Kinetic Mechanism of Desilicated Fly Ash Lime Consumption

被引：0
作者：
Falayi, Thabo [1 ]
Okonta, Felix Ndubisi [1 ]
Ntuli, Freeman [2 ]
机构：
[1] Univ Johannesburg, Dept Civil Engn Sci, POB 524, ZA-2006 Johannesburg, South Africa
[2] Univ Johannesburg, Dept Chem Engn, POB 17011, ZA-2028 Johannesburg, South Africa
来源：
MATERIALS SCIENCE-MEDZIAGOTYRA | 2018年 / 24卷 / 02期
基金：
新加坡国家研究基金会;
关键词：
desilicated fly ash; modified Jander kinetics; toxicity; EXTRACTION;
D O I：
暂无
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
This paper presents study of the kinetic mechanism of lime consumption using desilicated fly ash (DFA). Desilicated fly ash (DFA) a residue from leaching of silica from fly ash was stabilised using lime at elevated temperatures. DFA and lime were mixed in different ratios at optimum moisture content and maximum dry density and then cured at 40 degrees C, 80 degrees C and 100 degrees C for 4 days. 80 degrees C was found to be the optimum curing temperature. The DFA: lime ratio of 70:30 was found to have an average UCS of 8.6 MPa. Lime consumption was found to follow modified Jander kinetics with activation energy of 16 kJ/mol and a reaction grade of 3 meaning that the reaction was controlled by diffusion of reactants through a dense layer of reaction products. The main hydration products were calcium silicate hydrate and tricalcium aluminate. Toxicity leaching tests showed a 79 % reduction in the leachability of trace and heavy metals. Therefore, DFA can successfully be stabilised using lime.
引用
收藏
页码：192 / 196
页数：5
相关论文
共 19 条
  • [1] Quantification of the degree of reaction of fly ash
    Ben Haha, M.
    De Weerdt, K.
    Lothenbach, B.
    [J]. CEMENT AND CONCRETE RESEARCH, 2010, 40 (11) : 1620 - 1629
  • [2] Biernacki JJ, 2001, ACI MATER J, V98, P340
  • [3] Cable M, 1998, J AM CERAM SOC, V81, P1083
  • [4] Chen C., 2001, J MATER SCI, V46, P590
  • [5] Synthesis, characterization of mesoporous silica materials from waste coal fly ash for the classical Mannich reaction
    Dhokte, Aashish O.
    Khillare, Santosh L.
    Lande, Machhindra K.
    Arbad, Balasaheb R.
    [J]. JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY, 2011, 17 (04) : 742 - 746
  • [6] Ge extraction from gasification fly ash
    Font, O
    Querol, X
    López-Soler, A
    Chimenos, JM
    Fernández, AI
    Burgos, S
    Pena, FG
    [J]. FUEL, 2005, 84 (11) : 1384 - 1392
  • [7] X-ray diffraction: a powerful tool to probe and understand the structure of nanocrystalline calcium silicate hydrates
    Grangeon, Sylvain
    Claret, Francis
    Linard, Yannick
    Chiaberge, Christophe
    [J]. ACTA CRYSTALLOGRAPHICA SECTION B-STRUCTURAL SCIENCE CRYSTAL ENGINEERING AND MATERIALS, 2013, 69 : 465 - 473
  • [8] Recovery of gallium from coal fly ash by a dual reactive extraction process
    Gutierrez, B
    Pazos, C
    Coca, J
    [J]. WASTE MANAGEMENT & RESEARCH, 1997, 15 (04) : 371 - 382
  • [9] Synthesis of MCM-41 from coal fly ash by a green approach: Influence of synthesis pH
    Hui, K. S.
    Chao, C. Y. H.
    [J]. JOURNAL OF HAZARDOUS MATERIALS, 2006, 137 (02) : 1135 - 1148
  • [10] Jumate E, 2012, J APPL ENG SCI, V2, P35
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