本文選題：碳酸化分解法 + 片狀氧化鋁��； 參考：《中南大學(xué)》2010年碩士論文

【摘要】： 本文以低濃度鋁酸鈉溶液為原料,利用二氧化碳?xì)怏w進(jìn)行碳酸化分解,通過多種添加劑的相互作用,制備出氫氧化鋁前驅(qū)體,該前驅(qū)體在一定條件下煅燒后得到具有完整六角片狀的氧化鋁粉體。實(shí)驗(yàn)根據(jù)碳酸化分解原理和片狀氧化鋁晶體生長(zhǎng)習(xí)性,考察了各操作參數(shù)對(duì)產(chǎn)物晶型結(jié)構(gòu)的影響。 研究發(fā)現(xiàn),鋁酸鈉溶液苛性比(αK)與苛性堿濃度(NK)對(duì)前驅(qū)體制備有很大影響,NK增大會(huì)降低碳酸化分解效率；但減小NK會(huì)降低擬薄水鋁石向三水鋁石的轉(zhuǎn)化的效率；同時(shí),NK和αK相互制約,影響著反應(yīng)驅(qū)動(dòng)力的大��；傳統(tǒng)碳酸化分解法制備得到的氫氧化鋁呈砂狀,團(tuán)聚嚴(yán)重,SEM檢測(cè)發(fā)現(xiàn),添加硬脂酸作表面活性劑,四氯化鈦、焦磷酸鈉作為晶型向?qū)?得到的前驅(qū)體氫氧化鋁具有良好片狀結(jié)構(gòu),且降低了團(tuán)聚程度；XRD檢測(cè)表明：直接煅燒至1400℃,前驅(qū)體氫氧化鋁仍然不能完全轉(zhuǎn)化為α-Al2O3，向體系中添加氟化鋁,可以明顯降低α-Al2O3的轉(zhuǎn)化溫度。 綜上所述,利用碳酸化分解法制備前驅(qū)體氫氧化鋁合適的條件為：控制鋁酸鈉溶液αK=1.7,NK=100g/L,濃度為2.0mol/L,添加10%(質(zhì)量分?jǐn)?shù),下同)硬脂酸作表面活性劑,5%氟化鋁、3%焦磷酸鈉和3%四氯化鈦?zhàn)骶拖驅(qū)?反應(yīng)氣體二氧化碳與氮?dú)?：1混合,混合氣體流速為250L/h,于45℃水浴條件下進(jìn)行碳酸化分解反應(yīng),pH=12.0反應(yīng)達(dá)到終點(diǎn),過濾洗滌后,加入10%異丁醇于100℃下干燥5h。此條件下得到的前驅(qū)體在1200℃下煅燒5h即可得到平均粒徑為30.13μm,具有明顯六角片狀結(jié)構(gòu),表面光滑,邊緣平整,珠光效果明顯,并且具有較好的耐酸堿能力的α-Al2O3。 采用遮蓋率法和SEM測(cè)量法對(duì)產(chǎn)品的徑厚比進(jìn)行了檢測(cè),得到的徑厚比分別為39.12和42.09。
[Abstract]:In this paper, aluminum hydroxide precursor was prepared from low concentration sodium aluminate solution by carbonation and decomposition of carbon dioxide gas. The precursor was calcined under certain conditions to obtain a complete hexagonal aluminum oxide powder. According to the decomposition principle of carbonation and the growth habit of flake alumina crystal, the effect of operation parameters on the crystal structure of the product was investigated. It was found that the ratio of causticity of sodium aluminate solution (偽 K) and the concentration of caustic soda (NKK) had a great influence on the preparation of precursor. The increase of NK would decrease the efficiency of carbonation decomposition, but the reduction of NK would decrease the conversion efficiency of pseudoboehmite to tribobsite. At the same time, NK and 偽 K restrict each other, which affect the driving force of reaction, the aluminum hydroxide prepared by traditional carbonation decomposition method is sandlike, and the agglomeration serious SEM results show that adding stearic acid as surfactant, titanium tetrachloride, titanium tetrachloride, titanium tetrachloride, titanium tetrachloride, Using sodium pyrophosphate as crystal guide agent, the precursor aluminum hydroxide has a good flake structure, and the agglomeration degree is reduced. The results show that the precursor is calcined directly to 1400 鈩，

本文編號(hào)：1841234