Chrame containing refractories are a kind of traditional material for the lining of alkali recovery furnaces, but the formation of hexavalent chrome compounds will give rise to detrimental effect on environment and hu...Chrame containing refractories are a kind of traditional material for the lining of alkali recovery furnaces, but the formation of hexavalent chrome compounds will give rise to detrimental effect on environment and human＇s health. With the gradual awakening of people＇s comciousness about environment protection, it is urgent to prepare environmental-friendly materials for alkali recovery jurnaces with high quality and long life. In this paper, alumina-rich MgAl2O4 spinel （ AR90 ） was used to replace chromite. The physical properties of dried （110 ℃ for 24 h） or fired （1 300 ℃ for 3 h） AR90 and chromite were studied, respectively. The alkali vapor method was used to determine the alkali resistance of the two materials. The results show that： （1） after drying at 110 ℃ for 24 h, AR90 specimens show higher apparent porosity and slightly lower bulk density than chromite specimens; after firing at 1 300 ℃ for 3 h, AR90 has significantly higher apparent porosity as well as higher bulk density; （2） after the alkali attack, the AR90 specimens sintered at 1 300 ℃ exhibit smaller strength change and much higher compressive strength than the chromite specimens; meanwhile, the permeability degree of alkali salt in chromite specimens is more serious than that in AR90 specimens, which indicates that AR90 possesses better alkali resistance.展开更多
采用微型晶化釜,在投料硅铝比(n(SiO_2):n(Al_2O_2),简称SAR)为3～14,含氟、低水含量以及无钠/低钠的SiO_2-Al_2O_3-四乙基氟化铵-H2O体系中、近中性和晶化温度170℃条件下,考察了富铝β沸石的晶相生长规律。采用XRD,SEM,^(27)Al MAS NM...采用微型晶化釜,在投料硅铝比(n(SiO_2):n(Al_2O_2),简称SAR)为3～14,含氟、低水含量以及无钠/低钠的SiO_2-Al_2O_3-四乙基氟化铵-H2O体系中、近中性和晶化温度170℃条件下,考察了富铝β沸石的晶相生长规律。采用XRD,SEM,^(27)Al MAS NMR,XRF,BET等方法,分析了铝源、晶化时间、系统水含量(n(H_2O):n(Si+Al))、投料SAR、原料焙烧温度等因素对晶化过程的影响。实验结果表明,以焙烧后的无钠/低钠硅铝胶为铝源有利于抑制杂相生成,适宜的n(H_2O):n(Si+Al)为3.5左右,晶化时间为7 d以上;投料SAR在10以下时,随焙烧温度的升高,晶化活性提高,经过1 000℃以上高温焙烧,投料SAR最低为7时能达到较高晶化活性;投料SAR在10以上时,随焙烧温度的升高,晶化活性降低,当投料SAR为10～14、焙烧温度为600℃时,可获得纯相、高结晶度和SAR为15以下的富铝β沸石;沸石产品形貌多为团聚体,多数试样可辨初级晶粒大小多为微米级(0.5～2.0μm),个别试样多为纳米级(30～100 nm)。展开更多
为了得到烧结致密,抗水化性好的烧结白云石,以钢渣为烧结剂制备了烧结白云石熟料。研究了钢渣种类(富铁钢渣、富铝钢渣)及加入量(加入质量分数分别为0.5%、1%、1.5%、2.0%、2.5%)对白云石熟料烧结性能、抗水化性以及荷重软化温度的影响...为了得到烧结致密,抗水化性好的烧结白云石,以钢渣为烧结剂制备了烧结白云石熟料。研究了钢渣种类(富铁钢渣、富铝钢渣)及加入量(加入质量分数分别为0.5%、1%、1.5%、2.0%、2.5%)对白云石熟料烧结性能、抗水化性以及荷重软化温度的影响。结果表明:引入钢渣后白云石熟料烧后收缩率增大,显气孔率降低,体积密度显著增加,抗水化性明显提高;与无烧结剂的对比,添加钢渣2.0%( w )后其荷重软化开始温度 t 0.6 下降约50 ℃,但其溃裂温度 t 2.0 均在1 700 ℃以上。展开更多
文摘Chrame containing refractories are a kind of traditional material for the lining of alkali recovery furnaces, but the formation of hexavalent chrome compounds will give rise to detrimental effect on environment and human＇s health. With the gradual awakening of people＇s comciousness about environment protection, it is urgent to prepare environmental-friendly materials for alkali recovery jurnaces with high quality and long life. In this paper, alumina-rich MgAl2O4 spinel （ AR90 ） was used to replace chromite. The physical properties of dried （110 ℃ for 24 h） or fired （1 300 ℃ for 3 h） AR90 and chromite were studied, respectively. The alkali vapor method was used to determine the alkali resistance of the two materials. The results show that： （1） after drying at 110 ℃ for 24 h, AR90 specimens show higher apparent porosity and slightly lower bulk density than chromite specimens; after firing at 1 300 ℃ for 3 h, AR90 has significantly higher apparent porosity as well as higher bulk density; （2） after the alkali attack, the AR90 specimens sintered at 1 300 ℃ exhibit smaller strength change and much higher compressive strength than the chromite specimens; meanwhile, the permeability degree of alkali salt in chromite specimens is more serious than that in AR90 specimens, which indicates that AR90 possesses better alkali resistance.
文摘为了得到烧结致密,抗水化性好的烧结白云石,以钢渣为烧结剂制备了烧结白云石熟料。研究了钢渣种类(富铁钢渣、富铝钢渣)及加入量(加入质量分数分别为0.5%、1%、1.5%、2.0%、2.5%)对白云石熟料烧结性能、抗水化性以及荷重软化温度的影响。结果表明:引入钢渣后白云石熟料烧后收缩率增大,显气孔率降低,体积密度显著增加,抗水化性明显提高;与无烧结剂的对比,添加钢渣2.0%( w )后其荷重软化开始温度 t 0.6 下降约50 ℃,但其溃裂温度 t 2.0 均在1 700 ℃以上。
