【作者】 胡波；

【导师】 韩效钊；

【作者基本信息】 合肥工业大学 ， 化学工艺， 2005， 硕士

【摘要】 本文研究了钾长石与熔盐氯化钠离子交换反应的热力学和动力学,在1123-1273K反应温度下,反应的△GT⁰皆为负,反应可以自发进行,反应的△H_T⁰皆为负,反应为放热反应;在开始阶段内扩散为控制步骤,表观活化能为38.06J/mol,反应中、后期化学交换反应成为控制步骤,表观活化能为 129.69kJ/mol;利用二级动力学反应模型建立了交换反应的动力学方程。 正交实验得出,对于钾溶出率,较理想的实验条件为:原料配比0.8:1,反应温度150℃,磷酸用量3mL/（g磷矿粉）,反应时间2.5h,磷酸浓度49%P₂O₅;对于磷溶出率,较理想的实验条件为:反应时间2.5h,磷酸用量4.5mL/（g磷矿粉）,原料配比0.8:1,磷酸浓度44%P₂O₅,反应温度120℃。利用X射线衍射仪（XRD）、傅立叶红外光谱仪（FTIR）和拉曼光谱仪（Raman）对反应水不溶物进行物相分析和结构表征,表明钾长石、磷矿与磷酸反应机理同时存在两种机制:一方面是离子交换提钾,另一方面是氢氟酸分解钾长石提钾;磷矿中的氟离子反应后主要以不溶性的氟硅酸盐形式存在于固相中。 本文还考察了不同表面活性剂对提钾效果的影响,实验结果表明阳离子表面活性剂与钾长石的相容性最好,并以离子对形式吸附于钾长石表面,用量为500g/t时,钾溶出率提高8.26个百分点;阴离子表面活性剂与钾长石的相容性较好,用量为500g/t时,钾溶出率提高7.00个百分点;非离子和两性表面活性剂与钾长石的相容性较差,并未有效提高钾溶出率:混合表面活性剂比单一表面活性剂更有利于提高钾溶出率,当用量为500g/t,且阴、阳离子表面活性剂质量配比为3:1,钾溶出率提高8.62个百分点。更多还原

【Abstract】 This paper studies the thermodynamics and kinetics of the ion exchange reaction between the potassium ions from potash feldspar and the sodium ions from solutions. With different reaction temperatures that is from 1123K to 1273K thermodynamic analyses demonstrate the feasibility of the ion exchange reaction because the values of △Gt0 are totally negative and the exothermic reaction because the values of △Ht° are totally negative .Ion exchange kinetic models that are composed of two controlled steps are established to represent the relation of the reaction velocity with the reaction temperature and time, While inner diffusion become rate-determining step, apparent activation energies is around 38.06kJ/mol, then chemical exchange became rate-determining step , and apparent activation energies turn into around 129.69 kJ/mol. Since chemical exchange becomes rate-determining step at the end of the ion exchange reaction, an experimental ion exchange kinetic equation is work out on the basis of the second-order kinetic model.At the extraction potassium from potash feldspar with phosphorite in the acid environment, the relatively perfect experiment conditions of the potassium leaching rate are confirmed as follow, material ratio（weight） m（phosphorite） : M（potash feldspar） =0.8:1, phosphorus acid : 3mL/g phosphorite, concentration of the phosphorus acid 49%P₂O₅, temperature 150℃, time 2.5h; the relatively perfect experiment conditions of the phosphorine leaching rate are confirmed as follow, material ratio（weight） m（phosphorite） : M（potash feldspar） =0.8:1, phosphorus acid : 4.5mL/g phosphorite, concentration of the phosphorus acid 44%P₂O₅, temperature 120℃, time 2.5h. Experimental non-soluble results of characterization by X-ray diffraction （ XRD ） （ FTIR ） and （ Raman ） show that there are two theories coexistent: one is that potassium extraction by ion exchange reaction, then the other is that HF dissociates potash feldspar; thermodynamic analyses demonstrate the feasibility of the ion exchange reaction with experimental temperature, which firmly demonstrates the mechanism; the direction of fluoric ions that originally exists in the phosphorite are studied by X-ray diffraction （ XRD ） and chemical analysis, and the experimental results show that fluoric ions are totally consisted in the non-soluble fluorine silicate.Finally, compared with the effects of different surfactants on the operation conditions, and experimental results show that cationic surfactant which absorb on the surface of potash feldspar have the best adaptable with potash feldspar, as a result while the dosage is 500g/t, so the value of the potassium leaching rate has an increase about 8.26; anionic surfactant have a good adaptability with potash feldspar, as a result while the dosage is 500g/t, so the value of the potassium leaching rate has an increase about 7.00; amphiprotic and non-ionic surfactant had a bad adaptability with potash feldspar as it did not effectively affected the potassium leaching rate. Mixed surfactant has a better potassium extraction degree than single surfactant, as a result while the dosage is 500g/t as well as the weight ratio of the cationic surfactant and the anionic surfactant is 3:1 , so the value of the potassium leaching rate has an increase about 8.62.更多还原