摘要
拜耳法赤泥是用氢氧化钠溶解铝土矿生产氧化铝过程中产生的固体废弃物。针对拜耳法赤泥的强碱性、重金属含量高等特点,提出了一种利用酸性氟化钙污泥进行共同烧制砖块的方法。以砖块的氟离子浸出量、铬离子浸出量、抗压强度、砖块密度及烧失量5个变量为评价指标,利用主成分分析法对五个指标进行综合评分,并研究了以氟化钙污泥与赤泥比,黏土添加量、铝灰添加量、黏结剂添加量、烧结温度为自变量对综合评分的影响。利用响应面法(RSM)对实验数据进行分析,得出最佳实验条件依次为氟化钙污泥与赤泥比=61.1%,黏土添加量=21.4%,铝灰添加量=15%,黏结剂添加量=2.5%,烧结温度=1 000℃。此条件下所得砖块对应的氟离子浸出量为0.33 mg·L^(-1),铬离子浸出0.034 mg·L^(-1),抗压强度5.73 MPa,烧失量9%,砖块密度1.07 g·cm^(-3)。可用做非承重砖。
The Bayer red mud is a solid waste generated in the alumina production process by the sodium hydroxide dissolving bauxite method. Using Bayer red mud and acidic calcium fluoride sludge to make co-fired bricks was proposed in this study to eliminate the Bayer red mud with high alkalinity and heavy metal content.Five variables（ amount of fluoride ion leaching,amount of chromium ion leaching,compression strength,ignition loss of brick,and density） and the main component analysis method were used to calculate the composite score of these five indicators. The effect of independent variables（ mass ratio of calcium fluoride sludge and red mud,dosage of clay,aluminum ash dosage,added amount of binder,and sintering temperature on composite score） on the composite score was also studied. Response surface methodology was used in the analysis of experimental data and the optimum conditions were determined（ i. e.,the mass ratio of calcium fluoride sludge and red mud = 61. 1%,dosage of clay = 21. 4%,aluminum ash dosage = 15%,added amount of binder = 2. 5%,sintering temperature = 1 000 ℃）. Under these conditions,the co-fired bricks had the following properties： the amount of fluoride ion leaching： 0. 33 mg·L^-1,the amount of chromium ion leaching： 0. 034 mg·L^-1,compressive strength： 5. 73 MPa,ignition loss rate： 9%,and the brick density： 1. 07 g·cm^（-3）. The bricks with these properties can be used as non-load-bearing bricks.
出处
《环境工程学报》
CAS
CSCD
北大核心
2017年第8期4797-4802,共6页
Chinese Journal of Environmental Engineering
关键词
拜耳法赤泥
氟化钙污泥
综合评分的计算
响应面分析法
Bayer red mud
calcium fluoride sludge
composite score calculation
response surface methodology
