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Customized Cement Additives to Deliver Maximum Benefit

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Customized Cement Additives to Deliver Maximum Benefit Customized Cement Additives to Deliver Maximum Benefit September 2011 Introduction Cement Additives Briefly Role in CO2 Reduction Facilitate Alternative Raw Materials & Fuels Traditional Influence of Additives Customised Approach 2 © 2011W. R. Grace & Co. Why Cement Additives? . Why use an additive? . Cement can be made without using chemical additives . They are not (usually) needed . So why do some plants use them? . How to discover a profitable way to exploit the application of a chemical additive? . Create economic value from the benefits that an additive can create that exceeds their cost . Requires knowledge of cement plant, cement, market requirements, costs, flexibilities/constraints, etc . Requires knowledge of cement additive capabilities, applications, formulations, costs, etc . Requires a rigorous evaluation procedure 3 © 2011W. R. Grace & Co. Cement Additives – Development Chemical compounds for use in the production of cement to increase the output and efficiency of the grinding process and improve the performance and quality of the finished cement, with the objective to reduce overall manufacturing costs. 1967 1970 1990 2003 2004 HEA2® amine TDA® Quality CBA® Quality ESE® non- SYNCHRO® acetate grinding Improver series Improvers chloride early chromium- aids patented introduced for developed and strength reducing blended cement patented enhancers additives introduced introduced 4 © 2011W. R. Grace & Co. Value of Cement Additives . Increase in cement mill output, with associated reduction in cement mill system kWh/tonne, reduction in mill run hours and reduction in cement grinding costs. Increase production capacity to meet sales volume. Improving cement flowability (reduce pack-set) to shorten loading/unloading operations and reduce distribution costs. Improve cement performance, to meet customer needs, satisfy Standards, meet/exceed competition and improve market position. Improve cement performance to allow clinker chemistry changes or to lower raw material/fuel costs from use of alternative materials. Improve cement performance to increase use of cementitious materials (i.e. non Portland cement clinker). Improve cement performance to use cementitious materials to reduce the clinker factor to lower compositional costs, to increase cement volume per unit of clinker, to reduce environmental impact (e.g. CO2). Improve cement performance to permit higher class of cement or new cement type or to meet new market needs. 5 © 2011W. R. Grace & Co. Cement Additives Role in CO2 Reduction Avg 0.7t of CO2 is produced/each tonne of cement produced Less Fuel Mill Output Less CO2 Less Clinker More Alternative Fuels Productivity & Cement volume/ More SCM’s tonne of clinker 6 Cement Additives Role in CO2 Reduction EU Emissions Trading Scheme • Clinker replacement in cement is an opportunity • Consider 5% increase in filler in the cement • e.g. slag, fly ash, pozzolan, limestone, etc • Will reduce 0.05 * 0.85t CO2/t cement = 0.0425t • For a 1mtpa cement plant = 42,500t CO2 • At CO2 value of $15/t = $0.638mm or $0.638/t cement • This is in addition to usual process cost reduction • CO2 value depends on level with reference to NAP and ability to sell/buy allocations 7 © 2011W. R. Grace & Co. Cement Additives Role in CO2 Reduction Example 1 - Good clinker/SCM cost differential Pozzolanic Cement Version 4.2 Reference Mill Power 2,100 kW Electricity 0.06 $/kWh None ESE Ancillaries 500 kW R&M 0.5 $/t Additive Cost/t 0 1500 Total 2,600 kW Clinker 20 $/t Dosage g/t 0 500 Clinker tonnes 750,000 SCM 6 $/t SCM % 25 30 CO2 0 $/t t/hr 60 66 Clinker CO2 Factor 862 kg/t kWh/t 43.3 39.4 kWh/t cost 2.60 2.36 R&M Cost/t 0.50 0.45 Composition cost/t 1 15.50 14.80 1 ® CO2 cost/t 0.00 0.00 Sum 18.60 17.62 Saving/t 0.98 Additive Cost/t 0.00 0.75 Net Saving/t 0.23 Annual Saving $ 248,377 % Return 31% Cement Volume 1 1,071,429 1,153,846 Increase 0 82,418 Good Differential cost 1 Assumes 5% gypsum Net Saving, $0.23/t 8 Cement Additives Role in CO2 Reduction Example 2 - Lower clinker/SCM cost differential Pozzolanic Cement Version 4.2 Reference Mill Power 2,100 kW Electricity 0.06 $/kWh None ESE Ancillaries 500 kW R&M 0.5 $/t Additive Cost/t 0 1500 Total 2,600 kW Clinker 15 $/t Dosage g/t 0 500 Clinker tonnes 750,000 SCM 10 $/t SCM % 25 30 CO2 0 $/t t/hr 60 66 Clinker CO2 Factor 862 kg/t kWh/t 43.3 39.4 kWh/t cost 2.60 2.36 R&M Cost/t 0.50 0.45 Composition cost/t 1 13.00 12.75 1 ® CO2 cost/t 0.00 0.00 Sum 16.10 15.57 Saving/t 0.53 Additive Cost/t 0.00 0.75 Net Saving/t -0.22 Annual Saving $ -233,766 % Return -29% Cement Volume 1 1,071,429 1,153,846 Increase 0 82,418 Lower Differential cost 1 Assumes 5% gypsum Net Cost, $0.22/t 9 Cement Additives Role in CO2 Reduction Example 3 - Low cost differential, CO2 included Pozzolanic Cement Version 4.2 Reference Mill Power 2,100 kW Electricity 0.05 $/kWh None ESE Ancillaries 500 kW R&M 0.5 $/t Additive Cost/t 0 1500 Total 2,600 kW Clinker 15 $/t Dosage g/t 0 500 Clinker tonnes 750,000 SCM 10 $/t SCM % 25 30 CO2 15 $/t t/hr 60 66 Clinker CO2 Factor 862 kg/t kWh/t 43.3 39.4 kWh/t cost 2.17 1.97 R&M Cost/t 0.50 0.45 Composition cost/t 1 13.00 12.75 1 ® CO2 cost/t 9.05 8.40 Sum 24.72 23.58 Saving/t 1.14 Additive Cost/t 0.00 0.75 Net Saving/t 0.39 Annual Saving $ 416,705 % Return 52% Cement Volume 1 1,071,429 1,153,846 Increase 0 82,418 Lower Differential cost 1 Assumes 5% gypsum CO2 Value Net Saving, $0.39/t 10 Utilizing Alternative Fuels and raw Materials Selection of alternative raw materials and fuels needs careful consideration of the potential impact on: Environmental Emissions Process Operation Cement Heath & Safety Cement Performance Overall Economics 11 © 2011W. R. Grace & Co. Effects on Cement Performance Limitations are often imposed on alternative material usage due to Environmental and/or Health and Safety reasons. However, the full impact on cement performance has not been studied for all trace elements and as noted by Taylor becomes complex in combinations of multiple trace elements in the same cement. However the role of many minor elements has been studied sufficiently to predict certain potential effects, for example concerning Setting Time Early Strength Late Strength 14 © 2011W. R. Grace & Co. An Alternative Solution What is needed is a solution to quality issues that does not simply require an increase in cement fineness and thus a loss in mill throughput, promotes maximum plant utilization and facilitates the use of available alternative fuels and materials. One clear alternative is the use of chemical additive technology in the finished grinding step. Many of the detrimental impacts on clinker mineralogy can be mitigated in the finished grinding phase through the application of chemical additives. 15 © 2011W. R. Grace & Co. An Alternative Solution For instance, cement additives known as Quality Improvers have been formulated to address specific quality issues and are in regular WW use. Early and Late Strength Enhancement – CBA, TDA, ESE… Extend Set Times – RDA… Shorten Set Times – TDA… Reduce Water Demand – TDA… Reduce Cr (IV) - Synchro 16 © 2011W. R. Grace & Co. Cement Additives – Capabilities Performance Additives Performance Processing Additives Processing Process Reduce coating and Reduce Packset Increase Mill Output, by 5 - 30% Narrower cement PSD (Grinding performance) Quality Increase 28-day strength, 5-15% or say 2 - 10 MPa Increase 2-day strength, 10-30% or say 2 - 10 MPa Reduce setting time, 10-40 minutes (initial set) Extend setting time, 10-40 minutes (initial set) Reduce water demand (concrete), by 2 - 5% 17 © 2011W. R. Grace & Co. Customised Additives One of the key modern challenges is to accommodate an increased use of supplementary materials and fuels. The demand for high-performance, versatile and robust additives (strengths enhancers, water reducers,…) is increasing year by year. Grace has developed a proprietary method to screen for additive components and optimize the formulation for a given, individual cement. The process involves: 1) modern statistical methods for multi-component screening and optimization; 2) improvements in the sampling and handling of cement samples and preparation of mortar specimens. 18 Why Customised Additives? Traditional Approach - understand needs for the additive Select “generic” additive able to influence cement performance in a common way In part dependent on cement type, but mostly on additive chemistry. Customisation aims to “match” the cement variables to the cement additive variables Huge number of permutations, needs screening and statistical approach. Requires numerous physical tests But still needs to be “robust” to be not so specific so that only suits a unique set of variable, i.e. cannot deal within source variability But test methods also involve standard deviation, so need to reduce the testing “noise” Result is higher performing additive Part from optimised dosage and combination of chemicals 19 Part from matching to cement characteristics © 2011W. R. Grace & Co. Variables and Variability There are many variables in a cement / additive system, which interact simultaneously: Cement chemistry and physical Additive chemical components are not differences influenced by materials and the same, do not have the same effect, process: and their availability and cost varies Silicates, LSF or C3S:C2S regionally: Aluminate, reactivity, alkali modified Glycols (~5) Ferrite, A:F ratio Alkanolamines (~10) Alkalis, Total and water soluble Na/Ca chlorides Huge Sulfate, Clinker and Cement Inorganic
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