 • Compression Strength – Criterion of acceptance: Ø 250 kg/pellet A member of the Anglo American plc group
PHYSICAL PROPERTIES 8 • Characterize material susceptibility to: – – Breakage Degradation A member of the Anglo American plc group
METALLURGICAL PROPERTIES 9 • Important properties – – – Reduction Disintegration Reducibility Swelling Sticking Softening and melting A member of the Anglo American plc group
METALLURGICAL PROPERTIES 10 Transport Screening Blast Furnace Top Shaft 500 °C RDI Middle Shaft 950 °C RI &RR Bosh 1100 °C Bosh +1300 °C REAS & RUL REAS A member of the Anglo American plc group
REDUCTION DISINTEGRATION 11 • • • RDI for blast furnace RDI for Midrex RDI for Corex A member of the Anglo American plc group
REDUCTION DISINTEGRATION 12 Blast Furnace % - 3. 15 mm < 40 % - 0. 5 mm Direct Reduction <5 Acceptable Preferred % -3. 36 5 Max. 2 % Metallization 91 Min 93 A member of the Anglo American plc group
REDUCTION DISINTEGRATION 13 – – – – Decrease in burden permeability Poor gas distribution Scaffolding Increases fuel consumption Lower productivity Increased dust load in off gas Material more susceptible between (400600)°C A member of the Anglo American plc group
REDUCIBILITY 14 Transport Screening Blast Furnace Top Shaft 500 °C Middle Shaft 950 °C RI & RR Bosh 1100 °C Bosh +1300 °C A member of the Anglo American plc group
REDUCIBILITY 15 • • Reducibility Index Relative Reducibility A member of the Anglo American plc group
REDUCIBILITY 16 • Reducibility for sinters generally higher – – • Typical values for sinters (1. 1 -1. 4)%/min Typical values for pellets (0. 8 -1. 4)%/min Final degree of reduction: – – Typical value for sinters (60 -70)% Typical value for pellets (50 -60)% A member of the Anglo American plc group
REDUCIBILITY 17 • Productivity requires reducible feedstock Reducibility depends on: • – – – Porosity Surface area Gas-solid contact A member of the Anglo American plc group
FREE SWELLING INDEX 18 • General criterion for acceptance: – – Swelling not be higher than (25 -30)% Noted that alkalis promote excessive swelling A member of the Anglo American plc group
FREE SWELLING INDEX 19 • Increase in volume which in turn decreases voids in charge – – Impedes gas flow Pressure drop A member of the Anglo American plc group
STICKING INDEX 20 • • Impact on maximum bustle gas temperature Bustle temperature determines overall productivity A member of the Anglo American plc group
METALLURGICAL PROPERTIES 21 Transport Screening Blast Furnace Top Shaft 500 °C Middle Shaft 950 °C Bosh 1100 °C Bosh +1300 °C REAS A member of the Anglo American plc group
REAS 22 • • • Ideal BF conditions Temperature profile increases from ambient to 1600°C in 8 hrs Sample subjected to a fixed load A member of the Anglo American plc group
REAS 23 – – – – Softening temperature Melting temperature Dripping temperature Differential pressure (d. P) Degree of reduction at time and temperature Compaction at time and temperature Mass of dripping melt at time A member of the Anglo American plc group
REAS 24 A member of the Anglo American plc group
REAS 25 • General criterion for acceptance: – – – Cohesive zone should be small but at high temperatures Relative drip mass at least 70 per cent Shape of d. P curve • Width • Height • Position of peak(s) A member of the Anglo American plc group
PELLET vs. SISHEN 20 mm Pellet 20 mm ore 9 x 16 mm 85 % - Min 95% – Pref. 83. 5 % Fines 5 % Max < 3% Pref. 3. 9 % % + 6. 3 mm 92 % 88 % - 0. 5 mm 6 4. 4 % Metallization 98 98 % Clustering 0 0 % Metallization 91 95 % < 3. 36 5 2. 4 (10) 240 205 26 Size Range Tumble Strength Hot Load Linder Price $/tonne A member of the Anglo American plc group