Study on phase equilibrium of the Mg2+, NH4+//Cl−, SO42−−H2O quaternary system at 363.15 K and its application

Nitrogen and magnesium compound fertilizer is an important and efficient fertilizer in the fertilizer industry. It can solve the problem of lack of sulfur, magnesium, and nitrogen in soil. MgCl2 can react with (NH4)2SO4 to produce Mg–N compound fertilizer. Therefore, the solid–liquid equilibrium data and physical properties (density and viscosity) of the quaternary system Mg2+, NH4 +//Cl–, SO4 2––H2O and its ternary subsystems Mg2+, NH4 +//Cl––H2O and Mg2+//Cl–, SO4 2––H2O at T = 303.15 K ± 0.05 K and P = 88.35 kPa were studied by an isothermal stripping equilibrium method. According to the experimental data, the phase diagram and physical property composition diagram of each system were drawn. The ternary subsystem Mg2+, NH4 +//Cl––H2O contains two invariant points and three crystallization regions. The ternary system Mg2+//Cl–, SO4 2––H2O contains four invariant points and five crystallization regions. The quaternary system Mg2+, NH4 +//Cl–, SO4 2––H2O contains seven invariant points and nine crystallization regions. MgCl2·NH4Cl·6H2O and MgSO4·(NH4)2SO4·6H2O exist in the quaternary system, and the quality of crops can be significantly improved by using the latter kind of complex salt. Therefore, this project is of great significance for the production of N–Mg compound fertilizers from magnesium resources in salt lake or other underground brines.

Section: Resultsmentioning

confidence: 99%

“…Multitemperature phase diagram of the ternary system Mg 2+ , NH 4 + //Cl – -H 2 O at 273.15, 298.15, and 363.15 K.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Solid–Liquid Phase Equilibria of Mg²⁺, NH₄⁺//Cl^–, SO₄²–H₂O at T = 303.15 K and P = 88.35 kPa

Zhang

Ding

et al. 2023

“…On the foundation of the analysis on the Pitzer model, it is found that β (0) , β (1) , β (2) , and C ϕ are the basic data which are bound to be ascertained primarily. These four parameters at 348.15 K can be calculated via eqs 1−3 18 using the least-squares method, which can be seen in Table 5.…”

Section: Resultsmentioning

confidence: 99%

“…On the foundation of the analysis on the Pitzer model, it is found that β (0) , β (1) , β (2) , and C ϕ are the basic data which are bound to be ascertained primarily. These four parameters at 348.15 K can be calculated via eqs – by relying on the values of β (0) , β (1) , β (2) , and C ϕ at 298.15 K and the corresponding partial derivative obtained from ref . All the results are listed in Table .…”

Section: Resultsmentioning

confidence: 99%

Solid–Liquid Equilibrium in the Ternary MgBr₂–MgSO₄–H₂O System at 348.15 K and Its Application

Guo

Cao

2021

The solid−liquid equilibrium of the ternary MgBr 2 −MgSO 4 − H 2 O system at 348.15 K was explored by using the isothermal equilibrium method, intending to realize the comprehensive utilization of the basic magnesium bromide (MgBrOH) waste residue produced in maltol production. It was observed that the phase diagram was composed of four single-salt crystallization regions, four univariate solubility curves, three invariant points saturated with

“…Unfortunately, similar articles from the same group have been published in this and other journals following the same pattern: short equilibration times (a few hours) in test tubes, claiming to have determined stable equilibria even in cases of solid-solution formation, Pitzer model not correctly reported, and technological applications therefore questionable. − …”

Section: Discussionmentioning

confidence: 99%

Comment on “Study on Phase Equilibrium of the K⁺, Mg²⁺//Cl^–, SO₄^2– + H₂O Quaternary System at 353.15 K and Its Application”

Voigt

Königsberger

2020

The experimental investigation of phase equilibria in this system at elevated temperatures is essential for improving the thermodynamic models describing the aqueous geochemistry of oceanic salts as well as for industrial processing of oceanic salt deposits. 2 However, an inspection of the article by Kang et al. 1 revealed that the experimental data, the thermodynamic model, and the presentation of the results do not meet scientific standards. In the following sections, we will comment on these three aspects (Table numbers refer to the paper of Kang et al.).