本文選題：水鹵鎂石　切入點(diǎn)：二水氯化鎂　出處：《青海師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：我國(guó)鎂資源豐富,尤其是青藏高原蘊(yùn)藏著巨大的鎂鹽資源。以青海察爾汗鹽湖為例,開發(fā)鈉鹽和鉀鹽之后的廢料老鹵,其主要成分為六水氯化鎂。對(duì)老鹵中的鎂進(jìn)行利用不僅能解決鹽湖中廢物污染的問(wèn)題,而且有利于鹽湖中微量元素的開發(fā),達(dá)到“變廢為寶”的目的。由六水氯化鎂制備無(wú)水氯化鎂,是電解法冶煉金屬鎂的關(guān)鍵技術(shù)�，F(xiàn)有的無(wú)水氯化鎂制備工藝,一類是通入酸性保護(hù)性氣體(如氯氣和氯化氫)除水,此工藝對(duì)設(shè)備的腐蝕嚴(yán)重;另一類在水溶液中通入氨氣,氨氣的絡(luò)合能力強(qiáng)于水的絡(luò)合能力,替代結(jié)晶水,形成六氨氯化鎂,再進(jìn)一步脫氨制備無(wú)水氯化鎂,此工藝在水體系中進(jìn)行,產(chǎn)物中殘余水較多。本論文使用有機(jī)體系,避免水體系中殘余水分的問(wèn)題,采用乙酸酐法除去六水氯化鎂中的結(jié)晶水。六水氯化鎂中的結(jié)晶水分為兩類,四個(gè)分子間的結(jié)晶水和兩個(gè)分子內(nèi)的結(jié)晶水,分子間的結(jié)晶水較易脫去,分子內(nèi)的結(jié)晶水較難脫去,按照脫去結(jié)晶水的難易程度,本論文的主要內(nèi)容分為兩個(gè)部分。第一部分,使用乙酸和乙酸酐體系,利用乙酸酐除去六水氯化鎂中分子間的四個(gè)結(jié)晶水,制備二水氯化鎂。實(shí)驗(yàn)結(jié)果顯示:氯化鎂和乙酸酐的物質(zhì)的量之比為1:9,回流時(shí)間為4h,旋蒸油浴溫度105℃,旋蒸時(shí)間為2h,產(chǎn)物中氯化鎂和結(jié)晶水的物質(zhì)的量之比為1:2.0031。第二部分,采用乙酸、乙酸酐和N,N-二甲基甲酰胺體系。首先,加大回流時(shí)間,發(fā)現(xiàn)產(chǎn)物中結(jié)晶水在逐漸減少,但是,回流時(shí)間過(guò)長(zhǎng),沒(méi)有現(xiàn)實(shí)意義。其次,采用具有絡(luò)合作用的物質(zhì)做催化劑,降低乙酸酐法除去六水氯化鎂分子內(nèi)結(jié)晶水的難度,制備無(wú)水氯化鎂。按照催化劑的性質(zhì)不同,催化劑分為堿性、中性和酸性。堿性催化劑為三乙胺和乙二胺四乙酸二鈉,中性催化劑為乙酸銨和氯化銨,酸性催化劑為檸檬酸、琥珀酸和草酸。實(shí)驗(yàn)結(jié)果顯示:試驗(yàn)選取乙酸酐和草酸作為混合催化劑,二者的物質(zhì)的量之比為1:1,回流24h,滴加乙酸酐的速度為1mL/20min,旋蒸油浴溫度為105℃,旋蒸時(shí)間為2h,得到產(chǎn)品。與無(wú)水氯化鎂對(duì)比,產(chǎn)物中的氯化鎂和結(jié)晶水的物質(zhì)的量之比為1:0.0177,水的質(zhì)量分?jǐn)?shù)為3.3‰。
[Abstract]:China is rich in magnesium resources, especially in the Qinghai-Tibet Plateau, where there is a huge amount of magnesium salt. Taking the Qarhan Salt Lake in Qinghai as an example, the waste materials after the development of sodium salt and potassium salt are old brine. The main component is magnesium chloride hexahydrate. The utilization of magnesium in the old brine can not only solve the problem of waste pollution in salt lake, but also benefit the development of trace elements in salt lake. The preparation of anhydrous magnesium chloride from magnesium chloride hexahydrate is the key technology of smelting magnesium metal by electrolysis. One is the removal of water through acidic protective gases (such as chlorine and hydrogen chloride), which corrodes the equipment seriously; and the other is the introduction of ammonia in aqueous solution, which has a stronger complexing capacity than water, replacing crystalline water. Magnesium hexamethylammonium chloride is formed and anhydrous magnesium chloride is prepared by further deamination. This process is carried out in water system, and the residual water in the product is more. In this paper, organic system is used to avoid the problem of residual water in water system. The crystalline water in magnesium chloride hexahydrate is removed by acetic anhydride method. The crystalline water in magnesium chloride hexahydrate is divided into two categories: four intermolecular crystalline water and two intramolecular crystalline water, and the intermolecular crystalline water is easy to be removed. The intramolecular crystalline water is difficult to be removed. According to the degree of difficulty in removing the crystalline water, the main content of this paper is divided into two parts: the first part, using acetic acid and acetic anhydride system, Magnesium chloride dihydrate was prepared by removing four crystalline water between molecules in magnesium chloride hexahydrate by acetic anhydride. The experimental results showed that the ratio of magnesium chloride to acetic anhydride was 1: 9, the reflux time was 4 h, and the spinning oil bath temperature was 105 鈩，

本文編號(hào)：1618588