流化床氣相水解制備高純二氧化鈦

趙玉仲，孫建軍，李軍，朱慶山

（1中國(guó)科學(xué)院過程工程研究所，多相復(fù)雜系統(tǒng)國(guó)家重點(diǎn)實(shí)驗(yàn)室，北京 100190；2北京化工大學(xué)化學(xué)工程學(xué)院，北京 100029）

流化床氣相水解制備高純二氧化鈦

趙玉仲1,2，孫建軍2，李軍1，朱慶山1

（1中國(guó)科學(xué)院過程工程研究所，多相復(fù)雜系統(tǒng)國(guó)家重點(diǎn)實(shí)驗(yàn)室，北京 100190；2北京化工大學(xué)化學(xué)工程學(xué)院，北京 100029）

針對(duì)TiCl4氣相水解制備TiO2粉體存在Cl含量高的問題，開展了流化床TiCl4氣相水解制備高純TiO2。系統(tǒng)地研究了反應(yīng)條件、煅燒后處理對(duì)TiO2粉體的純度、形貌、晶型、比表面積的影響。結(jié)果表明，TiO2內(nèi)部結(jié)構(gòu)和晶型的轉(zhuǎn)變有利于Cl的脫除；提高煅燒溫度使TiO2的內(nèi)部結(jié)構(gòu)由多孔疏松向致密結(jié)構(gòu)轉(zhuǎn)變，晶型結(jié)構(gòu)由銳鈦礦相向金紅石相轉(zhuǎn)變，從而有利于提高Cl的脫除率；與空氣煅燒比較，水蒸氣氣氛下的脫氯效率明顯提高，歸因于水蒸氣與TiO2顆粒內(nèi)殘余的多羥基氯化物進(jìn)一步反應(yīng)；氫氣氣氛下可進(jìn)一步提高Cl的脫除率，800℃煅燒2 h后Cl的脫除率達(dá)到95%，主要?dú)w因于氫氣還原TiO2使其晶型結(jié)構(gòu)發(fā)生轉(zhuǎn)變。

流化床；水解；二氧化鈦；超細(xì)粉體；團(tuán)聚

Abstract:Synthesis of high purity TiO2powder by fluidized gas hydrolysis method is investigated.To tackle the problem of high Cl content remained in the TiO2powder,the hydrolysis reaction conditions and subsequently calcination at air,steam and H2are mainly investigated for dechlorination.The results show that the structure and phase transition of TiO2are two key factors that affect the efficiency of dechlorination.With the increase of the calcination temperature,the internal structure of TiO2is changed from porous to dense structure,and the crystalline structure is transformed from anatase to rutile.The structure and phase transition of TiO2are beneficial to increasing the removal rate of Cl.Compared with the air calcination,the dechlorination efficiency in water vapor atmosphere is obviously improved,which is attributed to the further reaction of water vapor and the multi hydroxyl chloride in the TiO2particles.Compared with air and steam calcination,the removal rate of Cl can be further improved up to 95% under the atmosphere of hydrogen at 800℃ for 2h,which is mainly attributed to the reduction of TiO2structure by hydrogen reduction.

Key words:fluidized-bed; hydrolysis; TiO2; ultrafine powders; agglomeration

引 言

高純二氧化鈦具有優(yōu)良的光、電和力學(xué)特性，是制造硬質(zhì)合金、熱敏電阻、功能陶瓷、化妝品、顏料等工業(yè)的重要基礎(chǔ)原料[1]，同時(shí)也可作為重要催化劑載體應(yīng)用于脫硫脫硝、光電轉(zhuǎn)化等催化過程[2-3]。目前，作為顏料用高純二氧化鈦時(shí)，要求其具有TiO2純度高和雜質(zhì)含量低等化學(xué)特性。此外，電子級(jí)高純二氧化鈦還對(duì)二氧化鈦的形狀、粒度大小等物理特性提出了具體指標(biāo)。……