Solubilities, Densities, and Refractive Indices in the Ternary Systems (LiBO₂ + NaBO₂ + H₂O) and (LiBO₂ + KBO₂ + H₂O) at 298.15 K and 0.1 MPa

Abstract

Solubilities, densities, and refractive indices of the two ternary systems (LiBO 2 + NaBO 2 + H 2 O) and (LiBO 2 + KBO 2 + H 2 O) at 298.15 K and 0.1 MPa were conducted with the method of isothermal solution saturation. The diagrams of solubilities, densities, and refractive indices were constructed using experimental data. They both contained one invariant point co-saturated with two salts, two biphasic regions, and one triphasic region. As the concentration of sodium metaborate (potassium metaborate) increases in solution, the density and refractive index change regularly and reach a maximum value at the invariant point. The densities and refractive indices change regularly with the sodium metaborate (potassium metaborate) concentration increasing in solution and reach the maximum value at the invariant point.

Solubilities, Densities, and Refractive Indices of the Ternary System (NaBO2 + KBO2 + H2O) at T = (298.15 and 323.15) K and P = 0.1 MPa

“…The form of boron species is affected by the pH, temperature, solution concentration, and so forth. The phase equilibrium of systems containing metaborate at multitemperatures has been reported, such as (NaCl + NaBO 2 + H 2 O) at (288.15, 298.15, and 308.15) K, , (Na 2 SO 4 + NaBO 2 + H 2 O) at (288.15, 298.15, and 308.15) K, , (NaOH + NaBO 2 + H 2 O) and (KOH + KBO 2 + H 2 O) at (283.15, 298.15, and 323.15) K, and (KBO 2 + LiBO 2 + H 2 O) and (NaBO 2 + LiBO 2 + H 2 O) at 298.15 K . The system (NaBO 2 + KBO 2 + H 2 O) is not only one of the most indispensable subsystems of the complex composition in Chaerhan Salt Lake brines, which should be studied primarily, but also is the theoretical guidance for separating boron salts from the brines.…”

“…Because the behavior of boron dissolution is very complex, borate exists in aqueous solution in the form of different species, such as [B 6 O 7 (OH) 6 ] 2– , [B 5 O 6 (OH) 4 ] − , [B 4 O 5 (OH) 4 ] 2– , [B 3 O 3 (OH) 5 ] − , [B 2 O­(OH) 6 ] 2– , [BO 2 ] − . The form of boron species is affected by the pH, temperature, solution concentration, and so forth.…”

Dissolution enthalpy and thermodynamic properties of potassium metaborate hydrate

“…15 K 的溶解度分别为 17.56 g/100 g [26] 和 3.34 g/100 g [27] , 与这两种钾硼酸盐相比, KBO 2 在水中的溶解度显著增大为 43.88 g/100 g [12] , 正 是因为偏硼酸钾的溶解焓较小, 其溶解熵也是正值, 极有利于溶解过程的进行, 导致 KBO 2 • 4/3H 2 O 在水中 溶解度增大. 根据热化学原理, 由文献 [28,29] 查得各物质的标准 生成熵代入下式 14…”

“…因此, KBO 2 的相关热力学参数的获取将 会为优化KBH 4 的合成路线提供理论数据. 而目前, 偏 硼酸钾还未商品化, 相关基础研究多集中在相平衡与 相图 [12][13][14][15] , 对其结构和热力学性质报道较少.…”

Thermodynamic Modeling of Boron Species in the Ternary System Na2O-B2O3-H2O at 298.15 K

“…e Qaidam Basin in Qinghai is the gathering place of salt lake resources in China [1]. In addition to the rich mineral resources such as potassium, sodium, magnesium, and lithium, the salt lake brine also has a large amount of borates [2][3][4][5]. ese resources have important application value for the development of industry, agriculture, and economic construction [6].…”