Clinker viscosity

The content of clinker melt is increasing with temperature, and its viscosity is decreasing. The content of hqnid phase at chosen temperature (compare with Sect. 2.2) can be calculated from corresponding multicomponent systems. Lea and Parker [24] gave the simplified formnlae, which permit the content of liquid phase calculation ... 

Fig. 2.25 Iso-viscosity curves (Pa s) of clinker melt in relation to R O, MgO and SOj content (after [39]) the liquation field is grey...

Fluorine and chlorine up to 1 % have the strongest decreasing effect on the viscosity of clinker melt [41], but further increase of their content gives the qnick increase of viscosity as a result of crystallization of chnker phases. As the infrared spectra has shown they increase also the share of octahedral groups [MOJ. ... 

Fig. 2.65 Influence of some minor eomponents on viscosity of clinker melt (after [39]) cation ionic potential (z/r) (i), bond energy (2)...

The reaction of clinker phases with water, together with the crystalUzation of hydrates, brings about the substantial changes of rheological properties of the paste. The formation of hydrated phases and, according to Locher [28], the morphology of hydrates crystallized in the liquid phase or on the surface of cement grains, leads to the reduction of distance between them and the viscosity of paste is enhanced. At... 

To speed the sample encapsulation/impregnation step using a slide warmer or hot plate, the technique described by Chromy (1992a) is helpful. A sample cup, the bottom of which was covered with 1.0 to 2.0 mm-diameter clinkers or crushed clinker particles, was heated to approximately 80 C. Freshly mixed low-viscosity epoxy resin was poured over the clinker particles and allowed to harden, requiring from 5 to 10 minutes. The encapsulation was then sawn to expose the clinker sections or, better, the bottom side was ground with a coarse grit (180 to 320) to quickly expose the particles. 

Large to very large, idiomorphic alite crystals Correlated with increasing SO3 content in low-alkali laboratory clinkers reduced viscosity of melt strength loss (Dreizier, Strunge, and Knofel, 1985)... 

Increase in alite size and idiomorphism Lowered viscosity of melt resulting from increase in clinker sulfate and degree of sulfatization (sulfate to alkali ratio) (Strunge, Knofel, and Dreizier, 1985)... 

Quiokmount, a medium-viscosity resin mixed at 2 parts powder to 1 part liquid, by volume, for grain mounts and clinker encapsulations ... 

Calcium aluminate cement with a lower or intermediate AI2O3 content cannot be produced in rotary or shaft kilns of the type common in the manufacture of Portland clinker. The temperature range between incipient melting and complete fusion of the raw mixes is too narrow to permit successful clinkerization, in which a melt and solid phases must coexist. Moreover, the viscosity of calcium aluminate (-ferrite) melts is significantly lower than that of the calcium silicate-aluminate-ferrite melts formed when Portland clinker is produced. 

Since these two oxides both occur almost entirely in the liquid phase at clinkering temperature, this modulus characterizes the composition of that phase. If the ferric oxide content is higher, so that the iron modulus is lower, the viscosity of the melt decreases. For a value of IM < 0.638 the clinker phase called tricalciumaluminate (C3A) fails to form CjA-free cements are characterized by increased sulphate resistance. In industrial cements this modulus is generally between 1.3 and 4.0 and most often between 1.8 and 2.8. In special cements it may have much lower values (down to about 0.4). 

The Gladstone pipeline uses Wilson-Snyder positive displacement pumps. At the weight concentration of 60-64%, the slurry acted as a Bingham mixture, with non-Newtonian viscosity characteristics. However, it did feature clay, sand, and iron, as the materials were formulated for the manufacture of clinker cement. The pipeline operation speed was maintained at 2 m/s and the pressure drop was around 300 kPa/km. API 5LX steel with a high yield strength was used. Corrosion rates as high as 0.25 mm/year were measured during the initial phase of operation of the pipeline. 

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