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알루미늄 블랙 드로스로부터 산화 환원반응을 이용한 고순도 알파 알루미나의 제조
신의섭,안응모,이수정,오오츠키 치카라,김윤종,조성백,Shin, Eui-Sup,An, Eung-Mo,Lee, Su-Jeong,Ohtsuki, Chikara,Kim, Yun-Jong,Cho, Sung-Baek 한국재료학회 2012 한국재료학회지 Vol.22 No.9
We investigate the effects of redox reaction on preparation of high purity ${\alpha}$-alumina from selectively ground aluminum dross. Preparation procedure of the ${\alpha}$-alumina from the aluminum dross has four steps: i) selective crushing and grinding, ii) leaching process, iii) redox reaction, and iv) precipitation reaction under controlled pH. Aluminum dross supplied from a smelter was ground to separate metallic aluminum. After the separation, the recovered particles were treated with hydrochloric acid(HCl) to leach aluminum as aluminum chloride solution. Then, the aluminum chloride solution was applied to a redox reaction with hydrogen peroxide($H_2O_2$). The pH value of the solution was controlled by addition of ammonia to obtain aluminum hydroxide and to remove other impurities. Then, the obtained aluminum hydroxide was dried at $60^{\circ}C$ and heat-treated at $1300^{\circ}C$ to form ${\alpha}$-alumina. Aluminum dross was found to contain a complex mixture of aluminum metal, aluminum oxide, aluminum nitride, and spinel compounds. Regardless of introduction of the redox reaction, both of the sintered products are composed mainly of ${\alpha}$-alumina. There were fewer impurities in the solution subject to the redox reaction than there were in the solution that was not subject to the redox reaction. The impurities were precipitated by pH control with ammonia solution, and then removed. We can obtain aluminum hydroxide with high purity through control of pH after the redox reaction. Thus, pH control brings a synthesis of ${\alpha}$-alumina with fewer impurities after the redox reaction. Consequently, high purity ${\alpha}$-alumina from aluminum dross can be fabricated through the process by redox reaction.
신의섭,유창식,김대동,윤상남,김진천 대한대장항문학회 2008 Annals of Coloproctolgy Vol.24 No.4
Purpose: The aim of this study was to analyze the risk factors of pouch failure after a restorative proctocolectomy. Methods: A restorative proctocolectomy was performed in 169 patients between November 1989 and May 2007. A retrospective review was done for postoperative complications and follow-up results of pouch failure, and the risk factors of pouch failure were analyzed. Pouch failure was defined as having occurred when a permanent ileostomy was constructed, regardless of pouch removal. The median follow-up was 48 (3∼155) months. Results: Among the 169 cases, 86 cases involved ulcerative colitis (UC group), 70 cases involved familial adenomatous polyposis or attenuated adenomatous polyposis coli (FAP group), and the remaining 13 involved hereditary nonpolyposis colorectal cancer or synchronous colon and rectal caner (CRC group). The sex ratios and the incidences of comorbidity were not significantly different between the groups, but the mean ages were. Complications occurred in 61 patients (36.1%): pelvic sepsis (28 cases), pouchitis (23 cases), desmoid tumor (12 cases), wound infection (10 cases), and anastomosis stricture (4 cases). The 5-year cumulative rate of pouch failure was 9.8%. Presence of a desmoid tumor, pelvic sepsis, and anastomosis stricture were risk factors of pouch failure. Conclusions: The cumulative pouch failure rate after a restorative proctocolectomy was 9.8% for 5 years, and pouch failure was associated with the presence of a desmoid tumor, pelvic sepsis, and anastomosis stricture.