Utilization of Al-/Fe-/Si- Ceramic Matrices for Cadmium - - PowerPoint PPT Presentation

Minhua Su, Lingjun Kong, Jinfeng Tang, Hongguo Zhang Yu Liu, Diyun Chen

Guangdong Provincial Key Laboratory of Radionuclides Pollution Control and Resources Linköping University – Guangzhou University Research Center on Urban Sustainable Development School of Environmental Science and Engineering Guangzhou University, Guangzhou, 510006, China

• Dr. Minhua Su, E-mail: mhsu@gzhu.edu.cn

Utilization of Al-/Fe-/Si- Ceramic Matrices for Cadmium Detoxification in Wastes

School of Environmental Science and Engineering Guangzhou University

Guangzhou University (GZU)

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Guangzhou University (GZU) Guangdong Province Guangzhou City Being to be High- level Comprehensive Website: http://english.gzhu.edu.cn/index.htm GZU has 27 schools and enjoys a comprehensive variety of disciplines including philosophy, law, education, literature, history, science, engineering, economics, administration and arts.

Main routes for entry of cadmium into the food chain and uptake by

• human. (Vromman, V., et al., 2008)

Kidney damage Skeleton deformation Lung cancer

 Since 1990s, Cd was classified as a group 1 carcinogen (Program 2014)

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Cadmium

Global production of refined cadmium, 1950-2000. (International Cadmium Association (ICdA), 2002) Trends in Cadmium Consumption from 2005 through 2010. (ICdA, 2013) Batteries Pigments Coating Stabilizer Alloys and solar cell

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Cadmium Production and Utilizations

20 tons of the cadmium discharged into Liujiang river(Guangxi, China) by a Mining plant, causing severe cadmium pollution affecting up to 4 million people. (Reported in January, 2012) A ¥ 40.7 billion project (began in 1979) to restore cadmium contaminated farmland in the Jinzu River basin, Japan. (Reported in March, 2012)

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Cadmium-Laden Sludge

Production/After used Water body Sediment/Sludge Discharged Transported Precipitated Incidentally/intentionally discharged! Difficult to remediate!

The need of additional stabilization due to the weak binding ability of sorbents by physical

• r chemical adsorption.

Cadmium bearing waste

Common Treatment of Cadmium Bearing Waste

Bauxite (Miller, B. B., et al., 2004) Kaolin (Yao, H., et al., 2005) Montmorillonite (MMT) and silica (Lee, M.-H., et al., 2005) Calcium oxide (Miller, B. B., et al., 2006) Alumina (Kuo, J.-H., et al., 2009) Cement based wastes forms (Polettini, A., et al., 2002)

 Solidification/stabilization (S/S) process Drawbacks:

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Techniques Ceramic Sintering Process (CSP) Environmentally Friendly Waste-to- Resources

Proposed Technology for Cadmium Stabilization

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Metal-containing wastes

Sintering

Ceramic products

• r

With high acidic resisting ability

• K. Shih, et al. E.S&T., 2005; Y. Tang, et al. E.S&T., 2012

Aluminum-rich materials Iron-rich materials

Thermally converting them into non-hazardous / less hazardous products.

Equilibrium Diagrams of Cd-Al-O and Cd-Fe-Mg-O Systems

Cd-Al-O system (Colin, 1968) Cd-Fe-Mg-O system (Bashkirov and Kornilova 1980)

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Gamma-Al2O3 Hematite SiO SiO2

Sample Preparation, Characterization and Evaluation

CdO Matrices Pellets Mixtures Fired pellets Powder SEM/TEM CPLT + ICP PXRD

Major characterization and analysis techniques

Microstructure

• bservation

Qualitative analysis

Rietveld refinement

Quantitative analysis Stabilization effect evaluation

Milled & Dried

Pelletized at ~250 Mpa

Stoichiometric ratios of Cd/Al and Cd/Fe. Sintering Ground

γ-Al2O3 CdO + γ-Al2O3 Cd-Al-O phase

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, , p ,

"R-pattern", R ,

• m

c m p

• m

Y Y R Y  



2 , , wp 2 ,

( ) "R-weight pattern", R ,

m

• m

c m wp m o m

w Y Y R w Y   

exp 2 ,

"R-expected", R ,

exp m o m

M P R w Y   



2 , , 2 exp

( ) "Goodness of fit", GOF, chi

wp m

• m

c m

R w Y Y GOF R M P     



• Quantification Quality Evaluation for QXRD analysis

Incorporation Efficiency Evaluation Leached Metals Normalization

wt.% of Aluminate or Ferrite MW of Aluminate or Ferrite TR(%) wt.% of Aluminate or Ferrite wt.% of CdO MW of Aluminate or Ferrite MW of CdO  

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CdO + α-Fe2O3 → CdFe2O4 (Spinel) CdO + 2γ-Al2O3 → CdAl4O7 (Monoclinic structure)

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Cadmium-hosting Product Phase Formation via Sintering withAl-/Fe- Ceramic Matrices

wt.% of Aluminate or Ferrite MW of Aluminate or Ferrite TR(%) wt.% of Aluminate or Ferrite wt.% of CdO MW of Aluminate or Ferrite MW of CdO   The transformation ratios (TR, %) for cadmium incorporation into CdAl4O7 monoclinic structure and CdFe2O4 spinel.

Transformation ratios

Incorporation Efficiency

+ 2+ (s) (eq) (eq) 2

CdO + 2H Cd + H O 

+ 2+ 3+ 4 7(s) (eq) (eq) (eq) 2

CdAl O + 14H Cd + 4Al + 7H O 

+ 2+ 3+ 2 4(s) (eq) (eq) (eq) 2

CdFe O + 8H Cd + 2Fe + 4H O 

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Al

/Cd molar ratio of 4.0

Fe

/Cd molar ratio of 2.0

Leachability of CdAl4O7 and CdFe2O4

Leached at constant pH 4.0.

CdO + α-Fe2O3 → CdFe2O4 (Spinel) CdO + 2γ-Al2O3 → CdAl4O7 (Monoclinic structure)

Formation of robust crystalline structures Detoxification of the hazardous wastes

The (a) soluble Cd and Al concentrations in the leachates of CdAl4O7 monoclinic structure and (b) the soluble Cd and Fe concentrations in the leachates of CdFe2O4 spinel.

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The [Al]/[Cd] molar ratios in CdAl4O7 leachates and [Fe]/[Cd] molar ratios in CdFe2O4 leachates.

Leaching Behavior of CdAl4O7 and CdFe2O4

am AlOH ↔ Al

3OH

• am FeOH ↔ Fe

3OH

• < 4.0

<< 2.0 At pH 4.0 [Al

] should be 6.3×10-2 M (1701 mg/L),

[Fe

] should be 1.05×10-5 M (0.59 mg/L),

Incongruent dissolution

Views of sintered CdO + silica fume and CdO + α-quartz samples with Cd/Si molar ratios (Г = 1.0, 2.0, and 3.0) at 950 °C for 3 h. Cadmium-hosting Product Phase Formation via Sintering with Si-rich Ceramic Matrices XRD patterns of sintered (a) CdO + silica fume and (b) CdO + a-quartz samples with various Cd/Si molar ratios (Cd/Si molar ratio = 1.0, 2.0, and 3.0) at 950 ºC for 3 h. CdO + SiO2 → CdSiO3 2CdO + SiO2 → Cd2SiO4 3CdO + SiO2 → Cd3SiO5

Efficiency of Cadmium Incorporation into Cadmium Silicates

With silica fume Cd/Si = 1.0 With quartz Cd/Si = 1.0 With silica fume Cd/Si = 2.0 With quartz Cd/Si = 2.0 With silica fume Cd/Si = 3.0 With quartz Cd/Si = 3.0

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Leachability of CdO, CdSiO3, Cd2SiO4 and Cd3SiO5

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Summary

A successful reduction of cadmium under acidic environments, identifying a promising and safe avenue for cadmium-laden sludge treatment.

Su et al., EP, 2018

CdO + α-Fe2O3 → CdFe2O4 (Spinel) CdO + 2γ-Al2O3 → CdAl4O7 (Monoclinic structure)

• 1. Su,

Su, M.H. M.H., Liao, C.Z., Chan, T.-S., Shih, K., Xiao, T.F., Chen, D.Y., Kong, L.J.; Song, G. Incorporation of Cadmium and Nickel into Ferrite Spinel Solid Solution: XRD and EXAFS

• Study. En

Envir vironmental nmental Science cience & Tec echnology hnology, 20 2018, 52, 775-782. 2.

• 2. Su,

Su, M.H., M.H., Liao, C.Z., Chuang, K.H., Wey, M.Y., Shih K.* Cadmium Stabilization Efficiency and Leachability by CdAl4O7Monoclinic Structure. En Envir vironmental nmental Science cience & Te Technology, 20 2015, 49, 14452-14459.

• 3. Su,

Su, M.H., M.H., Tang，J., Liao, C.Z., Kong, L.∗, Xiao, T., Shih, K., Song, G., Chen, D.∗, Zhang,

• H. Cadmium Stabilization via Silicates Formation: Efficiency, Reaction Routes and

Leaching Behavior of Products. En Envir vironmental nmental Pollution

• llution, 20

2018, 239, 571-578. Environmental Pollution, 2018, 239, 571-578. 4.

• 4. Su,

Su, M.H. M.H., Liao, C. Z. Lee, P.-H., Li, H.L., Shih K.* Formation and Leaching Behavior of Ferrite Spinel for Cadmium Stabilization. Chemical Chemical Engineering Engineering Science cience, 20 2017,158, 2017, 287-293. 5.

• 5. Su

Su M.H.*, M.H.*,Kong, L.-J. Shih, K. Stabilizing Cadmium into Aluminate and Ferrite Structures: Effectiveness and Leaching Behavior. Journal Journal

• f

Environmental ironmental Management, nagement, 20 2017, 187, 340-346.

Recent Publications

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Thanks！

School of Environmental Science and Engineering Guangzhou University

• Prof. H.G. Zhang
• Dr. L.J. Kong