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2. Project Overview. Purpose: To investigate a potential new market avenue for CKD as a reuse material . . 3. . Research at Dalhousie University. . Dalhousie University Founded in 1818 in Halifax, Nova Scotia Atlantic Canada's leading research centre $115M annual R
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1. 1 Portland Cement Association
Manufacturing Technical Committee Meeting
May 19, 2008
2. 2 Project Overview Purpose: To investigate a potential new market avenue for CKD as a reuse material
3. 3 Research at Dalhousie University
4. 4 Task 1: Literature Review and Market Assessment Initial report completed in 2007
Broad overview of treatment methods for various types wastewater
Focused on use of lime for chemical precipitation of target contaminants
Market assessment found that most promising application is in mine effluent treatment
Lime neutralisation with quicklime most widely applied treatment method
Metal commodities in demand/prices high, WW volumes are large & environmental discharge concerns
5. 5 Proposed CKD Reuse Application
6. 6 Task 2: CKD Characterization Study CKD sampled from six different plants:
Lafarge Canada Inc: Brookfield, NS
Ash Grove Cement Company: Clancy, MT
St. Lawrence Cement: Juliette, QC
Lafarge North America: Alpena, MI
Cemex Inc: Xenia, OH
Cemex Inc: Knoxville, TN
Quicklime (CaO):
Laboratory grade
Commercial vendor
7. 7 Analysis of Major Oxides
8. 8
9. 9 Variation in base properties can depend on:
Raw material used in cement production process
Kiln type and performance (long wet/ long dry/ preheated kiln)
Gas velocities in kiln
Dust collection system (bag house, electrostatic)
Potential impact to reuse of CKD as chemical precipitant
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13. 13 Task 1: Literature Review & Market Assessment
Proposal for literature review submitted on application of S/S technology for treatment of mine tailings (CAC)
Results would parallel with objectives of this study in terms of assessing market potential for commercial applications
Task 2: CKD Characterization Study
Base properties: particle size & surface area
Slaking Experiments:
Temperature reactivity tests
Possible blending trials (CKD & commercial quicklime)
Summer 2008
14. 14 Task 3: Bench-Scale Chemical Conditioning Trials
Focus will be on CKD treatment applications for mine effluents
100% CKD vs Quicklime vs Blend Ratios
Experiments will start in Sept. 2008
15. 15 Portland Cement Association & Cement Association of Canada
Colin Dickson, CD, PEng:
Director Business Development, CAC
Richard Bohan, PE
Director Education and Technical Services, PCA
CKD suppliers
(Lafarge Canada Inc, Ash Grove Cement Company, St. Lawrence Cement, Lafarge North America, Cemex Inc)
Chris Petrie, EIT
Xstrata Zinc/Brunswick Mine, Bathurst, NB
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18. 18 Task 2: CKD Characterization Study
19. 19 CKD Oxide Comparison
20. 20 Previous Published Work Peethamparan et al., 2008
21. 21 Previous Published Work Todres et al., 1992
22. 22 SEM of CKD Samples
23. 23 Factors Affecting Slaking & Product Quality Surface area of CaO particles
Slaking temperature:
Ideal 210°F (99°C) vs Practice 160-180°F (71-82°C)
Lime to water ratio:
Maintain constant temperature
Agitation:
Maintains temperature and prevents drowning or unhydrated particles
Slaking Time:
Varies between 2 – 30 minutes
Water Temperature:
Solubility increases as temperature decreases
24. 24 Current CKD Reuse Applications