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Age (days)

FIGURE 1.30 Development of compressive strength with age for solid brick groups at 100 percent slag replacement levels. (Source: Y. Kourany and S. M. El-Haggar, "Utilizing Slag Generated from Iron and Steel Industry in Producing Masonry Units and Paving Interlocks," 28th CSCE annual conference, June 7-10, 2000, London, Ontario, Canada.)

were reached for all masonry groups at 28-day age compared to the control and commercial bricks as seen in Figure 1.30. All test groups showed higher compressive strength than the ASTM limit of 4.14 MPa for nonload-bearing units. At slag replacement levels higher than 67 percent, all groups resulted in compressive strength higher than the ASTM requirement of 13.1 MPa for load-bearing units. All slag types resulted in paving stone interlocks having water-absorption values far below the ASTM limit, as shown in Figure 1.31. All slag paving stone interlocks showed higher compressive strength and abrasion resistance than the control specimens made of dolomite. Moreover, the proposed fields of application were found to be safe to the environment and have no drawbacks based on the heavy metals content and water-leaching test results.

Szekely proposed a comprehensive research program to reduce fume formation in the BOF and EAF, find an effective approach to reduce and utilize steel-making slag, and to effectively use the oily sludge produced in rolling mills.44 Related environmental problem areas were discussed and preliminary solutions were identified. From Szekely's viewpoint, although several technologies are available for treating EAF dust, they are quite expensive, and satisfactory solutions for the EAF dust problem have not yet been produced. He suggested some possible solutions worthy of exploration, such as modifying the charging, blowing, and waste gas exhaustion system to minimize dust formation. Another proposed solution is to examine the composition of the dust produced during different phases of furnace operation and, if appropriate, segregates the recovered dust.

Some of the methods used to turn steel plant dust into a valuable raw material were described by one of the solid waste processing companies in its article published 1997.54 One of the commonly used methods is micropelletizing, where dust is mixed with lime as a binder and is pelletized to produce a fine granular

FIGURE 1.31 Comparison between absorption ratios of the different slag types with replacement level. (Source: Y. Kourany and S. M. El-Haggar, "Utilizing Slag Generated from Iron and Steel Industry in Producing Masonry Units and Paving Interlocks," 28th CSCE annual conference, June 7-10, 2000, London, Ontario, Canada.)

FIGURE 1.31 Comparison between absorption ratios of the different slag types with replacement level. (Source: Y. Kourany and S. M. El-Haggar, "Utilizing Slag Generated from Iron and Steel Industry in Producing Masonry Units and Paving Interlocks," 28th CSCE annual conference, June 7-10, 2000, London, Ontario, Canada.)

form, the major proportion being in the size range of 2 to 3 mm with a total size range of 1 to 10 mm. The water content is adjusted to 12 percent during mixing and the pellets are air-cured for a minimum of three days before charging to the sinter plant, where they account for 3 percent of the total charge. The article also addressed the direct injection process currently on trial in Germany and the United Kingdom, where injection is used to pass fine dust into the liquid metal in the furnace. Fine dust is blended with hydrating dusts such as burnt lime and carbon. The metal oxide content of the material is about 70 percent and has a particle size range of 0 to 8 mm, making it ideal for direct injection into a range of furnaces.

Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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