本文選題：氟碳鈰礦 + 拋光粉��； 參考：《成都理工大學(xué)》2015年碩士論文

【摘要】：二氧化鈰是一種應(yīng)用非常廣泛的稀土氧化物,尤其在化學(xué)機(jī)械拋光(CMP)領(lǐng)域中,具有舉足輕重的作用。由于對(duì)高精度光學(xué)透鏡和集成電路化學(xué)機(jī)械拋光的嚴(yán)格要求,越來(lái)越多的注意力集中到了高品位二氧化鈰的制備上來(lái)。目前主要使用硝酸鈰或氯化鈰等鈰鹽作為鈰源,通過(guò)溶膠-凝膠法、水熱法或者沉淀法等化學(xué)合成方法制備二氧化鈰。生產(chǎn)成本高、工藝復(fù)雜,并且對(duì)環(huán)境造成二次污染。如今,以氟碳鈰礦為原材料制備二氧化鈰已經(jīng)成為一個(gè)研究熱點(diǎn)。四川氟碳鈰礦儲(chǔ)量豐富、成分單一、礦粒粗大、易選易冶,主要成分是Ce、La、Pr、Nd等輕稀土元素,為制備二氧化鈰提供了豐富的原材料來(lái)源。本論文以氟碳鈰礦為原材料,通過(guò)碳酸氫鈉焙燒-稀鹽酸浸出工藝制備高品位二氧化鈰,主要進(jìn)行了以下四個(gè)部分內(nèi)容的研究。首先研究了氟碳鈰礦加碳酸氫鈉的焙燒分解機(jī)理,在此基礎(chǔ)上研究了焙燒條件對(duì)Ce氧化率的影響。研究表明:碳酸氫鈉添加量為20%,600 oC焙燒2 h,焙燒產(chǎn)物中Ce的氧化率大于94.50%。其次對(duì)焙燒產(chǎn)物進(jìn)行了水洗除氟的實(shí)驗(yàn)研究,研究表明:液固比為15:1,50 oC水洗1 h,焙燒產(chǎn)物中的NaF完全浸出到水洗液中。再次利用水浸渣進(jìn)行了分離提純制備二氧化鈰的實(shí)驗(yàn)研究,研究結(jié)果表明:按鹽酸浸取-NaOH焙燒-鹽酸浸取法,分離提純得到的二氧化鈰中,二氧化鈰的含量為81.17%,稀土含量為96.99%,Ce的回收率為82.89%。符合稀土拋光粉國(guó)家標(biāo)準(zhǔn)對(duì)拋光粉化學(xué)成分的要求。其中優(yōu)化的鹽酸浸取條件為,固液比1:5,在75 oC下2 mol?L-1 HCl浸出1 h;優(yōu)化的NaOH焙燒條件為,NaOH添加量為30%,500 oC焙燒0.5 h。最后對(duì)制備的二氧化鈰進(jìn)行了表征并對(duì)其懸浮性進(jìn)行了研究。研究結(jié)果表明:500 oC,2 h焙燒得到的二氧化鈰,粒徑大致分布在20~100 nm之間,平均粒徑大約為40 nm左右,為納米級(jí)。500 oC~800 oC焙燒2 h得到的二氧化鈰中,二次粒子的中位徑在0.24~1.56μm范圍內(nèi),符合稀土拋光粉國(guó)家標(biāo)準(zhǔn)對(duì)拋光粉的粒徑要求。焙燒溫度越高,二氧化鈰的懸浮性越差,聚丙烯酸可以很好的改善二氧化鈰的懸浮性。
[Abstract]:Cerium oxide is a widely used rare earth oxide, especially in the field of chemical mechanical polishing (CMP). Due to the strict requirements for high precision optical lenses and chemical mechanical polishing of integrated circuits, more and more attention has been paid to the preparation of high grade cerium oxide. At present, cerium nitrate or cerium chloride is used as cerium source. Cerium dioxide is synthesized by sol-gel method, hydrothermal method or precipitation method. The production cost is high, the process is complex, and it causes secondary pollution to the environment. Nowadays, the preparation of cerium dioxide from fluorocarbon ore has become a research hotspot. Sichuan fluorocarbon cerium ore is rich in reserves, single in composition, coarse in grain size, easy to be selected and easy to smelt. The main composition is the light rare earth elements, such as cerium lae Prande ND and so on, which provide abundant raw materials for the preparation of cerium dioxide. In this paper, high grade cerium dioxide was prepared by sodium bicarbonate roasting and leaching with dilute hydrochloric acid using fluorocarbon-cerium ore as raw material. Firstly, the calcination mechanism of fluorocarbon and sodium bicarbonate was studied, and the effect of calcination conditions on the oxidation rate of ce was studied. The results showed that the oxidation rate of ce in the calcined product was more than 94.50 when the amount of sodium bicarbonate was 20 ~ 600oC for 2 h. Secondly, the fluoride removal from roasted products was studied by water washing. The results showed that NAF from roasted products was completely leached into the washing solution for 1 h. The ratio of liquid to solid was 15: 1 ~ 1 ~ (-1) ~ (50) 鈩，

本文編號(hào)：2046194