Cement Energy and Environment

10 90 8 7 • N .. .. - ~---T---j· r -----r--- , I 1 l I -~---+---~--- 1 I • ~ c: ~ s ~ .. it 4 3 10 0 --- a s.;> 'M• 1:30H:SS •£3C:S•30 ~--- -,...,'II' • 1l6<7 C3S•S C:S•21 I --s.-19 o\1• 16991 C3$ • 5! C:S • 2: : ~16>~ •1&6l CS •l7 C:S•ll 0 600 1200 1800 2400 3000 3600 Size, [m1aons) Figure 1: Comparison of Bond test feed particle size distribution for clinkers from different work index categories To elucidate the effect of the particle size on work index for similar mineralogy further, one more set of comparison is given in figure 2. It shows the granulometry of some of the clinker samples as received for the test. Comparing the samples S-4, S-7 and S- 20 for example it is amply clear that the nodule size is one of the major factors influencing the clinker work index and need to be controlled carefully for avoiding increased energy consumption in cement mills. ,oo,====z~e;-~-~- :::--=-~--,- ~ ~ ~ -+-5-' .v ... ,, 'ee ClS•,., C2S · » -g a W W • l1!06C3S •U C2$ • U :::1 E - ......... 5-7W • 1HC2.ClS -•I.C2S • lQ i3 20- ___ _ _ _ _ --s.,, W· - 1l6H CJS -~i ca - .,e ~$-1! Wi • 1 ,,97 Cl$ •!!. C::S • 01~~------~~====~====~ 0 10 20 30 40 Size, [nvn) Figure 2: Comparison of clinker granulometry as received for bond test in the light of differential grindability S-19 Alite and belite sizes of all the clinkers examined in the present study lie in a considerably narrow range and hence there is not much effect of alite and belite sizes on the grindability of examined clinkers. However amongst various categories of clinkers considered, morphology of the clinker phases (in terms of their shape) is observed to be playing an important role in their Bond index. A Few photographs illustrating the differences in crystal shapes are given in Fig. A1 - A4. Based on the microscopic observations following effects are found to be prominent. • Clinkers having well defined Alite crystals & sharp edges are observed to be having higher Bond index values. The Bond index is observed to be increasing with number of faces in the alite crystal. Clinkers having elongated alite crystals (Lenticular characteristics) are observed to be having more work index. • Clinkers in which Belite crystals are formed in well-rounded shapes and having clear boundaries are observed to be having higher Bond index values. However, clinkers carrying belites with less apparent & hazy boundaries and having shapes deviating from roundish geometries are observed to be easier to grind. S-19 Figura A1: Photomicrographs of sample S-19 showing large multifaceted (i.e. hexagonal, pentagonal & tetragonal) & clearly defined sharp edged elite crystals (as seen in A. B). The Bond Index of the sample S-19 is found to be highest amongst examined clinkers at 16.99 KWh/T. 5