本文關(guān)鍵詞： 稀土 萃取 氨氮廢水 氯化銨分解 硫酸鎂　出處：《江西理工大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：本文針對稀土萃取分離過程氨氮廢水治理的難題,結(jié)合課題組前期關(guān)于離子型稀土礦無氨浸礦的研究成果,設(shè)計出稀土分離過程中氨氮內(nèi)循環(huán)濃縮—堿解造氨—硫酸酸化制鹽酸治廢增效的工藝路線,并對創(chuàng)新工藝各主要環(huán)節(jié)進行了較為系統(tǒng)的研究。實驗發(fā)現(xiàn),常溫下氯化銨在稀土溶液中的溶解度隨稀土離子濃度的增大而減小,隨稀土元素原子序數(shù)增大而減小;氯化銨濃度達到飽和狀態(tài)下,溶液的運動粘度值隨原子序數(shù)的增大而增大;氯化銨的濃度不影響稀土萃取時油/水分相,即使在氯化銨飽和狀態(tài)下,萃取過程仍未發(fā)生乳化和分相困難等問題。萃取實驗表明,氯化銨飽和狀態(tài)下稀土的萃取容量和萃取分離系數(shù)與常規(guī)工藝相比,結(jié)果相近,輕稀土的萃取容量比重稀土小;輕稀土的分離系數(shù)隨料液酸度的減小而增大,重稀土恰好相反;另外,反萃酸中含飽和氯化銨對反萃過程無影響,輕稀土的二級反萃率達到98%以上,重稀土達到80%左右。堿解實驗表明,氫氧化鎂比較適合做氯化銨的分解介質(zhì),堿解反應(yīng)須在沸騰(103℃左右)下進行,最優(yōu)條件為溫度130℃,氫氧化鎂過量15%;一定的真空度對反應(yīng)有促進作用。硫酸酸化實驗表明,在一定范圍內(nèi),溫度、真空度和濃硫酸的量均對硫酸化反應(yīng)起促進作用,較優(yōu)工藝條件為:硫酸過量15%,溫度130℃,真空度為0.05MPa;酸化產(chǎn)物通過XRD分析發(fā)現(xiàn)為一水硫酸鎂,并非硫酸氫鎂。本研究獲得的一水硫酸鎂中氯含量超過了要求的1%,可利用乙醇的吸水性重結(jié)晶提純,在常溫25℃下,p H值控制在1.5以上,硫酸鎂初始濃度為1.5mol/L,乙醇的加入量與硫酸鎂溶液量的比為1:1(體積),硫酸鎂的析出率能達到85%以上,而且氯離子含量小于1%。
[Abstract]:This paper aims at the difficult problem of ammonia nitrogen wastewater treatment in rare earth extraction and separation process, combined with the previous research results of ion rare earth ore without ammonia leaching. The process route of ammonia nitrogen internal circulation concentration, alkali hydrolysis, ammonia making and sulfuric acid acidification to produce hydrochloric acid to control waste and increase efficiency in the process of separation of rare earth elements was designed, and the main links of the innovative process were studied systematically, and the experimental results were found. The solubility of ammonium chloride in rare earth solution decreases with the increase of the concentration of rare earth ions and decreases with the increase of atomic number of rare earth elements at room temperature. When the concentration of ammonium chloride reaches saturation, the kinematic viscosity of the solution increases with the increase of atomic number. The concentration of ammonium chloride does not affect the oil / water phase in rare earth extraction, even in the saturated state of ammonium chloride, the extraction process is not emulsified and difficult to separate. The extraction capacity and extraction separation coefficient of rare earth in saturated state of ammonium chloride are similar to those of conventional process, and the specific gravity of rare earth is smaller than that of light rare earth. The separation coefficient of light rare earth increases with the decrease of feed acidity, but the heavy rare earth is opposite. In addition, saturated ammonium chloride in the stripping acid has no effect on the stripping process. The secondary stripping rate of light rare earth is more than 98%, and the heavy rare earth is about 80%. The alkali hydrolysis experiment shows that the secondary stripping rate of light rare earth is more than 98% and that of heavy rare earth is about 80%. Magnesium hydroxide is suitable for the decomposition of ammonium chloride. The alkali hydrolysis should be carried out at boiling temperature of 103 鈩，

本文編號：1475641