【摘要】：近年來,氯化法鈦白越來越受到國家的重視,但是我國在氯化法鈦白生產(chǎn)中仍存在無法獲得穩(wěn)定的高品質(zhì)人造金紅石原料的問題。原料問題已經(jīng)成為我國鈦工業(yè)發(fā)展的瓶頸,要擺脫對進口礦的依賴,必須研究出適合我國鈦鐵礦為原料制備高品質(zhì)人造金紅石的生產(chǎn)技術(shù)。鹽酸浸出法不僅可以有效的去除鈦鐵礦中的鐵鈣鎂等雜質(zhì),獲得高品質(zhì)的人造金紅石,而且鹽酸可以循環(huán)使用,被世界各大生產(chǎn)廠家所采用。本論文圍繞鹽酸浸出云南鈦精礦制備人造金紅石進行了大量的理論分析和試驗研究。云南鈦精礦原礦直接浸出時反應(yīng)活性差,預(yù)氧化和預(yù)還原焙燒均可提高反應(yīng)活性,但預(yù)還原礦和原礦浸出的粉化率均較高(75μm下的產(chǎn)品占30~40%),而預(yù)氧化礦浸出的粉化率較低(75μm下的產(chǎn)品少于5%)。采用鹽酸常壓浸出工藝時,所需鹽酸濃度較高(26%),浸出時間較長(一般至少需要7h),浸出產(chǎn)品TiO2品位低于91%。采用加壓浸出工藝時,可以降低鹽酸濃度,縮短浸出時間。實驗表明,采用一段加壓浸出工藝時,使用20%的鹽酸,浸出產(chǎn)品TiO2品位穩(wěn)定在92%左右,但液固比較大(8:1),并且浸出濾液中酸濃度較高(12~13%),而鐵離子濃度較低(44g/L),不利于廢酸回收。采用鹽酸兩段加壓浸出工藝,第一段利用第二段浸出液浸出,第二段采用20%的新酸,兩段液固比均為5:1、浸出溫度140℃、浸出壓力0.175MPa、每段浸出時間4h,既可以獲得高品位的人造金紅石(TiO2品位可達93%),又可以降低液固比,降低浸出母液中的酸濃度(7%左右)和提高浸出母液中的鐵離子濃度(75g/L)。鹽酸浸出云南鈦精礦原礦和氧化礦均受內(nèi)擴散控制,原礦和氧化礦常壓浸出活化能分別為為62.45kJ/mol和55.21kJ/mol,氧化礦加壓浸出活化能為24.64kJ/mol。針對鹽酸浸出云南鈦精礦產(chǎn)生的粉化現(xiàn)象,通過對原料和浸出產(chǎn)物的分析,以及鈦的溶解與水解規(guī)律的總結(jié),提出了一種鹽酸浸出云南鈦精礦粉化控制機制。在浸出方式一定的條件下,降低粉化主要采用降低均相成核、增大異相形核水解的方法,使得礦粒不易破碎,降低以細小礦粒為異相核心的水解是降低粉化的關(guān)鍵。原礦浸出時,反應(yīng)活性差,水解開始時間長。還原礦浸出時,大量的晶體和小顆粒礦被粉碎,水解很大一部分發(fā)生在這種小顆粒礦上,造成浸出產(chǎn)物細化。預(yù)氧化焙燒后的鈦精礦礦粒強度較高,大量金紅石微晶的出現(xiàn)降低了異相形核水解的自由能,浸出時以金紅石微晶為核心進行水解,水解粒子呈團狀逐漸向礦粒內(nèi)部生長,抗粉碎強度較高,使得浸出產(chǎn)物粒度較大。
[Abstract]:In recent years, chlorination titanium dioxide has been paid more and more attention by the state, but there is still a problem that stable high quality artificial rutile raw materials can not be obtained in the production of chlorination titanium dioxide in our country. The problem of raw materials has become the bottleneck of the development of titanium industry in China. In order to get rid of the dependence on imported minerals, it is necessary to develop a production technology suitable for the preparation of high quality artificial rutile from ilmenite in China. Hydrochloric acid leaching method can not only effectively remove iron, calcium, magnesium and other impurities from ilmenite, but also obtain high quality artificial rutile, and hydrochloric acid can be recycled and adopted by major manufacturers in the world. In this paper, a large number of theoretical analysis and experimental studies have been carried out on the preparation of artificial rutile from Yunnan titanium concentrate by hydrochloric acid leaching. The reaction activity of Yunnan titanium concentrate is poor when the raw ore is directly leached, and both pre-oxidation and pre-reduction roasting can improve the reaction activity, but the pulverized rate of pre-reduction ore and raw ore leaching is higher (the product at 75 渭 m accounts for 30 鈮，

本文編號：2477710