붕소함유 염수와 간수로부터 고순도 calcium borate를 합성하는 반응에 황산이 미치는 영향 = Effects of Sulfuric Acid on the Synthesis of Highly Pure Calcium Borate in the Boron-Containing Brine and Bittern

국문 초록 (Abstract)

본 연구에서는 붕소함유 인공염수(간수)를 수산화칼슘으로 포화시켜 calcium borate를 합성하는 반응에서, 첨가하는 황산이 미치는 영향을 알아보았다. 다양한 조건(반응온도, 반응시간, 가열반응 후 방랭온도)에서 calcium borate 합성을 시도하였고, 각 조건에서 황산 첨가유무에 따른 calcium borate의 회수율과 순도 변화를 알아보았다. XRD 분석을 통해 황산의 첨가유무에 상관없이 calcium borate(Ca2B2O5·H2O)가 생성되었음을 확인하였고, 황산을 첨가하면 부산물로 황산칼슘(CaSO4·0.5H2O)이 생성되었다. 황산을 첨가하지 않았을 때, 실험한 모든 반응온도와 반응시간 조건에서 calcium borate의 회수율과 순도가 황산을 첨가했을 때보다 더 높았다. 황산을 첨가하면 수산화칼슘의 용해도는 높아지지만, 부산물로 생성되는 황산칼슘이 calcium borate의 생성을 방해하여 그 회수율과 순도가 낮아진다고 판단된다. 본 연구에서는 붕소함유(500 mg-B/L) 인공염수(간수)에 황산을 첨가하지 않고 수산화칼슘으로 포화시켜서 80-105 ℃에서 10분 이내로 가열하여 calcium borate를 합성하였고, 그 회수율과 순도는 각각 최대 80 %, 96 %로 매우 높았다.

다국어 초록 (Multilingual Abstract)

In this study, we investigated the effects of sulfuric acid on the synthesis of calcium borate in the artificial boron-containing brine (bittern) saturated with calcium hydroxide. For the study, we attempted to synthesize calcium borate under various conditions such as reaction temperature, reaction time, and cooling temperature after heating, and then to examine the recovery and purity of the calcium borate according to the presence or absence of sulfuric acid at each condition. The XRD analysis confirmed that, regardless of the presence of sulfuric acid, the calcium borate (Ca2B2O5·H2O) was synthesized, while, in the presence of sulfuric acid, the calcium sulfate (CaSO4·0.5H2O) was produced as a by-product. In all the experiments performed by varying the reaction temperature and time, the recovery and purity of the calcium borate without sulfuric acid were observed higher than those with it. The results indicated that the addition of sulfuric acid increased the solubility of the calcium hydroxide, but the calcium sulfate produced as a by-product could decrease the recovery and purity of the calcium borate by preventing the synthesis. In this study, the artificial boron-containing brine (bittern) (500 mg-B/L) was saturated with calcium hydroxide in the absence of sulfuric acid, and then the solution was heated at 80-105 ℃ for less than 10 minutes to synthesize the calcium borate. The recovery and purity of calcium borate were measured as high as 80 % and 96 %, respectively.

참고문헌 (Reference)

1 Tsai, H. C, "Using pretreated waste oyster shells and microwave hydrothermal treatment to recover boron from concentrated wastewater" 102 : 7802-7806, 2011

2 Irawan, C, "Treatment of boron-containing optoelectronic wastewater by precipitation process" 280 : 146-151, 2011

3 Power P. P., "The chemistry of boron and its speciation in plants" 193 (193): 1-13, 1997

4 Remy, P, "Removal of Boron from Wastewater by Precipitation of a Sparingly Soluble Salt" 24 (24): 105-110, 2004

5 Ismail, I, "Removal of Boron from Bittern Solution of Lake Qarun Water by Electrically Assisted Ion Exchange" 32 (32): 125-136, 2014

6 An, J. W, "Recovery of lithium from Uyuni salar brine" 117 (117): 64-70, 2012

7 Kim, J. S, "Recovery of Lithium and Boron from the Domestic Bittern by an Ion Exchange Method" 30 (30): 600-607, 1992

8 Itakura, T, "Precipitation recovery of boron from wastewater by hydrothermal mineralization" 39 : 2543-2548, 2005

9 Bothe, J. V., "Phase formation in the system CaO-Al2O3-B2O3-H2O at 23 ± 1℃" B (B): 199-210, 1998

10 Bingham, F. T, "Methods of soil analysis, part 2. Chemical and microbiological properties" American Society of Agronomy 435-436, 1982

11 Hobbs, M. Y., "Effect of pH on boron coprecipitation by calcite: Further evidence for nonequilibrium partitioning of trace elements" 63 (63): 1013-1021, 1999

12 최병현, "Colemanite 광물로부터 붕소화합물의 제조에 관한 연구: 붕산제조 및 반응기구(I)" 한국세라믹학회 41 (41): 6-6, 2004

13 Tagliabue, M, "Boron removal from water:needs, challenges and perspectives" 77 : 56-64, 2014

14 Güler, E, "Boron removal from seawater:State-of-the-art review" 356 : 85-93, 2015

15 Alper Erdem Yilmaz, "Boron removal by means of chemical precipitation with calcium hydroxide and calcium borate formation" 한국화학공학회 29 (29): 1382-1387, 2012

16 Tsai, H. C., "Boron removal and recovery from concentrated wastewater using a microwave hydrothermal method" 186 : 1431-1437, 2011

17 Parks, J. L., "Boron in the Environment" 35 : 81-114, 2005

18 Lozano, J. A. F, "A Noble Process for the Production of Multinutrient Phosphatic Base Fertilizers from Seawater Bittern and Phosphoric Acid" 24 (24): 317-320, 1999