磷酸盐废渣水蒸气热解处理研究

Study on Steam Pyrolysis of Phosphate Waste Residue

磷铝分子筛制备过程中产生含有机模板剂及磷酸盐的废水,在废水中加入调节助剂进行蒸发浓缩可回收有机胺,但同时产生大量磷酸盐废渣。为去除磷酸盐废渣中残留的有机模板剂以实现磷酸盐的资源化利用,采用水蒸气热解法对磷酸盐废渣进行深度处理,详细考察了助剂种类、水蒸气热解温度和水蒸气用量等条件的影响。结果表明,以氧化钙为调节助剂蒸发浓缩产生的磷酸盐废渣,经水蒸气热解处理后可得到符合GB/T 20412-2021《钙镁磷肥》肥料标准的资源化产品。在水蒸气与磷酸盐废渣质量比为30:100,于400℃水蒸气热解处理2 h后得到的固体产物中有机模板剂可完全去除,处理后废渣中的总有机碳≤0.5%(质量分数),有效磷≥30%。

During the preparation of aluminophosphate molecular sieve,wastewater containing organic template agent and phosphate was generated.Adding regulating additives in wastewater,organic amines could be recovered by evaporation concentration,but a large amount of phosphate waste residue was produced at the same time.In order to remove the remaining organic template agent in phosphate residue and realize the resource utilization of phosphate,the water steam pyrolysis method was used to treat the phosphate waste residue in depth,and the effects of regulating additives,water vapor pyrolysis temperature,water vapor dosage and other conditions were investigated in detail.The results showed that resource-based product which met the fertilizer standard of GB/T 20412-2021"Calcium,magnesium and phosphorus fertilizer"could be produced by steam pyrolysis treatment of the phosphate residue produced by evaporation concentration using calcium oxide as regulating additive.When the mass ratio of water vapor to phosphate waste residue was 30:100,the organic template of solid products produced after steam pyrolysis treatment at 400℃ for 2 h could be completely removed,with total organic carbon content≤0.5% and effective phosphorus content≥30%(mass fraction).