Lime saturation factor

Raw Material Proportions. The three main considerations in proportioning raw materials for cement clinker are the potential compound composition the percentage of Hquid phase at clinkering temperatures and the bumabiUty of the raw mix, ie, the relative ease, in terms of temperature, time, and fuel requirements, of combining the oxides into good quaUty clinker. The ratios of the oxides are related to clinker composition and bumabiUty. For example, as the CaO content of the mix is increased, more C S can be formed, but certain limits cannot be exceeded under normal burning conditions. The lime saturation factor (LSF) is a measure of the amount of CaO that can be combined (20) ... 

AR = alumina ratio (alumina modulus). ASR = alkali silica reaction. LSF = lime saturation factor. SR = silica ratio (silica modulus). C, = analytical (total) concentration of x, irrespective of species, [x] = concentration of species x. x = activity of species x. RH = relative humidity. =... 

Lime saturation factor, silica ratio and alumina ratio... 

Lime saturation factor (LSF) = Ca0/(2.8Si02 -f I.2AI2O3 -f 0.65Fe2Oj)... 

The quantity of lime added is always, therefore, kept below the calculated limit (the so-called lime saturation factor, LSF = CaO/CaOmax)-... 

Tables 31.20, 31.21, and 31.22 provide the chemical analyses of raw meal feed, clinker, and petroleum coke. Based on that are the calculations of the lime saturation factor, silica ratio and alumina ratio of raw meal, and clinker.

Although one must be aware of the potential problems posed by particle size effects in slurry and powder analysis, in many cases, the range of particle size and particle composition for a process stream is sufficiently constant that reliable measurements can be made using on-line XRF systems. Successful applications which have been reported include an on-stream XRF measuring system for ore slurry analysis [38] a system for direct XRF analysis of pulverised coal streams [39] and on-stream analysis of cement using XRF [2, 40]. The latter is available as a commercial on-stream cement analyser which it is claimed can measure lime saturation factors (a function of Ca, Si, A1 and Fe concentrations) with a relative standard deviation of better than 1% in 100 s measurement time. Obtaining such results with a sampHng frequency of over 10 measurements per hour can allow effi-... 

From the data given in Table 3.5 it can be concluded also that the heat of hardening can be lowered by the CjA and CjS content decrease in the latter case it means the reduction of the lime saturation factor. Unfortunately, this is simultaneously linked with the lowered strength development and reduced class of cement. 

As it can be concluded from the information relating to the chemical mechanism of cement paste corrosion under sea water, its resistance depends primarily on the Ca(OH)2 and calcium aluminates content it means that the resistance increases with the C-S-H phase content in the paste. Therefore cements poor in C3A, with low C3S/C2S ratio, that is those with high sihca ratio and low lime saturation factor show the best resistance. Cements with high slag and pozzolana content are extremely resistant, particularly when they are produced from clinker poor in C3A. Very good results were assured by the three component cements, with 30% pozzolana addition, beside of slag [98]. Calcium aluminate cement reveals, as in the case of sulphate attack, the highest corrosion resistance in marine environment (see Chap. 9). 

As it is known, that the heat consiunption of the clinkering process is mainly due to the calcium carbonate decomposition and the long period (about 20 min) of clinker heating in sintering zone at maximirm temperamre, to assirre full alite formation. Therefore the energy consirmption increases with lime saturation factor (see Chap. 2). 

Fig. 9.31 Effect of cooling rate on the strength of cements with various lime saturation factor, (according to [141])...

Stalk et al. [141-143] studied the possibility of belite cement activity improvement by qnenehing. A great impact of the cooling rate on the strength of mortar was proved, of elinker lime saturation factor below 90% (Fig. 9.31). 

Inorease in alite content and orystal size, increasing difficulty in burning, reduction in cement strength Relative increase in lime saturation factor (Long, 1982b)... 

Coarsely crystalline alite surrounded by finer-grained alite and free lime Coarse quartz and locally high lime saturation factor converting previous beiite nest to alite (Miller, 1980)... 

Equal alite and belite Lime saturation factor=approximately 88% (Fundal, 1980)... 

Large patches of belite belite nests from coarse quartz Selective reaction of raw mix components clay at lower temperature than that for quartz, muscovite, hornblende, and Ca-feldspars resulting in early nodulation (micronodules) and clinker dust with high lime saturation factor (Fundal, 1980)... 

Free lime as primary phase belite only as inclusions in ante High lime saturation factor (Long, 1982a)... 

To use the F. L. Smidth burnability equation, a lime saturation factor (LSF) of not greater than 100% or less than 88% is stipulated. If the LSF is greater than 100%, the free lime calculated by the Bogue equation must be added, and calculated as follows ... 

In high-CjS (high alite) Portland cements the amount of ahte in the clinker is increased at the expense of belite. Usually such chnkers also contain moderately increased amounts of tricalcium aluminate. In the production of high-CjS clinkers the lime saturation factor of the raw meal is increased to values close to or even moderately exceeding LSF=100. 

Some Portland cements may contain elevated amounts of belite (C2S), at the expertse of alite (C3S). To produce such clinkers, the lime satiuntion factor of the raw meal must be reduced, typically to values between about LSF=80 and LSF=90, instead of the LSF>90 that exists in ordirrary Portland cement. (Cements made from clinkers with even lower lime saturation factors, which contain no or only very limited amounts of ahte, are called belite cements, and are discussed in section 3.2.)... 

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