页岩提钒尾渣基地聚合物一体化制备研究
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摘要
以页岩提钒尾渣为主要原料,采用与碱激发剂混合焙烧的方式提高其反应活性,然后加入偏高岭土校正硅铝比后制备成只需直接加水即可得到地聚合物的粉体胶凝材料,免去碱溶液激发过程,实现尾渣基地聚合物的一体化制备。采用正交实验考察碱激发剂用量、焙烧温度以及焙烧时间对地聚合物强度的影响。探究了偏高岭土掺量以及液固比对地聚合物强度的影响。结果表明,在碱激发剂用量为25%,焙烧温度550℃,焙烧时间1 h的条件下,得到的尾渣活性最高。在偏高岭土掺量为30%,液固比为0. 35时制得的地聚合物产品抗压强度最高,达到40. 41 MPa。尾渣经过与碱激发剂混合焙烧处理后,低活性石英消失,生成了多种可溶性硅铝酸盐,尾渣反应活性大幅提升。粉体胶凝材料加水后,活化尾渣及偏高岭土中的活性硅铝溶出而后发生聚合反应,形成无定形结构的地聚合物胶凝体,从而使最终产品具有较高的力学强度。
In order to beneficiate vanadium tailing into useful products,the vanadium tailing as the main feedstock to synthesize geopolymer. The reaction activity of vanadium tailing can be improved by roasting with alkali. After roasting,the metakaolin was added to modify the ratio of silicon to aluminum and the precursors of geopolymer was obtained. Water instead of alkali solution is used in the preparation of geopolymer. The effects of alkali dosage,roasting temperature and roasting time on the reaction activity of vanadium tailing were investigated by orthogonal experiments. The effects of different metakaolin content and ratios of water to binder were also studied. The results show that vanadium tailing are activated under the condition: alkali dosage is 25%,the roasting temperature is 550 ℃ and the roasting time is 1 h. The compressive strength of geopolymer is up to 40. 41 MPa,under condition of 30% metakaolin content and ratio of water to binder equal to 0. 35. After the vanadium tailing is treated by roasting with alkali,the slightly active quartz disappears and produces a variety of soluble aluminosilicate,the reaction activity of the tailings is greatly improved. After adding water,the geopolymeric precursor dissolves to form an alkaline environment,then activated silica and aluminum are dissolved and condensed in alkaline environment to form amorphous geopolymeric structure, endowing the final product with excellent mechanical properties.
In order to beneficiate vanadium tailing into useful products,the vanadium tailing as the main feedstock to synthesize geopolymer. The reaction activity of vanadium tailing can be improved by roasting with alkali. After roasting,the metakaolin was added to modify the ratio of silicon to aluminum and the precursors of geopolymer was obtained. Water instead of alkali solution is used in the preparation of geopolymer. The effects of alkali dosage,roasting temperature and roasting time on the reaction activity of vanadium tailing were investigated by orthogonal experiments. The effects of different metakaolin content and ratios of water to binder were also studied. The results show that vanadium tailing are activated under the condition: alkali dosage is 25%,the roasting temperature is 550 ℃ and the roasting time is 1 h. The compressive strength of geopolymer is up to 40. 41 MPa,under condition of 30% metakaolin content and ratio of water to binder equal to 0. 35. After the vanadium tailing is treated by roasting with alkali,the slightly active quartz disappears and produces a variety of soluble aluminosilicate,the reaction activity of the tailings is greatly improved. After adding water,the geopolymeric precursor dissolves to form an alkaline environment,then activated silica and aluminum are dissolved and condensed in alkaline environment to form amorphous geopolymeric structure, endowing the final product with excellent mechanical properties.
引文
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[2]Davidovits J.Geopolymers and geopolymeric materials[J].Journal of Thermal Analysis,1989,35(2):429-441.
[3]Duxson P,Provis J L,Lukey G C,et al.Understanding the relationship between geopolymer composition,microstructure and mechanical properties[J].Colloids and Surfaces A:Physicochemical and Engineering Aspects,2005,269(1):47-58.
[4]Zhang Z,Provis J L,Reid A,et al.Mechanical,thermal insulation,thermal resistance and acoustic absorption properties of geopolymer foam concrete[J].Cement and Concrete Composites,2015,62:97-105.
[5]Ati?C D,G9rür E B,Karahan O,et al.Very high strength(120 MPa)class F fly ash geopolymer mortar activated at different Na OH amount,heat curing temperature and heat curing duration[J].Construction and Building Materials.2015,96:673-678.
[6]Sarker P K,Mcbeath S.Fire endurance of steel reinforced fly ash geopolymer concrete elements[J].Construction&Building Materials,2015,90:91-98.
[7]Bakharev T.Resistance of geopolymer materials to acid attack[J].Cement and Concrete Research,2005,35(4):658-670.
[8]陈潇,王杰,朱国瑞,等.地聚合物力学性能主要调控因素的研究综述[J].硅酸盐通报,2017,36(9):2994-3002.
[9]Guo B,Pan D,Liu B,et al.Immobilization mechanism of Pb in fly ash-based geopolymer[J].Construction and Building Materials,2017,134:123-130.
[10]Huang X,Huang T,Li S,et al.Immobilization of chromite ore processing residue with alkali-activated blast furnace slag-based geopolymer[J].Ceramics International,2016,42(8):9538-9549.
[11]Zhang J,Provis J L,Feng D,et al.Geopolymers for immobilization of Cr6+,Cd2+,and Pb2+[J].Journal of Hazardous Materials,2008,157(2-3):587-598.
[12]焦向科,李涛,罗仙平,等.“直接加水”一体化方式合成地聚合物研究现状及展望[J].硅酸盐通报,2016,35(9):2872-2878.
[13]Tero L,Zahra A,Juho Y,et al.One-part alkali-activated materials:a review[J].Cement and Concrete Research,2018,103:21-34.
[14]Behzad N,Jay S,Faiz U A S.Synthesis of heat and ambient cured one-part geopolymer mixes with different grades of sodium silicate[J].Ceramics International,2015,41(4):5213-6140.
[15]Peng M,Wang Z,Shen S,et al.Alkali fusion of bentonite to synthesize one-part geopolymeric cements cured at elevated temperature by comparison with two-part ones[J].Construction and Building Materials,2017,130:103-112.
[16]Liew Y M,Heah C Y,Li L Y,et al.Formation of one-part-mixing geopolymers and geopolymer ceramics from geopolymer powder[J].Construction and Building Materials,2017,156:9-18.
[17]Phair J W,Smith J D,Deventer J S J V.Characteristics of aluminosilicate hydrogels related to commercial“Geopolymers”[J].Materials Letters,2003,57(28):4356-4367.
[18]Lee W K W,Deventer J S J V.Use of infrared spectroscopy to study geopolymerization of heterogeneous amorphous aluminosilicates[J].Langmuir,2003,19(21):8726-8734.
[19]Barbosa V F F,Mackenzie K J D,Thaumaturgo C.Synthesis and characterisation of materials based on inorganic polymers of alumina and silica:sodium polysialate polymers[J].International Journal of Inorganic Materials,2000,2(4):309-317.