The Enhancement of Surface Area of Coal Fly Ash /Iron Blast Furnace Slag by Organic Acid

• Main Authors: Shu-Ming Liu, 劉樹明
• Other Authors: Kou-Ching Chang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/74851526494634188848

碩士 === 國立屏東科技大學 === 環境工程與科學系 === 92 === The purpose of this study is to modify Coal Fly Ash (CFA) / Iron Blast Furnace Slag (IBFS) into an absorbent for heavy metal or (in) organic pollutants, by change its recipes and synthesis conditions in order to investigate an optima operation mode for increasing its adsorptive ability. The materials used for this study are CFA from steam power plant and IBFS form China Steel Corp. Either CFA or IBFS contains high amount glassy content of CaO, SiO2 and Al2O3. There are approximate 70 wt% glassy content in CFA, and 95 wt% in IBFS. These Kinds glassy are like nature Pozzolana which are easy to hydrate with Ca(OH)2 solution to form a series of calcium silicate hydrates or calcium aluminate hydrates with large surface area and somewhat mechanical strength. The hydrates are amorphous gels, and possess fiber texture. This study try to use the characteristic of the fiber texture to change its structure into a larger surface area structure by using the addition of organic acids which are Citric acid, Lactic acid and Acetic acid. The procedures in sequence are, 1) to mix CFA/IBFS with Ca(OH)2 and water. 2) to add different concentration of each acid individually. 3) to stir together and at the same time heat the sample from ambient temperature to 70, 80 or 90ºC. 4) to put each sample at a fixed temperature as former an a fixed period. 5) to filter and to dry the synthesized produces. 6) to measure specific surface area of dry produces by air permeability apparatus.The results indicate that, (1)The surface area of without acid is less than those of with acid and the highest surface area is the sample with citric acid.(2)The optima temperature is with Citric Acid at 80ºC, with Lactic Acid at 90ºC, and with Acetic acid at 70ºC.(3)the optima recipes is CFA / IBFS = 3/7 for any kind of acid. Many researcher have reported that it is a technique whatever Bench-Test or Pilot-Scale-Test by utilizing CFA to synthesis an absorbent for the adsorption of SOx from flue gas or for the adsorption of heavy metal from waste water. The success of this study could provide an another choice on the selection of adsorbent, and an another recycling method to promote the additional value of waste utilization.