Litre Weight

November 25, 2017 | Author: Hazem Diab | Category: Sintering, Fracture, Industrial Processes, Applied And Interdisciplinary Physics, Nature
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1- If Liter wt .of clinker is 1200 ± 100 g/L then quality of clinker is said good What are the effects if Lt. Wt. is out side of above range? Liter Weight of clinker is firsthand information about clinker is under fired or over -2 fired. In under fired clinker free lime (CaOf) is more then cement will have higher Le chatelier’s and Autoclave expansion's which affect the strength and durability of cement. if clinker is Over fired then it is harder to grind. Which affect mill through put and KW/ton. In general each Kiln have different acceptable range of litre weights from 1000gms/lt to 1400gms/lt depending upon its raw mix design and type of process Liter weight is a measurement tool for burnability in older days. Checking of free -3 lime will give correct picture. Any how regarding the question asked, if the liter weight is below the range, the clinker is more likely to have high free lime, higher dust content and lower compressive strengths. If the liter weight is +1300, you get dense clinker with low porosity which affects the grinding process. As Mr.Varma said, the acceptable range will differ from plant to plant. The sieve size is also important. Some plants use .+6mm to -12mm fraction, others use +9mm to -12mm fraction As it is understood by every one that the Liter weight is nothing but the bulk density -4 i.e. the compactness of well burnt particles of raw meal turned in to clinker. For quick assessment of clinker quality from the process this physical parameter is extremely .useful. Lower the liter weight unburnt clinker and higher the number over burnt clinker .The number could be different for different size of the clinker There exists a corelationship (Y=mX + C) between litre weight and free lime for -5 different clinker size fractions. The corelationship (-ve) will be either week or strong .for different clinker size fractions Based on this suitable clinker size fraction can be evolved after carrying out proper study for each Kiln to decide which clinker size sieve should be used for liter weight .determination 6- LW is an indication for the following: a. Good /bad burning condition b. Flame strength c. LP statues d. Siliceous Raw mix design High clinker LW main an over burn clinker so:7a. Inefficient cooling to this kind of clinker b. Reverse reaction for C3S to C2S and CaO .c. Clinker minerals crystal will be large which will make it hard to grind d. Clinker porosity will be lower To maintain clinker liter weight we have to check following parameter. 8 a. Check the Raw Mix design .b. C3S, C2S, C3A AND C4AF PERCENTAGE c. MAINTAIN BURNING ZONE TEMPERATURE IN THE RANGE 0F 1100-1400. .d. KILN SPEED ALSO TO BE MONITOR TO KILN FEED e. MAINTAIN O2 AND CO PERCENTAGE IN KILN INLET Clinker with high and low liter weight tends to have less reactivity and affects the .compressive strength CLINKER GRINDABILITY The grindability of clinker depends on its chemistry and on the conditions it experiences in burning. Hard burning and high melt contents resulting from a low silica

ratio increase initial grindability since they result in a clinker with low porosity. However, after most of the aggregates of crystals have been broken, the fracture properties of the individual phases dominate the rate of increase in fineness. Hardness is less important than brittleness and, since 3CaOSi02 cracks more readily than 2CaOSi02 in a micro hardness measurement, it is considered that clinkers with a high lime saturation factor are ground more readily than those with a low lime saturation factor. The specific power consumption for grinding clinker increases when the amount of fine material increases. The production of fine grained or dusty clinker is avoided by ensuring that strong nodules of clinker are formed by agglomeration in the kiln. The requirement is met when 90-95 per cent of the void space is filled with liquid melt, which means that between 15 and 25 per cent by mass of the charge must be melted.^^ Two properties of the melt are decisive in determining the rate of agglomeration of the clinker and the strength of the resulting nodules, namely its surface tension and its viscosity. It has been observed that increasing content of SO3 in the feed results in a more dusty clinker, and this has been ascribed to the decrease in melt surface tension associated with increased K2SO4 levels. The grindability of a clinker is related to the packing density of the individual clinker mineral grains suspended in the clinker melt. Due to their elongated habit, alite crystals pack less densely than the belite crystals, resulting in a clinker which is easier to grind. The grindability of a clinker sample sintered to a density of 3000 kg/m"^ is determined by its fracture energy and the size of the micro cracks present.^"^ The number and size of the latter can be related to the cooling regime experienced by the clinker. The measured fracture energies using notched sintered prisms of clinker lie in the range 12 20Jm^. From measurements of the impression made in each clinker phase by a Vickers micro indenter, and the size of the cracks radiating from the indentation, values for a brittleness index have been calculated: 3CaOSi02, 4.7; 3CaOAl203, 2.9; 2CaOSi02 and 4CaO• AI2O3 • Fe203, 2.0. The particle size distribution produced when a material is ground becomes wider as the material becomes easier to grind. During the intergrinding of cement constituents of differing grindability, the particle size distribution of the material which is harder to grind becomes narrower, the easier the other component is to grind. Conversely, the particle size distribution of the material which is easier to grind becomes wider the harder the other component is to grind.^'^ The properties of cements with several main components are influenced to a critical extent by the particle size distributions of the components. In spite of the greater fineness required, slag cements do not normally have higher water demands than a Portland cement of the same standard strength. As a rule, interground limestone Portland cements of the same strength require less mixing water than Portland cement in spite of their greater fineness

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