Phase Diagram for the Na2SO4鈥揘aOH鈥揌2O System and Na2SO4 Solubility in Sodium Aluminate Solution with Caustic Ratios of 12 and 15 at 80 掳C

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• 作者：Aijuan Ding ; Yuejiao Wang ; Shuhua Ma ; Shili Zheng ; Fen Guo
• 刊名：Journal of Chemical & Engineering Data
• 出版年：2013
• 出版时间：April 11, 2013
• 年：2013
• 卷：58
• 期：4
• 页码：964-968
• 全文大小：239K
• 年卷期：v.58,no.4(April 11, 2013)
• ISSN：1520-5134

文摘

The phase diagram for the Na₂SO₄鈥揘aOH鈥揌₂O system and solubility data for Na₂SO₄ in sodium aluminate solution with Na₂O to Al₂O₃ ratios (caustic ratios) of 12 and 15 were studied in the full alkali concentration region at 80 掳C. The contents of Al and Na in the solution were analyzed by means of inductively coupled atomic plasma emission spectrometry (ICP-OES). The sulfur content was determined using ion chromatography (IC) and the ethylenediaminetetraacetic acid (EDTA) volumetric method. The phases of the equilibrium solids were identified via X-ray diffraction (XRD) as well as Schreinemaker鈥檚 method. The results showed that the Na₂SO₄ solubility declines as the concentration of NaOH in the ternary system increases. At a NaOH concentration exceeding 32.96 % (mass percent), the Na₂SO₄ solubility is lower than 1.13 %. For this system, the corresponding equilibrium solid phase was identified as anhydrous sodium sulfate (Na₂SO₄) and sodium hydroxide (NaOH). The Na₂SO₄ solubility in the quaternary system approximates the values obtained in the Na₂SO₄鈥揘aOH鈥揌₂O system. At NaOH concentrations higher than 30.68 % and 30.76 % the Na₂SO₄ solubility values in the sodium aluminate solution with caustic ratios of 12 and 15 are lower than 1.03 % and 1.05 %, respectively.