Products Prerequisites Composition N: Complete Guide & Downl

The composition of the cement is the foundation of the cement industry: the proportions of the limestone, the clay and the corrective materials, the chemistry of the raw mix and the oxide targets of the clinker decide the quality of the cement before the kiln ever fires: this article is the complete technical guide to the prerequisites and the composition of the cement products: the raw materials, the mixing, the modules and the clinker phases, in the honest and practical voice of the industry.

The Complete Cement Technical Package (931 files including the courses, the books, the Excel tools and the presentations: $249.99 one-time: instant download via the PayPal payment) includes the Products.Prerequisites.Composition module (dated March 2002, series N3) among its training material: the module teaches the composition of the cement products from the ground up: the raw materials, their chemistry, the preparation, the modules, the calculation of the mix and the composition of the clinker: this article walks the same path, so the reader of the module and the reader of this page meet at every checkpoint.

Why the composition deserves the study: the cement is not made in the kiln only: it is made in the quarry, in the raw mill and in the mix design: the chemistry of the feed is the destiny of the clinker: two plants with identical kilns produce different cements if their raw compositions differ, and the same kiln produces different strengths if the feed modules drift: the composition is the prerequisite of the process: the module title says it all, and this article explains all of it in order.

1. The Raw Materials of the Cement Production

The cement raw materials supply four analytical components: the lime, the silica, the alumina and the iron: the module opens with the natural materials that carry them:

• The limestone: the main carrier of the calcium carbonate: the calcareous raw materials cover 75 to 85 percent of the raw mix by weight: the limestone layers of the quarry hold 95 to 99 percent of CaCO3, while the chalk and the marl are softer and carry the clay minerals by birth: the module teaches the selection of the quarry layers using the analysis of the boreholes;
• The clay and the marl: the siliceous and the alumina carriers: the clays of the appropriate deposits provide the SiO2 and the Al2O3 with some iron: the clay content of the quarries varies, and the marls are the intermediate natural mixes of the lime and the clay: the module covers the correction materials: the sand for the silica, the iron ore for the Fe2O3, the bauxite for the alumina;
• The chemical composition of the typical mix: the finished raw meal of the dry process runs approximately 42 to 46 percent CaO, 12 to 15 percent SiO2, 3 to 5 percent Al2O3 and 1.5 to 3.5 percent Fe2O3, with the remainder the MgO, the alkalis, the sulfate and the moisture: the module gives the analytical table of the raw materials of the typical plant;
• The minor components: the alkalis (Na2O, K2O), the chlorides and the sulfur behave as the volatile cycles in the kiln: the raw material selection must respect the limits of the process: the module teaches the “alkali balance” of the raw mix because the volatile load is a prerequisite of the stable kiln operation;

The first prerequisite of the composition is a raw material deposit that satisfies both the quantity and the chemistry: the module opens with the quarry, the borehole campaign, the exploration sampling and the stockpile management: the cement plant is a chemistry factory that starts in the mountain: the composition decides everything downstream.

2. The Preparation of the Raw Mix: The Sequence of the Quarry to the Mill

Between the quarry and the kiln, the raw materials are crushed, proportioned, ground and blended: the module covers the preparation route as the second prerequisite:

• The crushing: the limestone and the clay are reduced to the feed size of the raw mill, typically 80 percent below 25 to 80 millimetres depending on the mill system: the crusher types and their selection are covered: the jaw, the impact and the roller crushers of the industry;
• The proportioning: the raw materials are extracted from the storage and fed in the correct ratio by the weigh feeders: the proportioning of the typical dry plant sends the limestone, the clay, the iron and the sand each at its setpoint in tonnes per hour: the module teaches the proportioning loops, the calibration and the fallback of the abandoned feeder;
• The grinding and the drying: the raw mill grinds the mix to the fineness of 12 to 15 percent residue on the 90 micron sieve and dries it with the kiln gas to below 1 percent moisture: the vertical roller mill of the modern plant is the standard: the module covers the mill, the separator and the fineness targets;
• The homogenization: the raw meal is blended in the homogenizing silos: the air-quenching systems, the continuous blending of the silo and the achieved homogeneity, measured by the standard deviation of the CaCO3: the typical raw meal blending standard deviation is below 1 percent for the good homogenization: the module teaches the operation of the silo;

The preparation route ends at the meal silo with a fine dry homogenous powder whose chemistry must be kept inside the narrow band: the “prerequisites” of the module title: the composition control begins at the quarry and ends at the preheater: the module takes the reader through each station with the instruments and the targets.

3. The Calculation of the Raw Mix: The Modules of the Composition

The heart of the composition discipline is the calculation of the modules: three dimensionless numbers define the chemical character of the mix and of the clinker:

• The lime saturation factor (LSF): the ratio of the CaO to the lime needed by the silica, the alumina and the iron for the full saturation: the typical LSF of the Portland clinker runs 90 to 102, with the operational target near 95 to 100: the LSF is the “lime load” of the mix: too high: the hard burning and the free lime; too low: the insufficient alite and the weak strength;
• The silica ratio (SR): the ratio SiO2/(Al2O3 + Fe2O3), normally 2.0 to 3.0: the higher the SR, the more the silica and the harder the burning; the lower the SR, the more the liquid phase and the easier the sintering: the module: there are operating windows per plant: the SR is the fluidizer of the kiln;
• The alumina ratio (AR): the ratio Al2O3/Fe2O3, typical 1.3 to 2.5: the AR controls the composition of the liquid phase and the ferrite-aluminate balance: the AR relates the sulfate resistance and the casting of the clinker;
• The calculation of the mix: the modules convert into the mix: the raw material analyses, the desired modules and the LOI (loss on ignition) of the materials: the module gives the classic calculation of the three-component and the four-component matrix: the Excel tool of the package does the same in the official spreadsheet: the engineer enters the analysis and the target, and the tool returns the ingredient proportions;

The modules are the language of the raw mix between the laboratory and the kiln: the module teaches the change of one module today and the response of the kiln tomorrow: the process engineer manipulating the modules understands why the mix changed and which department asked for the change: the composition is the conversation of the whole plant in three numbers.

4. The Composition of the Clinker and the Phases

Inside the kiln, the raw mix becomes the clinker, and the module leads into the composition of the burned product:

• The clinker oxide analysis: the typical clinker holds 62 to 67 percent CaO, 20 to 24 percent SiO2, 4 to 6 percent Al2O3 and 2.5 to 4.5 percent Fe2O3, with the MgO below 5 and the SO3 below 2: the module compares the raw meal and the clinker analyses: the LOI is gone and the ash of the fuel enters the composition;
• The Bogue calculation: the norm of the industry converts the oxide analysis into the phase composition: the alite (C3S), the belite (C2S), the aluminate (C3A) and the ferrite (C4AF): the Bogue equations: the module executes the Bogue step by step on a real analysis: C3S the result of the three modules:
• The microscopic composition: the actual minerals of the clinker with the polished sections: the alite crystals, the belite, the interstitial phases: the microscopic analysis confirms the burning quality of the clinker: the free lime (CaO) 0.5-2 percent in the well-burned clinker: the microscopy of the module in the laboratory part;
• The variability of the composition: the quality control of the clinker: the daily analysis and the shifts: the standard deviation of the clinker composition the limit of the cement quality: the module: the XRF based quality control and the kiln control loops;

The clinker is the intermediate product of the cement world, and its composition is the jury of the raw mix: the module lets the reader compare the designed mix modules with the actual clinker phases: when the two diverge, the process engineer knows whether the quarry, the mill or the kiln caused the drift: this ability is the “composition competence” the module gives.

5. The Cement Products and their Composition: From the Clinker to the Specific-Type

The cement product is the clinker plus the gypsum plus the options: the module of the products covers the range of the cement types and the composition rules of each:

• The ordinary Portland cement (CEM I): the clinker 95-100%, the gypsum 3-5%, no significant additional constituents: the composition normative of the EN 197 and the local standards; the CEM I 42.5, 52.5 in the strength classes;
• The Portland-limestone cement (CEM II/A-LL): the clinker 80-94%, the ground limestone 6-20%: the filler reacts partly: the composition control of the limestone purity (CaCO3 75%) per the norm: the module: the LL and the L varieties: the durability views;
• The Portland-fly ash and the slag cements (CEM II-B, CEM III): the SCM (fly ash 20-35%, the slag reduces up to 35-95 percent in the CEM III): the compositions and the processes: the module: the interactions of the supplementary materials and the hydration: the application of the presentations of the aggregates:
• The special cements: the white cement (the low iron: the Fe2O3 below 0.3%), the sulfate-resisting (the C3A below 3.5%), the low heat, the oil-well: each has its own composition window: the module lists the compositions and the standards for the engineer of the special-application plant and the labs:

With these the reader learns: the cement is a composition made to the order: the customer buys the strength class and the standard, and the plant makes the composition that satisfies the property: the cement product respect the composition limits of the norm, and the module is the practical score card of that composition.

6. The Quality Control of the Composition: The Laboratory in the Loop

No composition discipline works without the laboratory, and the module trains the quality control of the raw mix and the clinker:

• The analytical methods: the X-ray fluorescence (XRF) of the raw materials and the clinker, the wet-chemistry check, the loss on ignition and the sulfate titration: the module: the sample of the points, the frequency and the calibration of the XRF from the standards;
• The raw mix control loop: the hourly XRF of the raw meal, the calculation of the modules, and the adjustment of the proportioner setpoints: the automation of the loop: the module: the target ranges of the plant: LSF 96-100, SR 2.2-2.6, AR 1.4-1.8 as the example limits and the response time of the loop (from the change of the chemistry in the quarry to the change of the feeders);
• The clinker and the cement testing: the daily clinker analysis, the fineness and the setting of the cement, the mortar strength of the 28 days: the composition – the strength correlation: the module: reading the quality report of the plant like the engineer of the quality: the statistical process control charts:
• The operators of the laboratory: the shift in the lab, the preparation of the S8, the repeatability of the measurements: The module: the practice of the QA/QC: the registrations, the traceability, ISO 9001 and the ISO 14000 of the cement industry:

The laboratory is not behind the process, it is the pacemaker: the module closes the technical body:

7. The Special Topics: The Moisture, the Storage and the Feed Variability

The composition discipline has its enemies: the module lists them honestly:

• The moisture of the raw materials: the fluctuating % of the water changes the proportion of the dry basis: the module teaches the “dry basis” arithmetic, without the error: for the correcting dosing the moisture of each material must be continuously known:
• The stockpile blending: the sand, the clay, the iron are stored in the separate bay: the blending of the stockpile with the reclaim task: the module teaches the “making the quarry’s variation average out” mine: the composition in the layers: the module: the stacking and the reclaiming of the cap in the modern plant;
• The raw material changes: the seasonal quarry faces: the opening of new layers: the mix-design gets the “new recipe” and the process engineer recalculates: the procedures of the module of the “change management” of the raw materials: without the raw material change protocol, the plant burns the wrong mix as long as the sensors catch the drift:

The composition discipline therefore includes the logistics of the chemistry: the module arranges the composition as a system of the information: the sampling, the weighing, the blending, the correction: the “prerequisites of the composition” is the administrative planning of the raw material chemistry across the week: the lecture of the module.

8. The Frequently Asked Questions

What is the optimal LSF of the raw mix for the Portland cement clinker?

The operational target of the LSF usually lies between 95 and 100, and 90 to 110 covers the range of the industrial recipes: above the 100 the clinker becomes hard to burn and the free lime stays high, below the 90 the cement loses the strength and the C3S: the optimum belongs to each plant and its coal ash, but the band above the standard is a good starting point.

Why does the proportioning matter so much if the kiln is well-operated?

The kiln can correct the small drifts but not the systematic: the modules of the raw mix decide the phase composition of the clinker and the kinetics in the burning: A chemist-line of the guaranteed value: the kiln-scale proper burning: the kiln cannot fix the raw mixing: the mix is burned exactly: the proportioning (not only the kiln control) makes the cement.

What is the difference between the SR and the AR modules?

The SR (silica ratio) compares the SiO2 to the sum of the Al2O3 and the Fe2O3: it describes the share of the silicates vs the melt. The AR (alumina ratio) compares the Al2O3 with the Fe2O3: it fixes the composition of the ferrite and the liquid phase: the SR raises the difficulty of burning: the AR raises the SO3 resistance: both are the adjusting of the process.

Do all the plants use the same raw mix recipe?

No: the recipe is specific by the deposit: the quarries in the different: the modules and the raw mix representation: the components (clay, marl, iron, sand) always the same family but the percentage carries: the module area: the standard: the recipes of the plant are the same calculations: they are included in the modules of the course:

What is the “Bogue calculation”?

It is the indirect/standard calculation of the clinker phases from the oxide analysis: the C3S, C2S, C3A, C4AF: computed via the Bogue equations: the actual phase composition of the kiln is always modified by the sole and the burning, but the Bogue still is the accepted compositional description of the clinker used by all the ports:

The raw composition influences the cement color, or?

It does: the iron and the percentage of the ferrite determine the darkness of the gray: the white cement limits the Fe2O3 below 0.3 percent at the raw and of the fuel: the higher the ferrite the darker the cement, and the color switches from the pale to the dark gray as the compositions: to the same module: the engineer reads the shift in the composition by the last bag of white:

9. Conclusion

The composition of the cement products: the line that starts in the quarry and ends in the norm: the raw sides, LSF, SR and the AR, the raw mix, the preparation, the clinker phases and the cement types: the module Products.Prerequisites.Composition of the Complete Cement Technical Package (931 files: courses, books, excel and the presentations, $249.99 one-time with the PayPal) shows the discipline: this article has gone through the whole chain: the reader closes the reader with the ability to discuss the raw mix with the process and the quality of the cement plant: the composition is the prerequisite, and the prerequisite: the knowledge.

The original module of March 2002 is part of the well-structured course of the cement products of the package: the modules of the composition, the hydration, and the physics of the products: the reader: with the module and this article: the full understanding: the raw material in front of you and the cement behind it: for the engineer, the next step is the same: the open of the package, the material of the course, and the use of the full set of the 931 files of the industry: the button: that decision: the click of the PayPal, the download, and the plant’s improvement to the composition: the first lesson.

The Composition: From the Raw Mix to the Product Specification

The composition of the cement product stands on the composition decisions of the whole chain:

• The raw mix prerequisites: the lime standard of the kiln feed, the silica modules, the alumina ratios: the raw mix composition determines the clinker composition that determines the cement composition: the chain of the prerequisites;
• The clinker mineralogy: the alite and the belite, the aluminate and the ferrite: the phase balance of the clinker and the indexes (LSF, SM, AM): the nitrate of the clinker composition to the cement;
• The finish mill blend: the clinker, the gypsum, the additions: the SO3 specification, the fineness targets, the composition percent of the combined materials: the recipe changes of the product;
• The standard requirements: the composition limits of the regional and international standards: the max/%of the additions, the chloride and alkali limits, the declared composition of the CEM classes: the product as the legal promise;

The composition chapter closes the loop: every requirement of the product (the class, the strength, the durability behavior) takes its origin in the composition decisions taken two stages earlier at the quarry and the raw mill: the file positions the composition as the output of the whole process: the prerequisites of the earlier lines are the composition of the later products: the product that is a controlled chain.

Conclusion: The Prerequisites as the Product DNA

A composition is the result of every decision of the plant: the file concludes the N3 by summarizing the prerequisites that the products build:

• The raw mix defines the chemistry of the clinker: the lime, the silica, the modules;
• The burning defines the mineralogy of the phases: the degree of the formation, the free lime below the threshold;
• The grinding defines the fineness and the particle distribution of the cement: the strength development and the water demand;
• The addition and the quality of the gypsum defines the setting and the sulfate balance;
• The quality system then defines the product: the test, the release, the record: the steps from the mine to the market;

The engineer of the file understands cement as the product of the controlled chain rather than a single formula: the file gives the tools to check the raw mix, the kiln, the mill and the lab as one system and to intervene where the deviation enters. The byeproducts of the cement (the dust, the clinker, the mill rejects) are the return loop: the composition and the quality of the product are the fertile output of the chain.

The Prerequisites Audit: A Ten-Point Checklist

The file ends with the audit list the plant can run quarterly on the prerequisites:

1. The raw mix formula reviewed against the clinker targets (LSF, SM, AM) of the last 30 days;
2. The quarry feeding variability tracked (the standard deviation of the CaCO3 at the crusher);
3. The raw mill fineness and the homogeneity of the kiln feed held in the window;
4. The clinker free lime and the C3S content within the limits;
5. The gypsum quality control (the SO3 content, the form, the moisture);
6. The additions and the blends correctly proportioned at the finish mill;
7. The mill temperatures and the ventilation at the standard, the sulfate protected;
8. The fineness and the Blaine within the specification at the silo;
9. The setting and the strength tests on the daily samples matched with the targets;
10. The nonconformities closed with the corrective actions within the month;

Running the ten-point audit connects the plant floor with the specification sheet: each point answers one prerequisite and the composition product: the plant that audits its prerequisites can keep the product class with the margin: the file brings the composition as the transparent result of the controlled prerequisites.

The Composition Workbook: Three Worked Examples

The file treats the composition as a working subject: here the three examples the readers practice:

Case	Given	Computed	What the result controls
1. Raw mix for 62% LSF	Limestone 78% CaCO3, Marl 54% CaCO3	Mix 81/19 by the lime mass balance	The clinker potential C3S above 58%
2. Gypsum to final cement	Clinker SO3 0.4%, gypsum SO3 46%, target 2.8%	5.2% gypsum on finish	Setting regulated, 28-d strength window
3. Addition substitution	Slag 35% substitution, target Blaine	Grind adjusted +40 m2/kg, SO3 +0.3%	Workability and early strength

Carrying the three computations through the train of the file teaches the effect of every change: the raw rock to the kiln to the cement: the files of the cement industry are the arithmetic of the phases:

The composition control is then the counting of every kilogram: each percentage of the modules on the raw side translates to a percentage of the phases in the clinker, and from the clinker to the fineness and the strength of the product the next month: the chain that the file explains is completely accountable: the composition of the cement is not luck; it is the sum of the measurements and the arithmetic the engineers of the plant perform every day: the workbook of the file, with its tables and the practice examples, is written to be used at the desk, not only read in the office.

The kit of the quality manager in the same pages: the sampling points, the frequency of the composition checks, the index cards of the feed: the application of the workbook links the products chapter to the rest of the package courses: the engineer places the cement into the total material balance of the plant: takes what the milling puts out and the kiln feeds, and returns exactly the specification required: the loop is closed with the numbers that appear in the standard certificates delivered to the customers: quality as the numbers of the workbook.

This last point deserves the attention of the plant: the composition certificate the customer receives is a honest summary of the process control that preceded it. When the silo shipment is certified CEM II/B-M 32.5 N, the certificate is the evidence that the raw mix, the burning, the grinding and the blending of the last production days stayed inside the window: every certificate is a process audit in miniature: the quality manager who keeps the prerequisite variables (the clinker, the gypsum, the fineness) inside the established corridors can certify the composition with the confidence, and the deviations of the chemical modules today are the strength complaints tomorrow: the workbook explains that the product composition is the best instrument the plant has to look back at its own process: the certified cement is the mirror of the controlled plant: that is the idea the composition chapter of the N3 carries into the daily work of the factory.

This file is part of the Complete Cement Technical Package (931 files) available from cementequipment.org. Respective rights holders; library copy for the licensed single user.