• Title/Summary/Keyword: 탄산화율

Search Result 7, Processing Time 0.024 seconds

The Mineral Carbonation Using Steelmaking Reduction Slag (제강 환원슬래그의 광물탄산화)

  • Ryu, Kyoung-Won;Choi, Sang-Hoon
    • Economic and Environmental Geology
    • /
    • v.50 no.1
    • /
    • pp.27-34
    • /
    • 2017
  • Mineral carbonation for the storage of carbon dioxide is a CCS option that provides an alternative for the more widely advocated method of geological storage in underground formation. Carbonation of magnesium- or calcium-based minerals, especially the carbonation of waste materials and industrial by-products is expanding, even though total amounts of the industrial waste are too small to substantially reduce the $CO_2$ emissions. The mineral carbonation was performed with steelmaking reduction slag as starting material. The steelmaking reduction slag dissolution experiments were conducted in the $H_2SO_4$ and $NH_4NO_3$ solution with concentration range of 0.3 to 1 M at $100^{\circ}C$ and $150^{\circ}C$. The hydrothermal treatment was performed to the starting material via a modified direct aqueous carbonation process at the same leaching temperature. The initial pH of the solution was adjusted to 12 and $CO_2$ partial pressure was 1MPa for the carbonation. The carbonation rate after extracting $Ca^^{2+}$ under $NH_4NO_3$ was higher than that under $H_2SO_4$ and the carbonation rates in 1M $NH_4NO_3$ solution at $150^{\circ}C$ was dramatically enhanced about 93%. In this condition well-faceted rhombohedral calcite, and rod or flower-shaped aragonite were appeared together in products. As the concentration of $H_2SO_4$ increased, the formation of gypsum was predominant and the carbonation rate decreased sharply. Therefore it is considered that the selection of the leaching solution which does not affect the starting material is important in the carbonation reaction.

Mineral Carbonation of High Carbon Dioxide Composition Gases Using Wollastonite-distilled Water Suspension (규회석-증류수 현탁액을 이용한 고농도 CO2 가스의 탄산염 광물화)

  • Song, Haejung;Han, Sang-Jun;Wee, Jung-Ho
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.36 no.5
    • /
    • pp.342-351
    • /
    • 2014
  • The present paper investigates the performance of direct wet mineral carbonation technology to fix carbon dioxide ($CO_2$) from relatively high $CO_2$ concentration feeding gas using wollastonite ($CaSiO_3$)-water (and 0.46 M acetic acid) suspension solution. To minimize the energy consumed on the process, the carbonation in this work is carried out at atmospheric pressure and slightly higher room temperature. As a result, carbon fixation is confirmed on the surface of $CaSiO_3$ after carbonation with wollastonite-water suspension solution and its amount is increased according to the $CO_2$ composition in the feeding gas. The leaching and carbonation ratio of wollastonite-water suspension system obtained from the carbonation with 50% of $CO_2$ composition feeding gas is 13.2% and 10.4%, respectively. On the other hand, the performance of wollastonite-acetic acid in the same condition is 63% for leaching and 1.39% for carbonation.

Effect of Carbon Dioxide Pressure on Mineral Carbonation in Acidic Solutions (산성용액에서 이산화탄소의 압력이 광물탄산화에 미치는 영향)

  • Ryu, Kyoung Won;Hong, Seok Jin;Choi, Sang Hoon
    • Economic and Environmental Geology
    • /
    • v.53 no.1
    • /
    • pp.1-9
    • /
    • 2020
  • Magnesium silicate minerals such as serpentine [Mg3Si2O5(OH)4] have a high potential for the sequestration of CO2; thus, their reactivity toward dissolution under CO2-free and CO2-containing conditions in acidic solvents is a critical process with respect to their carbonation reactions. To examine the carbonation efficiency and dissolution mechanism of serpentine, hydrothermal treatment was performed to the starting material via a modified direct aqueous carbonation process at 100 and 150℃. The serpentine dissolution experiments were conducted in H2SO4 solution with concentration range of 0.3-1 M and at a CO2 partial pressure of 3 MPa. The initial pH of the solution was adjusted to 13 for the carbonation process. Under CO2-free and CO2-containing conditions, the carbonation efficiency increased in proportion to the concentration of H2SO4 and the reaction temperature. The leaching rate under CO2-containing conditions was higher than that under CO2-free conditions. This suggests that shows the presence of CO2 affects the carbonation reaction. The leaching and carbonation efficiencies at 150℃ in 1 M H2SO4 solution under CO2-containing conditions were 85 and 84%, respectively. The dissolution rate of Mg was higher than that of Si, such that the Mg : Si ratio of the reacted serpentine decreased from the inner part (approximately 1.5) to the outer part (less than 0.1). The resultant silica-rich layer of the reaction product ultimately changed through the Mg-depleted skeletal phase and the pseudo-serpentine phase to the amorphous silica phase. A passivating silica layer was not observed on the outer surface of the reacted serpentine.

Leaching Property of Coal Fly Ash Using Water as the Solvent and Its Carbonation Performance (석탄 비산재의 물에 대한 침출 특성과 탄산화 성능에 관한 연구)

  • Shin, Jiyoon;Han, Sang-Jun;Wee, Jung-Ho
    • Journal of Korean Society of Environmental Engineers
    • /
    • v.36 no.3
    • /
    • pp.198-205
    • /
    • 2014
  • The present paper investigates the leaching property of coal fly ash (FA) using distilled water as solvent and its performance of mineral carbonation. The highest leaching efficiency is obtained at 100 min after leaching begins and the overall leaching efficiencies of Ca and Na via five consecutive leachings were calculated to be 25.37% and 7.40%, respectively. In addition, because $Ca(OH)_2$ produced during the leaching reacts with $SiO_2$ which is the major component of FA, the Pozzolanic reaction may occur and thus reduces leaching efficiency. Total carbonation capacity of FA by absorbing $CO_2$ into FA leachates is 6.08 mg $CO_2/g$ FA and the contribution of alkali substances such as Ca, Na, Mg and K to this value is calculated to be 5.19 mg $CO_2/g$ FA. Carbonation efficiencies of Ca and Na based on leachates are 85.62% and 77.70%, respectively. On the other hand, the ratios of Ca and Na in raw FA to participate in carbonation are calculated to be 9.04% and 5.26%, respectively.

Carbonation of coal fly ash for construction materials (탄산화 건자재 제조를 위한 석탄 비산회의 탄산화)

  • Park, Jun-Young;Kim, Yoo-Taek;Kim, Hyun-Jung
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.22 no.3
    • /
    • pp.147-151
    • /
    • 2012
  • Carbon dioxide ($CO_2$) could be stored in the form of Ca and Mg compounds including alkaline earth metal by carbonation. The possibility of $CO_2$ storage was tested by using desulfurized ash from fluidized bed type boiler as raw material. Autoclave was used for maintaining the reaction pressure and temperature for the carbonation. The analysis of weight change rate, XRD, and TG/DTA proved that more than 15 % of carbonation rate was obtained under 10 $kgf/cm^2$ and $120^{\circ}C$-10 min.

Properties of non-cement mortars with small addition of alkali activator using fly ash and fused waste slag (석탄회 및 용융폐기물 슬래그에 소량의 알칼리 활성화제를 첨가한 무시멘트 모르타르의 특성)

  • Kim, Yootaek;Lee, Kyongwoo
    • Journal of the Korean Crystal Growth and Crystal Technology
    • /
    • v.25 no.6
    • /
    • pp.257-262
    • /
    • 2015
  • Recently the world wide efforts reduce occurrence of $CO_2$; global warming main reason. The aim of this study is to improve recycling rate of the fly ash (FA) and fused waste slag (FWS) from the power plant and to carbonate under supercritical condition ($40^{\circ}C$, $80kgf/cm^2$ pressure, 60 min) for $CO_2$ fixation. Specimens of mortar with various mixing ratios of FA, FWS (from 100:0 to 20:80 in 5 steps of 20 % reduction each time), distilled water and 3 M NaOH alkali activators were prepared. As a result, the proportion of weight change ratio increases with CaO content, to 12 % after carbonation under the supercritical condition. There is difference of compressive strength between the carbonated and the alkali activator mortar specimens. The stabilization of $CO_2$ fixation through carbonation which could confirm the applicability of the eco-friendly materials without loss of compressive strength.

Calcium Ionization Characteristics and In vitro Bioavailability Derived from Natural Calcium Sources (천연칼슘소재의 이온화 특성 및 In vitro 칼슘 이용률)

  • Jang, Se-Young;Jeong, Yong-Jin
    • Journal of the Korean Society of Food Science and Nutrition
    • /
    • v.42 no.4
    • /
    • pp.497-504
    • /
    • 2013
  • This study examined the characteristics of ionized calcium and in vitro calcium bioavailability rate of calcium from four natural sources: shellfish shell, oyster shell, starfish, egg shell. The levels of dissolved calcium and calcium ions increased at different concentrations of natural calcium (up to 8.0% (w/v)). However, there were insignificant differences in the levels of dissolved calcium and calcium ions between samples at calcium concentrations above 8.0% (w/v). In addition, no significant differences were observed (depending on the calcium source and concentration) with an ionization yield of about 90%. The temperature of the solutions also had little influence on the ionization of calcium. The highest calcium ion content was observed when solutions were left to dissolve calcium for 18 hours. The highest in vitro calcium bioavailability rate achieved among the different calcium solutions was BS (67.3%), with overall bioavailability rates about two times higher than the rates observed in commercially sold calcium supplements and natural calcium. In addition, the in vitro calcium bioavailability rate for ionized calcium in market milk, soy milk, and orange juice was more than twice as high as calcium carbonate. Overall, we expect a high and diverse bioavailability of ionized calcium from natural resources.