摘要
以电厂脱硫石膏为原料,利用重结晶原理制备二水硫酸钙晶须。考察了溶液过饱和度、硫酸浓度、陈化温度/时间以及降温速率对晶须生长特性的影响,并初步研究了硫酸钙晶须对含砷水溶液的除砷性能。结果表明:所研究的操作条件对晶须形貌、尺寸均有一定影响。在H2SO4溶液重结晶体系中,控制硫酸钙过饱和度为0.5、陈化温度为20℃、陈化时间为3 h并采用自然降温时,制备的二水硫酸钙晶须结晶度较好、形貌尺寸均匀,长径比为50～200。该二水硫酸钙晶须在pH为12时,能将初始浓度低于1 mg/L的含砷水溶液净化至满足地表水标准(0.05mg/L),展示了其在砷污染水体净化方面的应用潜力,可配合石灰-硫酸亚铁两段法除砷,降低废水处理成本。
Preparation of calcium sulfate whisker using flue gas desulfurization gypsum through recrystallization method was studied. The effects of operation parameters such as the degree of solution supersaturation, sulfuric acid concentration, aging temperature/time, and cooling rate on the growth characteristic of whiskers were investigated. Moreover, the performance of arsenic removal from a simulated solution by the whisker was also primarily studied for 0.05-5 mg/L initial arsenic concentration and 5-12 solution pH range. The results show that all the factors studied can affect the morphology and size of the whisker product, and the calcium sulfate dihydrate whisker with good crystallinity, identical morphology, and an aspect ratio = 50-200 can be obtained from sulfuric acid system under the conditions of a supersaturation of 0.5, 3-hours of aging, and a natural cooling rate in a 20 ~C indoor environment. When the solution pH value was 12, calcium sulfate dihydrate whisker exhibited excellent arsenic removal efficiency, and the residual arsenic concentration could be decreased to lower than the standard of surface water （0.05 mg/L） for an initial arsenic concentration less than 1 mg/L, which demonstrated a potential for purification of arsenic contaminated water. Combined with the traditional two stage method for arsenic removal with lime-ferrisulfas, application of calcium sulfate dihydrate whisker could decrease the total cost of wastewater treatment.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2013年第9期1889-1895,共7页
Journal of Synthetic Crystals
基金
湖南省教育厅项目(11C1213)
湘潭大学项目(2011XZX12
2010QDZ37)
关键词
脱硫石膏
重结晶法
二水硫酸钙晶须
砷
flue gas desulfurization gypsum
recrystallization
calcium sulfate dihydrate whisker
arsenic
