Cl

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Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Phase Equilibria of the Reciprocal Quaternary System (Na+, Ca2+//Cl−, Borate−H2O) at 288.15 K and 0.1 MPa Mengxue Wang,† Lianying Lei,† Yafei Guo,*,† Lingzong Meng,†,‡ Shiqiang Wang,† and Tianlong Deng†

J. Chem. Eng. Data Downloaded from pubs.acs.org by UNIV OF LOUISIANA AT LAFAYETTE on 10/19/18. For personal use only.

†

Tianjin Key Laboratory of Marine Resources and Chemistry, College of Chemical Engineering and Materials Science, Tianjin University of Science and Technology, Tianjin 300457, PR China ‡ School of Chemistry and Chemical Engineering, Linyi University, Linyi 276000, PR China ABSTRACT: To exploit the valuable features of brine resources with high concentrations of borate ions, the solubility data and corresponding physicochemical properties (refractive index, density, viscosity, and pH) for the reciprocal quaternary system (Na+, Ca2+//Cl−, borate−H2O) at 288.15 K were determined experimentally using the method of isothermal dissolution equilibrium. The dry-salt and water-phase diagrams and the diagrams of physicochemical properties (refractive index, density, viscosity, and pH) against J(B4O72−) in the solution were established. In the dry-salt phase diagram of the quaternary system at 288.15 K, two invariant points, five univariant curves, and four crystallization regions corresponding to gowerite (CaB6O10·5H2O), borax (Na2B4O7· 10H2O), antarcticite (CaCl2·6H2O), and sodium chloride (NaCl) were found. The area of crystallization region of CaB6O10·5H2O is larger than that of other coexisting salts, which indicates that the solubility of gowerite in this system is the lowest and that it is more easily separated by crystallization; the areas of crystallization regions of Na2B4O7· 10H2O, NaCl, and CaCl2·6H2O are decreased in turn. In this system, there are no double salts or solid solutions experimentally found. The water-phase diagram of the system indicates regular variation of J(H2O) on J(B4O72−), and the physicochemical properties of the quaternary system varied regularly with increasing Jänecke index values of J(B4O72−).

1. INTRODUCTION Calcium borates are important chemical raw materials, and they are widely used in pharmaceuticals, glass, paint, flame retardants, and steel and ceramics industries.1,2 Salt lake brines, underground water, and geothermal resources with high concentrations of sodium; calcium; borates; and the rare elements lithium, rubidium, and cesium are widely distributed in Bolivia, Chile, Argentina, and China.3−5 Among them, there are abundant oilfield brine resources in the Qaidam Basin, China with the main characteristics of low sulfate concentration, high calcium concentration, and high salinity. Moreover, the valuable brine contains the calcium chloride-type brine as a complex six-component system (Li+, Na+, K+, Ca2+//Cl−, borate−H2O).6 There is no doubt that phase equilibria and phase diagrams are significant in guiding the comprehensive utilization of the valuable brine. To take full advantage of the brine resources, the phase equilibria of some subsystems containing calcium have been researched, such as (NaCl + LiCl + CaCl2 + H2O) at 288.15 K;7 (NaCl + KCl + CaCl2 + H2O) at 288.15 K;8 (LiBO2 + CaB2O4 + H2O) at 288.15 and 298.15 K;9 (NH4Cl + CaCl2 + H2O) at 298.15, 323.15, and 348.15 K;10 (CaCl2 + CaB6O10 + H2O) at 308.15 and 323.15 K;11 and (NaCl + KCl + CaCl2 + H2O) at 308.15 K.12 Although the phase equilibrium and phase diagrams of calcium-containing systems over a wide temperature range have been previously reported, research has mainly focused on ternary and simple quaternary systems; the solubility data of more complex systems is seriously insufficient. Halite © XXXX American Chemical Society

NaCl usually exists in the solution in the evaporation process of oil-field brine; therefore, it is of great significance to study the phase equilibrium of the reciprocal quaternary system (Na+, Ca2+//Cl−, borate−H2O) for the exploitation of calcium borate from abundant oil-field brines, which is not yet reported in the literature. In this paper, the solubility data and physicochemical properties (refractive index, density, viscosity, and pH) of the reciprocal quaternary system (Na+, Ca2+//Cl−, borate−H2O) at 288.15 K are presented.

2. EXPERIMENTAL SECTION 2.1. Apparatus and Reagents. A magnetic stirring thermostatic bath (HXC-500-12A, Beijing Fortune Joy Sci. Technol. Co., Ltd.) was used for temperature control, and the precision was within ±0.1 K. Refractive indices (nD) were measured by an Abbe refractometer (Abbemat 550, Anton Paar, Austria) with an uncertainty of ±0.0003. The densities (ρ) were measured by a vibrating-tube densitometer (DMA4500, Anton Paar, Austria) with an uncertainty less than ±1.4 mg·cm−3. The viscosities (η) were determined by a Lovis2000m capillary viscometer (Anton Paar, Austria) with an uncertainty of ±0.03 Pa·s. The pH values were determined by a high-precision pH meter with an Received: March 24, 2018 Accepted: October 15, 2018

A

DOI: 10.1021/acs.jced.8b00234 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

Table 1. Chemicals Used in the Study chemical name

CAS registry number

sourcea

initial mass fraction purity

purification method

final mass fraction purity

analysis method

NaCl H3BO3 Ca(OH)2 CaCl2·6H2O Na2B4O7·10H2O CaB6O10·5H2O

7647-14-5 7647-14-5 1305-62-0 7774-34-7 1303-96-4 12291-65-5

A.R. A.R. A.R. A.R. A.R. −b

0.99 0.99 0.99 0.99 0.99 0.99

recrystallization recrystallization recrystallization recrystallization recrystallization recrystallization

0.995 0.996 0.996 0.998 0.997 0.995

titration for Cl− gravimetric method for B2O3 titration for Ca2+ titration for Cl− gravimetric method for B4O72− gravimetric method for B6O102−

a

A.R. from the Sinopharm Chemical Reagent Co., Ltd. bSynthesized in our laboratory.

Figure 1. X-ray diffraction pattern of gowerite (CaB6O10·5H2O).

uncertainty of ±0.003 (PH-7310, WTW Co. Ltd., Germany). Before experiments, the pH meter was calibrated using a calibration solution with pH of 4.00, 7.00, and 10.01, and the refractometer, densitometer, and viscometer were calibrated by ultrapure water to ensure data quality. The solid-phase samples were identified by an X-ray diffractometer (MSAL XD-3, Beijing Purkinje Instrument Co. Ltd., China). All data on physicochemical properties in this work were measured in triplicate, and the average was taken for calculation. The chemicals used in this work are tabulated in Table 1, and they were of analytical purity grade and recrystallized before experiment. In this work, gowerite (calcium hexaborate pentahydrate, CaB6O10·5H2O) was synthesized using a modified method by the interaction of lime and boric acid at temperatures of (358.15−378.15) K, which was described previously.13 The chemical analysis and X-ray diffraction (XRD) characterization are shown in Table 1 and Figure 1, and the results indicated that the synthesized CaB6O10·5H2O could be used for further work. Fresh CO2-free doubly deionized water (DDW) with conductivity less than 1.2 × 10−4 S·m−1 and pH 6.60 was used to prepare the series of the artificial synthesized samples and for chemical analysis. 2.2. Experimental Methods. The isothermal dissolution method was carried out in this work.14 On the basis of the phase equilibrium composition, salts and water of appropriate quantity were mixed together and loaded into a series of cleaning polyethylene containers. After that, the containers were placed in the magnetic stirring thermostatic bath and the temperature was set at (288.15 ± 0.1) K with 150 rpm to accelerate the achievement

of equilibrium. At intervals, a 5.0 cm3 sample of the clarified solution was taken out with a pipet for chemical analysis. If the composition of each solution was constant, it can be concluded that the equilibrium of specific system was obtained. Then, the magnetic stirring was stopped and the system stood for 4 h. When the system was equalizing, the liquid supernatant was taken out for quantitative chemical analysis and the wet solid was identified by XRD analysis.14 2.3. Analytical Methods. The Cl− concentration was determined by volumetric titration with Hg(NO3)2 standard solution using an indicator of potassium chromate within an uncertainty of ±0.003 in mass fraction.15 The concentrations of B4O72− and B6O102− were measured by the modified mannitol gravimetric method with the uncertainty of ±0.0005.15 The principle of the modified mannitol gravimetric analysis method for borates in this work is as follows: ij m m yz mB = jjj NaOH 2 zzz z j 2m 1 { k

where mNaOH refers to the molar concentration of NaOH and m1 and m2 represent the weight of the aqueous sample and NaOH solution used, respectively. Thus, the total concentration of boron could be obtained. It is worth mentioning that although the forms of borates in the solid phase could be identified exactly, the form of borates in aqueous solution is complex. It generally includes BO2−, B4O72−, B6O102−, and so on and depends on the concentration of the total boron and counterion in the solution.16 However, the separate certain concentrations of B4O72− and B6O102− are difficult to determine by present B



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Table 2. Solubilities and Physicochemical Properties of the Reciprocal Quaternary System (Na+, Ca2+//Cl−, Borate−H2O) at 288.15 K and 0.1 MPaa Jänecke index, Jb/[mol/100 mol (2Cl− + B4O72−)]

composition in the solution (100w)

physicochemical properties

J(Na22+)

J(H2O)

nD

ρ/ (g·cm−3)

η/ (mPa·s)

pH

equilibrium solid phaseb

0.97 1.04 1.04 1.12 1.15 1.19 1.17 1.32 1.52 1.96 2.01 2.01 2.02 2.02 2.00 2.03 100.00

99.33 96.72 95.41 88.44 88.07 88.67 86.52 77.87 77.30 74.42 62.38 61.86 39.38 25.81 23.80 16.85 95.65

1808.82 1726.14 1725.16 1709.74 1714.78 1718.60 1694.62 1698.38 1606.72 1744.74 1715.89 1686.05 1673.57 1563.79 1559.98 1474.50 24081.42

1.3818 1.3817 1.3816 1.3817 1.3816 1.3816 1.3816 1.3817 1.3820 1.3877 1.3908 1.3862 1.3963 1.4060 1.4031 1.4044 1.3816

1.19597 1.20571 1.20580 1.20595 1.20510 1.20528 1.20535 1.20574 1.20590 1.22128 1.23040 1.21859 1.24395 1.27120 1.26288 1.26683 1.20252

1.86 1.92 1.93 1.93 1.88 1.94 1.97 1.90 2.37 2.55 2.75 2.55 2.99 3.23 3.15 3.45 1.96

8.482 8.411 8.437 7.772 7.953 8.243 8.310 7.881 7.560 6.005 5.745 6.074 5.395 4.958 5.072 5.048 8.453

Nc + Nb Nc + Nb Nc + Nb Nc + Nb Nc + Nb Nc + Nb Nc + Nb Nc + Nb Nb + Cb5 + Nc Nc + Cb5 Nc + Cb5 Nc + Cb5 Nc + Cb5 Nc + Cb5 Nc + Cb5 Nc + Cb5 Nb + Cb5

96.00 95.83 95.62 94.33 94.31 93.70 93.38 92.50 78.88 78.21 77.58 76.25 59.16

64.96 59.01 45.20 34.86 32.55 32.15 14.39 12.71 7.59 7.31 6.68 4.94 0.03

95.03 95.24 95.25 95.39 95.75 95.20 95.31 95.51 94.61 92.90 91.54 85.93 0.00

22845.42 21195.17 18761.45 13521.19 13256.96 11867.75 10060.09 8712.97 2593.56 2468.03 2352.70 2159.71 892.24

1.3385 1.3392 1.3400 1.3415 1.3404 1.3423 1.3448 1.3456 1.3817 1.3818 1.3819 1.3720 1.4493

1.02470 1.02741 1.03031 1.03664 1.02938 1.03677 1.04674 1.05067 1.20678 1.20517 1.20706 −c 1.41102

1.26 1.26 1.27 1.26 1.25 1.27 1.30 1.29 2.36 − 2.35 − −

8.742 8.542 8.367 8.102 8.138 7.927 7.787 7.805 6.681 6.761 6.866 6.687 4.072

Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Nb + Cb5 Cc6 + Cb5

26.75 26.69 26.54 27.57 27.71 27.66 25.97 26.74

57.99 57.96 58.03 56.55 55.92 55.94 58.74 57.85

0.33 0.39 0.50 0.60 0.65 0.72 0.77 0.00

0.75 1.09 1.33 1.78 1.99 2.16 2.95 1.79

850.99 851.96 856.99 803.04 789.73 790.81 884.06 852.12

1.4488 1.4473 1.4460 1.4461 1.4461 1.4461 1.4455 1.4458

1.41065 1.41712 1.41047 1.41012 1.41058 1.41018 1.41819 1.41046

11.28 12.86 11.87 12.90 12.59 12.72 13.18 12.40

2.990 2.870 2.652 2.891 3.045 3.085 3.938 8.430

Cc6 + Cb5 Cc6 + Cb5 Cc6 + Cb5 Cc6 + Cb5 Cc6 + Cb5 Cc6 + Cb5 Cc6 + Nc + Cb5 Cc6 + Nc

25.73 25.78 26.08 25.98

59.76 59.47 58.66 58.52

0.05 0.14 0.28 0.54

1.98 2.27 2.42 2.72

914.33 907.45 883.54 882.49

1.4436 1.4392 1.4455 1.4451

1.40112 1.38420 1.40191 1.40694

10.90 9.06 11.86 11.52

5.254 5.144 4.500 4.332

Cc6 + Nc Cc6 + Nc Cc6 + Nc Cc6 + Nc

no.

w(Na+)

w(Ca2+)

w(B4O72−)

w(Cl−)

1, E1 2 3 4 5 6 7 8 9, F1 10 11 12 13 14 15 16 17, E2 18 19 20 21 22 23 24 25 26 27 28 29 30, E3 31 32 33 34 35 36 37, F2 38, E4 39 40 41 42

10.31 10.35 10.23 9.57 9.51 9.55 9.43 8.48 8.75 7.94 6.75 6.80 4.36 3.00 2.77 2.04 0.97

0.000 0.631 0.622 1.094 1.123 1.150 1.226 2.064 2.277 2.348 3.478 3.288 5.611 7.500 7.764 8.950 0.003

0.3401 0.3752 0.3781 0.4074 0.4180 0.4312 0.4294 0.4846 0.5808 0.7058 0.7349 0.7453 0.7536 0.7908 0.7873 0.8312 3.4239

15.85 16.33 16.36 16.50 16.46 16.41 16.61 16.57 17.19 16.13 16.35 16.61 16.73 17.56 17.59 18.29 0.00

73.50 72.31 72.41 72.43 72.49 72.46 72.30 72.40 71.20 72.88 72.69 72.56 72.55 71.15 71.09 69.89 95.60

1.02 1.10 1.24 1.70 1.74 1.92 2.26 2.59 7.35 7.52 7.71 7.75 0.00

0.048 0.039 0.056 0.079 0.067 0.078 0.075 0.096 0.714 0.702 0.693 1.273 14.713

2.3541 2.3010 1.9869 2.0977 1.9969 2.1895 1.1523 1.1641 1.9903 1.9972 1.9003 1.5043 0.0158

0.58 0.73 1.10 1.79 1.89 2.11 3.13 3.65 11.07 11.57 12.12 13.22 26.11

0.13 0.19 0.23 0.32 0.36 0.39 0.50 0.31

14.940 14.932 14.910 15.200 15.614 15.570 14.352 15.102

0.1949 0.2309 0.2891 0.3632 0.3959 0.4420 0.4394 0.0000

0.33 0.38 0.41 0.46

14.152 14.287 14.685 14.731

0.0297 0.0782 0.1604 0.3074

w(H2O) J(B4O72−)

a Standard uncertainties u are u(T) = 0.1 K and u(p) = 0.005 MPa. u(w) for Na+, Ca2+, Cl−, B4O72−, and B6O102− are 0.005, 0.003, 0.003, 0.0005, and 0.0005 in mass fraction, respectively; u(x) for nD, ρ, pH, and η are 0.0003, 1.4 mg·cm−3, 0.003, and 0.03 mPa·s, respectively. bNc, NaCl; Nb, Na2B4O7·10H2O; Cc6, CaCl2·6H2O; Cb5, CaB6O10·5H2O cNot measured.

emission spectrometry (Prodigy, Leman Co., United States) with standard uncertainty of ±0.005 in mass fraction.

analytical techniques. Therefore, on the basis of the statistical principle of group contribution, the concentration of the total borates in aqueous solution was expressed in B4O72−, which is also the most frequently expressed form in the literature at present.17 The concentration of Ca2+ ion was analyzed by titration with an EDTA standard solution in alkali medium with a Ca-indicator, with an uncertainty of ±0.003 in mass fraction.15 The Na+ ion was evaluated using ion balance combined with analytical verification using inductively coupled plasma−optical

3. RESULTS AND DISCUSSION 3.1. Phase Diagrams of the Reciprocal Quaternary System at 288.15 K. The experimental data on the solubilities and physicochemical properties (refractive index, density, viscosity, and pH) of the reciprocal quaternary system (Na+, Ca2+//Cl−, C



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Table 3. Comparison of the Solubility Data in This Work and the Literature at the Invariant Points of the Boundary Subsystems and the Relevant Binary Systems composition of the solution (100w) subternary system Na+, Ca2+//Cl−−H2O Ca2+//Cl−, B6O102−−H2O Na+//Cl−, B4O72−−H2O

CaB6O10−H2O CaCl2−H2O NaCl−H2O Na2B4O7−H2O

T /K

w(NaCl)

w(Na2B4O7)

w(CaB6O10)

w(CaCl2)

w(H2O)

reference

288.15 (metastable) 288.15 288.15

0.55 0.78 0 0 26.03 26.08 26.30 25.97 0 0 26.30 0

0 0 0 0 0.56 0.40 0.65 0.47 0 0 0 2.12

0 0 0.018 0.02 0 0 0 0 0.11 0 0 0

40.45 41.91 40.82 40.82 0 0 0 0 0 41.20 0 0

59.00 57.31 59.16 59.16 73.41 73.52 73.05 73.56 99.89 58.50 73.70 97.88

18 this work 19 this work 20 21 21 this work 19 21 21 22

288.15 (metastable) 283.15 293.15 288.15 288.15 288.15 288.15 288.15

Figure 2. Dry-salt phase diagram (a) and enlarged portion (b) of the quaternary system (Na+, Ca2+//Cl−, borate−H2O) at 288.15 K.

For the reciprocal quaternary system, the Jänecke index is a common expression of the concentration of specific ions in the quaternary system, and it is an equivalent mole valence in the quaternary system.14 The Jänecke index values of separate ions and water can be calculated by the following correlations:

borate−H2O) at 288.15 K are presented in Table 2. Although there are four boundary subternary systems in this reciprocal system, only three subternary systems [(Na+, Ca2+//Cl−−H2O), (Ca2+//Cl−, B6O102−−H2O), and (Na+//Cl−, B4O72−−H2O)] for their stable or metastable solubilities have been reported in the literature.18−22 Solubilities of the invariant points for the three subternary systems are shown in Table 3. In the sub-boundary ternary system (Na+, Ca2+//Cl−−H2O),18 the solubility in the invariant point of the ternary system (Na+, Ca2+//Cl−−H2O) at 288.15 K is the nonthermodynamic solubility because it is a solar evaporating solubility in the invariant point of this ternary system. For the second boundary subternary system (Ca2+//Cl−, B6O102−−H2O), the solubilities in the invariant point obtained in this work are almost the same. For the third boundary subternary system (Na+//Cl−, B4O72−−H2O), besides the metastable solubilities for this system at 288.15 K, there is no solubility data at 288.15 K in the literature; therefore, the solubilities at the close temperatures of 283.15 and 293.15 K in the literature were listed for comparison in Table 3. In addition, the solubilities of the four binary systems (NaCl−H2O), (CaCl2−H2O), (CaB6O10−H2O), and (Na2B4O7−H2O) from the literature are presented in Table 3. The results show that the data for the subternary systems in the literature agree well with our experimental results, indicating the experimental procedure and analysis are rational and reliable.

[Z ] =

w(B4 O7 2 −) 2w(Cl−) + M(Cl−) M(B4 O7 2 −) 100w(Na +) M(Na 2 2 +) ·[Z ]

J(Na 2 2 +) =

J(B4 O7 2 −) =

J(H 2O) =

(1)

(2)

100w(B4 O7 2 −) M(B4 O7 2 −) ·[Z ]

100w(H 2O) M(H 2O) ·[Z ]

(3)

(4)

where w(ionic) and w(H2O) are the concentrations of the relative contents of ions or water in solution in mass fraction and [Z] is the total equivalent valence moles of anions. The Jänecke index (Jb, Jb/[mol/100 mol (2Cl− + B4O72−)]), i.e. J(ionic) and J(H2O), are the Jänecke index of ions and water; M represents D



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Figure 3. Water-phase diagram (a) and enlarged portion (b) of the quaternary system (Na+, Ca2+//Cl−, borate−H2O) at 288.15 K.

Figure 4. X-ray diffraction pattern of the invariant points F1 (Nc + Nb + Cb5) (a) and F2 (Nc + Cc6 + Cb5) (b).

the molecular weight of the specific ion, and the molecular weight of water is 18.

Based on the Jänecke index for the reciprocal quaternary in Table 2, the dry-salt phase diagram and the water-phase diagram E



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Figure 5. Physiochemical properties versus composition of the quaternary system (Na+, Ca2+//Cl−, borate−H2O) at 288.15 K: (a) refractive index vs J(B4O72−), (b) density vs J(B4O72−), (c) viscosity vs J(B4O72−), and (d) pH value vs J(B4O72−).

congruent and incongruent invariant points.14 The point F1 corresponding to the equilibrium solid phase is (Nc + Cb5 + Nb), and the location of F1 is beyond the triangle consisting of the solid-phase points of (Nc + Cb5 + Nb), indicating F1 belongs to the incongruent invariant point; the composition of the equilibrated solution in mass fraction 100w for Na+, Ca2+, B4O72−, Cl−, and H2O is 8.75, 2.2368, 0.5808, 17.19, and 71.24, respectively. However, the point F2 corresponding to the equilibrium solid phase (Nc + Cb5 + Cc6) is a congruent invariant point, and the composition of the equilibrated solution in mass fraction 100w for Na+, Ca2+, B4O72−, Cl−, and H2O is 0.5, 14.3523, 0.4394, 25.97, and 58.73, respectively. Moreover, there are no double salts or solid solutions found in the quaternary system, which clarified that the quaternary system (Na+, Ca2+//Cl−, borate−H2O) is of simple common saturation. The water-phase diagram of the reciprocal quaternary system at 288.15 K is shown in Figure 3. It shows that the Jänecke index values of J(H2O) gradually change with the increasing of J(B4O72−). On the curve E3F2E4, J(H2O) increases because of the continuous decrease of CaCl2 content. Compared with F1 and F2, the solubility of CaCl2 is much larger than that of other salts, so the J(H2O) at F2 is higher. On the curve F1E2, with the decrease of CaCl2 content, J(H2O) increases sharply and reaches the maximum value of J(H2O) by E2, which indicates the quite low solubility of borax.

of the quaternary system at 288.15 K are plotted in Figures 2 and 3, respectively. As shown in Figure 2, the dry-salt phase diagram of the quaternary system at 288.15 K consists of four crystallization zones corresponding to gowerite (CaB6O10·5H2O, Cb5), borax (Na2B4O7·10H2O, Nb), antarcticite (CaCl2·6H2O, Cc6), and sodium chloride (NaCl, Nc). The crystallization zone of CaB6O10·5H2O is larger than that of others, which indicates that gowerite is of the lowest solubility and easy to precipitate, and the crystallization zones of Na2B4O7·10H2O, NaCl, and CaCl2·6H2O are decreased in order. There are five univariant curves corresponding to curves E1F1 (Nb + Nc), E2F1 (Nb + Cb5), E3F2 (Cc6 + Cb5), E4F2 (Nc + Cc6), and F1F2 (Nc + Cb5), coexisting with two salts and an equilibrated solution, respectively. Because of the relative high solubilities of NaCl and CaCl2 in the solution, there is a strong salting-out effect to gowerite. There are four ternary subsystems of the reciprocal quaternary system (Na+, Ca2+//Cl−, borate−H2O). In Figure 2, points E1, E2, E3, and E4 are invariant points of the ternary subsystems, points F1 and F2 are invariant points of the quaternary system (Na+, Ca2+//Cl−, borate−H2O). The composition of the cosaturated salts of F1 and F2 have been identified by X-ray diffraction and are shown in Figure 4. Actually, there are two kinds of invariant points in phase diagrams including the F



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(2) Han, X.; Day, D. E. Reaction of sodium calcium borate glasses to form hydroxyapatite. J. Mater. Sci.: Mater. Med. 2007, 18, 1837−1847. (3) Li, J. S.; Li, W. T.; Li, H. Z.; Peng, X. M. Investigation of the chemical characteristics and its geological significance of the Tertiary oil-field brine in the western Qaidam basin. Hydrogeol. Eng. Geol. 2013, 40, 28−36. (4) Yanagase, K.; Yoshinaga, T.; Kawano, K.; Matsuoka, T. The recovery of lithium from geothermal water in the Hatchobaru area of Kyushu. Bull. Chem. Soc. Jpn. 1983, 56, 2490−2498. (5) Trócoli, R.; Battistel, A.; Mantia, F. L. Selectivity of a lithiumrecovery process based on LiFePO4. Chem. - Eur. J. 2014, 20, 9888− 9891. (6) Li, H. Q.; Gu, T. X.; Yu, S. S.; Yao, Y.; Li, B.; Li, W. Study on the precipitation pathway of nanyishan oil-field brine at subzero temperatures. Acta Phys. Chim. Sin. 2011, 27, 1803−1808. (7) Deng, T. L.; Li, D. Solid-liquid metastable equilibria in the quaternary system (NaCl + LiCl + CaCl2 + H2O) at 288.15 K. J. Chem. Eng. Data 2008, 53, 2488−2492. (8) Deng, T. L.; Li, D. C. Solid-liquid metastable equilibria in the quaternary system (NaCl -KCl -CaCl2 -H2O) at 288.15 K. Fluid Phase Equilib. 2008, 269, 98−103. (9) Wang, S. Q.; Guo, Y. F.; Liu, W. J.; Deng, T. L. Phase equilibria in the aqueous ternary system (LiBO2 + CaB2O4 + H2O) at 288.15 and 298.15 K. J. Solution Chem. 2015, 44, 1545−1554. (10) Dong, O. Y.; Zeng, D. W.; Zhou, H. Y.; Han, H. J.; Yin, X.; Du, Y. Phase change materials in the ternary system NH4Cl + CaCl2 + H2O. CALPHAD: Comput. Coupling Phase Diagrams Thermochem. 2011, 35, 269−275. (11) Lei, L. Y.; Li, L.; Cao, L. N.; Guo, Y. F.; Zhang, S. S.; Wang, S. Q.; Deng, T. L. Solid−liquid phase equilibria of the aqueous ternary system (CaCl2 + CaB6O10 + H2O) at 308.15, 323.15 K and 0.1 MPa. J. Chem. Eng. Jpn. 2017, 50, 231. (12) Li, D. C.; Deng, T. L. Liquid-solid metastable phase equilibria for the quaternary system (NaCl-KCl-CaCl2-H2O) at 308.15 K. J. Therm. Anal. Calorim. 2009, 95, 361−367. (13) Schubert, D. M. Method for producing calcium borate. U.S. Patent US5688481A (1997). (14) Deng, T. L.; Zhou, H.; Chen, X. Salt−Water System Phase Diagrams and Applications; Chinese Chemical Industry Press: Beijing, 2013; pp 1−326. (15) Analytical Lab of Qinghai Institute of Salt Lakes at CAS. The Analyses of Brines and Salts; Science Press: Beijing, China, 1988; pp 55− 64. (16) Zhou, Y. Q.; Fang, C. H.; Fang, Y.; Zhu, F. Y. Polyborates in aqueous borate solution: a Raman and DFT theory investigation. Spectrochim. Acta, Part A 2011, 83, 82−87. (17) Yang, J. M.; Yao, Y.; Xia, S. P.; Li, B. H.; Xu, S. Y.; Yang, J. Isopiestic determination of the osmotic coefficients and Pitzer model representation for the Li2B4O7 + LiCl+H2O system at T = 298.15 K. J. Solution Chem. 2008, 37, 377−389. (18) Zhao, Q. W.; Tu, L. Y.; Guo, Z. P. Evaporation solar pond from distilled ammonia liquid. Modern Chem. Ind. 2014, 34, 137−140. (19) Lei, L. Y.; Zhao, K. Y.; Guo, Y. F.; Yu, X. P.; Zhang, S. S.; Wang, S. Q.; Meng, L. Z.; Deng, T. L. Solubilities, densities, refractive indices and pH values of the aqueous ternary system of calcium chloride and calcium hexaborate at 288.15, 298.15 K and 0.1 MPa. J. Chem. Eng. Jpn. 2018, 51, in press. (20) Yang, L. J.; Lin, C. X.; Wang, S. Q.; Guo, Y. F.; Deng, T. L. Metastable equilibria of the aqueous ternary system of sodium chloride and sodium borate at 288.15 K. China Sciencepaper 2013, 8, 584−586. (21) Databases of Salt-water Systems. http://www.ourwaystd.com (Accessed June 1, 2016). (22) Teeple, J. E. The Industrial Development of Searles Lake Brines with Equilibrium Data; Chemical Catalog Co.: New York, 1929; pp 1−181.

3.2. Physicochemical Properties of the Reciprocal Quaternary System at 288.15 K. According to the experimental data of physicochemical properties in Table 2, the diagrams of physicochemical properties versus composition for the quaternary system (Na+, Ca2+//Cl−, borate−H2O) at 288.15 K are plotted in Figure 5. It is shown that physicochemical properties of the quaternary system at 288.15 K vary regularly with a changed Jänecke index of B4O72−. When panels a−d of Figure 5 on the univariate solubility curves E1F1and E2F1 are compared, with the increase of J(B4O72−), the refractive index, density, and viscosity increased obviously, while pH decreased gradually. However, because of the strong salting-out of CaCl2 to borate, refractive index, density, and viscosity decreased first and then increased, reaching the maximum value at F1. From the invariant point of F1 to F2, because of a substantial increase in the content of Cl− and because the total amount of borate was basically unchanged, the refractive index, density, and viscosity increased dramatically. From point F2 to E3, both the refractive index and density increased slowly with the moderate increasing of Cl− concentration; nevertheless, the pH values decreased gradually. Figure 5d shows that the pH values increased with the increase in the percentage of alkaline borate and that the solution was basically in the alkaline range.

4. CONCLUSION The solubility data and physicochemical properties of the stable equilibria of the reciprocal quaternary system (Na+, Ca2+//Cl−, borate−H2O) at 288.15 K were experimentally determined using the classic isothermal dissolution method. On the basis of the data obtained, the phase diagrams concerning dry-salt, water-phase, and corresponding physicochemical properties were plotted. Accordingly, the dry-salt phase diagram shows the quaternary system at 288.15 K consists of two invariant points, five univariant curves, and four crystallization zones. The incongruent point F1 and congruent point F2 cosaturated with three salts and one equilibrium solution. The crystallization zone of CaB6O10·5H2O is the largest, and the area of those of Na2B4O7·10H2O, NaCl, and CaCl2·6H2O are decreased in order, demonstrating the lowest solubility of gowerite. Moreover, the physicochemical properties of the system (Na+, Ca2+//Cl−, borate−H2O) at 288.15 K varied regularly with increasing Jänecke index values of J(B4O72−).

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Tel./fax: +86 22-60601156. ORCID

Yafei Guo: 0000-0003-0698-3565 Lingzong Meng: 0000-0002-2904-7000 Shiqiang Wang: 0000-0002-6733-7076 Tianlong Deng: 0000-0002-1728-2943 Funding

Financial support from the National Natural Science Foundation of China (U1607123, U1507112, 21773170, and U1707602) and the Yangtze Scholars and Innovative Research Team of the Chinese University (IRT_17R81) is acknowledged. Notes

The authors declare no competing financial interest.

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REFERENCES

(1) Ishii, T.; Kokaku, H.; Nagai, A.; Nishita, T.; Kakimoto, M. Calcium borate flame retardation system for epoxy molding compounds. Polym. Eng. Sci. 2006, 46, 799−806. G


Cl

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