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This article has been Na , K , NH 4 ‖ NO 3 - -H 2 O quaternary system equilibrium and the presence of additives under its relevant sub-system impact study balance rule, including: additive primaries; presence of additives under conditions K ‖ NO 3 - -H 2 O, NH 4 ‖ NO 3 - -H 2 O, Na ‖ NO 3 - -H 2 O binary system solubility rules change research; K , NH 4 ‖ NO 3 - -H 2 O, K , NH 4 < / sub> ‖ NO 3 - -H 2 O, K , NH 4 ‖ NO 3 - -H 2 O, CH 3 OH mixed solvent phase equilibrium studies, both from the perspective of statistical thermodynamics, phase equilibria of the system to establish a thermodynamic model: Na , K , NH 4 ‖ NO 3 - -H 2 O four yuan Salt System Equilibrium research. By measuring different concentrations of methanol, ethanol, acetone, ammonia, four kinds of additives on the crystallization of potassium law, methanol and ammonia found the precipitation of potassium best, followed by ethanol, acetone worst. Methanol and ammonia affect the solubility of binary system findings showed that: under the condition of constant temperature, the methanol concentration increases, potassium nitrate, ammonium nitrate, sodium nitrate has been reduced solubility; ammonia concentration, potassium nitrate, sodium nitrate solubility reduced, and increase the solubility of ammonium nitrate. On K , NH 4 ‖ NO 3 - -H 2 O phase equilibrium studies showed that the presence of five crystalline system: potassium nitrate and ammonium nitrate crystalline regions, ammonium nitrate and potassium nitrate eutectic crystallization zone, ammonium nitrate and ammonium nitrate crystals eutectic area, as well as a solid solution of ammonium nitrate crystallization zone. The results of previous fixes that this system is completely mixed potassium nitrate and ammonium nitrate solid solution region, there is no single crystal region conclusions, but also to fill the lack of the phase equilibrium data gaps. Select NH 3 and methanol as an additive, under different concentrations (methanol 10% ~ 60%, NH 3 5% ~ 25%) of additives on K , NH 4 ‖ NO 3 - -H 2 O system , the results showed that: 25 ℃ when, NH 3 concentration ≥ 20% ammonium nitrate crystallization zone system almost disappeared, the system only contains ammonium nitrate and potassium nitrate crystalline solid solution, and mainly as potassium nitrate crystallization zone; 10 ℃ when, NH 3 is a major concentration of ≥ 25% crystalline potassium nitrate, methanol concentration ≥ 50% solid solution crystal region disappears potassium nitrate and ammonium nitrate in the system completely separated crystalline, reached potassium separation. Meanwhile thermodynamic model for mixed solvent system calculations show that the model predictions with experimental data is good. On 10 ℃ Na , K , NH 4 ‖ NO 3 - -H 2 O quaternary system phase equilibria are discussed, the results show that the system consists of four crystalline regions: crystalline potassium nitrate, ammonium nitrate crystalline, sodium nitrate crystalline and crystalline solid solution of ammonium nitrate. The results of the system to fill the lack of phase equilibrium data gaps. This study will develop new technology to extract potassium nitrate to provide the appropriate data and theoretical basis.
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