CEE April-June 2012

Fig 1: XRD Pattern of Copper Slag 6 00 400 200 10 20 3 0 4 0 Although all the three materials viz., Iron Ore, Copper Slag & Flue Dust are chemically similar in terms of their iron content, they differ significantly in their phase composition, as given below: - - - - Iron Ore Copper Slag Flue Dust Hematite, Magnetite, Spinel, Quartz Iron Silicate, Fe3Si, Birnessite, Calcium aluminium Silicate, Amorphous phase {Glassy phase) Hematite, (Fe203), Cristobalite , Quartz (Si02), CaA4Fea0, 9 , Amorphous phase (Glassy phase), Carbon The f act that Copper slag shows Gain on Ignition instead of Loss on Ignition, suggests that at least some of the iron and silica are present in low valence state, which is corroborated by XRD analysis. On the other hand, Flue Dust shows the presence of Hematite (F 2 0 3 ) as the maj or form of iron and quartz & cristobalite as main silica bearing phase. The optical microscopic analysis under transmitted light in conjunction with XRD analysis shows approximately 25 % and 10% glass content respectively, for Copper slag and flue dust. The iron ore is somewhat different from these two industrial by-products in the sense it is nearly devoid of any amorphous phase and contains minor amounts of magnetite, quartz & spinel in addition to Hematite as Fig2: XRD Pattern of Flue Dust 1000 .. .. 0 .. 0 ! 0 ! ~ ! ~ " ~ # 0 600 " ll1L ~ 20 30 •o 50 60 80 4. 1.2 Burnability Studies: From the analysis it is apparent that both copper slag & flue dust have nearly the same iron content as that of iron ore and hence they are chemically suitabl e materials as a direct replacement to the iron ore. However, as they differ mineralogically, their compatibility with other major cement raw materials needs to be evaluated for their use in the manufacturing process. A burnability test was conducted on three raw mixes one containing conventional iron ore at 3%, and other two having either Copper slag or flue dust at 3% in place of iron ore. Fine tuning of raw mixes were done such that all the raw mixes are identical in terms of their moduli values as well as fineness. The results of the burnability tests are given in Table.3. In cement industry parlance, the quantity of uncombined lime or free lime is taken as an indicator of reactivity of the raw mix-lower the amount of free lime, better is the reactivity of the raw mix. The results show that both copper slag and flue dust possess equal or slightly superior reactivity as compared to iron ore and hence qualify for use in cement manufacture. The better reactivity may be attributed to their glass content and presence of ,--- ----- - ----- - ---- ----------. more reactive forms of silica # • • • SAMPLE DETAILS Kiln Feed with 3% Iron Ore Kiln Feed with 3% Copper Slag Kiln Feed with 3% Flue Dust the major phase. . : • FIRING TEMPERATURE °C % Free Lime at different firing Temp 1300°C 1350°C 1400°C 6.6 3.2 1.9 6.5 2.9 1.6 6.3 2.8 1.5 Percentage Free lime determined as per IS- 4032 and silicates. 4.2. Spent Pot liner (SPL) from Aluminium Industry & its Utilization: Samples of SPL and associated brick liner was collected from MALCO, and examined for use as AFR (Alternate Fuel & Raw material) in cement manufacture. The observations are given below. 7