【摘要】 氨法烟气脱硫中，探明液相杂质对（NH₄）₂SO₄结晶的影响至关重要。采用SEM、XRD和粒径分析研究了不同浓度Fe³⁺和Al³⁺对（NH₄）₂SO₄结晶晶形及粒径分布的影响，并结合分子动力学模拟揭示了Fe³⁺和Al³⁺对（NH₄）₂SO₄结晶的影响机制。研究结果表明：当（NH₄）₂SO₄溶液中Fe³⁺的质量浓度低于200 mg/L或Al³⁺的质量浓度低于400 mg/L时，结晶后的晶体以规则棱柱状存在，平均粒径分别约为168μm和169μm，均匀性相对较高；当（NH₄）₂SO₄溶液中Fe³⁺质量浓度高于200 mg/L或Al³⁺质量浓度高于400 mg/L并不断增加时，（NH₄）₂SO₄晶体的晶形向片状转变，平均粒径和均匀性均呈下降趋势，且相比Al³⁺,Fe³⁺浓度增加对（NH₄）₂SO₄结晶的抑制作用更大；分子动力学模拟显示，Fe³⁺和Al³⁺与（NH₄）₂SO₄晶体（020）面的吸附能比（NH₄）₂SO₄分子与（NH₄）₂SO₄晶体（020）面的吸附能更负，（NH₄）₂SO₄易生成片状；Fe³⁺/Al³⁺浓度的增加使（NH₄）₂SO₄溶液pH降低，溶液介稳区变窄，致使过饱和度降低，最终导致晶体粒径减小。因此，可通过控制Fe³⁺和Al³⁺的浓度合理调控（NH₄）₂SO₄的结晶性能。更多还原

【Abstract】 In ammonia flue gas desulphurization,it is very important to determine the effect of liquid phase impurities on the crystallization of（NH₄）₂SO₄.In this paper,the effects of Fe³⁺ and Al³⁺ on the crystal shape and particle size distribution of（NH₄）₂SO₄ were studied by SEM,XRD and particle size analysis,and the effect mechanism of Fe³⁺ and Al³⁺ on the crystallization of（NH₄）₂SO₄ was revealed by molecular dynamics simulation.The results showed that when the concentration of Fe³⁺ in（NH₄）₂SO₄ solution was less than 200 mg/L or the concentration of Al³⁺ was less than 400 mg/L,the crystallized crystals existed in a regular prismatic shape with average particle sizes of about 168 μm and 169 μm,respectively,the uniformity was relatively high.When the concentration of Fe³⁺ in（NH₄）₂SO₄ solution was higher than 200 mg/L or the concentration of Al³⁺ was higher than 400 mg/L and continues to increase,the crystal shape of（NH₄）₂SO₄ crystal changes to sheet,and the average particle size and uniformity of（NH₄）₂SO₄ crystal showed a decreasing trend.Compared with Al³⁺,the increase of Fe³⁺ concentration had a greater inhibitory effect on the crystallization of（NH₄）₂SO₄.The molecular dynamics simulation showed that the adsorption energy of Fe³⁺/Al³⁺ and（NH₄）₂SO₄ crystal（020） surface was more negative than that of（NH₄）₂SO₄ molecule and（NH₄）₂SO₄ crystal（020） surface,and（NH₄）₂SO₄ was easy to form sheet.With the increase of Fe³⁺/Al³⁺ concentration,the pH of（NH₄）₂SO₄ solution was decreased,the metastable zone of solution was narrowed,resulting in the decrease of supersaturation,and ultimately the crystal size.Therefore,the crystallization properties of（NH₄）₂SO₄could be reasonably regulated by controlling the concentration of Fe³⁺ and Al³⁺.更多还原