本文選題：稀土分離　切入點：氯化物廢水　出處：《南昌大學(xué)》2015年碩士論文

【摘要】：稀土萃取分離過程可簡單看成是消耗酸堿并產(chǎn)生大量鹽的過程,也是稀土分離廠污染物的主要來源。因此,如何回收利用氯化物廢水是稀土企業(yè)減排的主要任務(wù)。本文針對高濃度氯化銨(鈉)廢水的綜合利用要求,開展了硫酸與氯化物反應(yīng)制取鹽酸和復(fù)合硫酸鹽的小試和工業(yè)化試驗研究,并對復(fù)合硫酸鹽在離子吸附型稀土的浸取性能進行了評價。具體成果有:分別研究了硫酸與氯化鈉和氯化銨廢水反應(yīng)制取鹽酸和復(fù)合硫酸鹽的工藝條件(加酸比、溫度、時間和壓力)對產(chǎn)酸濃度、氯化物轉(zhuǎn)化率和復(fù)合硫酸鹽組成的影響。結(jié)果表明:隨著加酸比n(H+):n(Cl-)的提高,氯化物的轉(zhuǎn)化率提高,而在加酸比固定的條件下,隨氯化物鹽濃度的提高,蒸出鹽酸的濃度增大,但其鹽酸蒸出摩爾數(shù)與加入氫離子摩爾數(shù)的比值基本不變,而且在減壓條件下,可以使鹽酸蒸出率比常壓高出7%左右;當(dāng)氯化物濃度在4mol/L以上時,蒸出鹽酸的濃度均比鹽濃度高�？芍苯佑米飨⊥凛腿》蛛x中的洗酸和反酸。蒸出鹽酸后的復(fù)合硫酸鹽組成與加酸比直接相關(guān),當(dāng)加酸比高于1.8時,主要產(chǎn)物為硫酸氫銨(鈉);加酸比為1.6左右時主要為硫酸氫三銨;加酸比低于1.4時,還有未轉(zhuǎn)化完全的氯化物。所得復(fù)合硫酸鹽均可用于離子吸附型稀土的浸出,而且可以替代硫酸用作稀土碳銨沉淀母液回收使用時的pH調(diào)節(jié)劑和銨離子補充劑。與此同時,還研究了使用酸性硫酸銨或硫酸鋁溶液對離子吸附型稀土的浸取,以提高難浸稀土的浸出,并使浸出的鋁雜質(zhì)能用于循環(huán)浸礦并穩(wěn)定在尾礦中。其方法是利用復(fù)合硫酸鹽來溶解礦山預(yù)處理渣,使稀土和大部分鋁溶解進入溶液,用萃取法回收稀土后的萃余液返回用于離子吸附型稀土的第二階段浸取,使難浸稀土和尾礦中的銨進入溶液而得到進一步的回收利用,再用石灰水護尾,使大部分鋁保存在尾礦中。
[Abstract]:The process of rare earth extraction and separation can be regarded as the process of consuming acid and alkali and producing a large amount of salt, and is also the main source of pollutants in rare earth separation plant. How to recover and utilize chloride wastewater is the main task of rare earth enterprises to reduce emissions. This paper aims at the comprehensive utilization requirements of high concentration ammonium chloride (sodium chloride) wastewater. Pilot and industrial studies on the preparation of hydrochloric acid and complex sulfate by reaction of sulfuric acid with chloride were carried out, The leaching performance of complex sulfate in ion adsorbed rare earths was evaluated. The specific results are as follows: the technological conditions of the reaction of sulfuric acid with sodium chloride and ammonium chloride wastewater to produce hydrochloric acid and compound sulfate (acid addition ratio, temperature, etc.). The effect of time and pressure on the concentration of acid production, the conversion rate of chloride and the composition of compound sulfate. The results showed that the conversion of chloride increased with the increase of acid addition ratio, and the conversion rate of chloride increased when the acid ratio was fixed. With the increase of chloride concentration, the concentration of hydrochloric acid increased, but the ratio of the number of hydrochloric acid vaporized to the molar number of hydrogen ion was almost unchanged, and under the condition of decompression, the evaporation rate of hydrochloric acid was about 7% higher than that of normal pressure. When the concentration of chloride is above 4mol/L, the concentration of HCl is higher than that of salt. It can be directly used as washing acid and regurgitating acid in the extraction separation of rare earth. The composition of compound sulfate after distilling out of HCl is directly related to the ratio of adding acid to acid, and the ratio of adding acid to acid is higher than 1.8. The main products are ammonium hydrogen sulfate (Na ~ (2 +)) (Na ~ (2 +)); when the ratio of acid to acid is about 1.6 or so, there is also an incomplete chloride when the ratio of acid to acid is less than 1.4. The resulting compound sulfate can be used in the leaching of ion-adsorbed rare earths. It can be used as pH regulator and ammonium ion supplement in the recovery of ammonium carbonate precipitation mother liquor. At the same time, the leaching of ion adsorbed rare earths by acid ammonium sulfate or aluminum sulfate solution has been studied. In order to improve the leaching of refractory rare earths, and to make the leached aluminum impurities can be used in circulating leaching and stabilizing in tailings, the method is to dissolve the pretreatment slag of mine by using compound sulfate, so that the rare earth and most of aluminum can be dissolved into the solution. The residual solution of rare earths recovered by extraction is returned to the second stage of leaching of ion-adsorbed rare earths, so that the ammonium in refractory rare earths and tailings can be further recovered and used to protect the tail with lime-water. Keep most of the aluminum in tailings.
【學(xué)位授予單位】：南昌大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X756

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