硫酸铵母液除氯及其对结晶影响

硫酸铵母液中Cl^-不断循环富集导致设备腐蚀严重，同时影响硫酸铵结晶及品质。本文运用硫酸钙铝法和脱硫灰铝法分别对硫酸铵母液进行除氯研究，采用筛分法对晶体粒径进行分析、扫描电子显微镜（Scanning Electron Microscope， SEM）对晶体尺寸、形貌进行表征，X射线衍射仪（X-ray Diffractometer，XRD）分析晶体物相。研究表明：除氯剂最佳投加量为3.0 g硫酸钙和0.8 g偏铝酸钠，3.0 g脱硫灰和0.8 g偏铝酸钠，对应除氯率分别为31.70%和36.38%。在转速200 r/min，反应温度为75 ℃，两种除氯剂加入会使ρ（Cl^-）快速下降，此为Cl^-与Ca²⁺和AlO₂^-反应形成了不溶钙铝氯化合物；除氯剂加入过量会使NaAlO₂发生双水解，解离出OH^-，抑制Cl^-与Ca²⁺、AlO₂^-反应，导致Cl^-去除率下降。硫酸钙铝法所产生的钙铝氯化合物会附着在晶粒活性表面进而增大硫酸铵结晶介稳区宽度，抑制晶体正常生长，导致结晶量减少；脱硫灰铝法中杂质金属可将OH^-消耗和减小硫酸铵结晶介稳区宽度，所含大量SO₄^2-会使硫酸铵结晶量增加，但晶体纯度降低。相关研究结果可为减少氨法脱硫设备腐蚀及优化硫酸铵结晶提供参考。

Effect of Chlorine Removal on Crystallization in the Mother Liquor of Ammonium Sulfate

Continuous cyclic enrichment of Cl^- in mother liquor of ammonium sulfate causes serious corrosion of equipment， while also affecting the crystallization and quality of ammonium sulfate. Dechlorination of the mother liquor of ammonium sulfate is investigated using calcium aluminum sulfate and desulfurized ash aluminum approach. A sieving approach is used to analyze the crystal size， scanning electron microscope is used to characterize the crystal size and morphology， and X-ray diffraction is used to analyze the crystal phase. The results show that the optimal dechlorination agent dosage is 3.0 g calcium sulfate and 0.8 g sodium metaaluminate， 3.0 g desulfurization ash and 0.8 g sodium metaaluminate， corresponding to dechlorination rates of 31.70% and 36.38%， respectively. At a rate of 200 r/min and a reaction temperature of 75 ℃， the addition of two dechlorinating agents causes the ρ（Cl^-） to drop rapidly. The reaction of Cl^- with Ca²⁺ and AlO₂^- forms insoluble calcium aluminum chloride compounds. Excessive NaAlO₂ causes double hydrolysis， dissociates OH^-， and inhibits the reaction of Cl^- with Ca²⁺ and AlO₂^-， resulting in a decrease in the rate of Cl^- removal. The calcium aluminum chloride compound forms using the calcium aluminum sulfate approach will adhere to the crystal grains′ active surface， thereby increasing the width of the ammonium sulfate crystal metastable zone， inhibiting the crystal′s normal growth， and reducing the number of crystals； the impurity metal in the desulfurization gray aluminum method can OH^- consumption and reduction of the width of the metastable zone of ammonium sulfate crystals， containing a large amount of SO₄^2- increases the amount of ammonium sulfate crystals， but reduce the crystal purity. The results of related studies can be used as a reference for reducing ammonia desulfurization equipment corrosion and enhancing ammonium sulfate crystallization.