本文選題：納米氫氧化鎂 + 活性氧化鎂　； 參考：《華東師范大學(xué)》2015年碩士論文

【摘要】：我國鹵水資源豐富,多以鎂離子形式存在。近來,海水淡化、制鹽工業(yè)和通過鹽湖來提取鉀元素也產(chǎn)生大量鹵水廢液,一定程度上造成污染,所以合理利用鹵水,將其變廢為寶意義重大。納米材料是21世紀(jì)的新型材料,由于具有粒徑小、比表面積大、形貌多樣等特點而在光電、化學(xué)等方面表現(xiàn)出特異性,所以有關(guān)鎂化合物納米材料的生產(chǎn)受到廣泛關(guān)注。納米氫氧化鎂是一種重要的無機材料,由于其受熱分解成氧化鎂和水,可將其作為一種無煙無毒的防燃填充材料,此外它中和能力強,在醫(yī)藥等方面也有廣泛應(yīng)用。高活性氧化鎂粒徑一般小于2000nm,通常檸檬酸活性測定值在25s以下,由于顆粒細(xì)微其光電磁等特性異于一般氧化鎂。在醫(yī)藥上可用作治療腸胃疾病藥品的輔佐添加劑；環(huán)保上可作為高效解離吸附劑,吸附酸性氣體和含氯烴、有機磷的有毒化學(xué)物質(zhì)等。本文采用鹵水-堿法在不同實驗條件下制備納米氫氧化鎂和活性氧化鎂,同時也探索了制備堆積密度大于0.5g/ml的重質(zhì)氧化鎂。主要的研究內(nèi)容有：1.鹵水-燒堿直接沉淀法制備納米氫氧化鎂粉體以鹵水、燒堿為原料制備目標(biāo)粉體氫氧化鎂,制備時考察了反應(yīng)溫度、反應(yīng)時間、濃度、干燥方式等因素對粉體粒度D50(平均粒度,下同)的影響。用激光粒度儀測量不同實驗條件下制得粉體的平均粒度D50,并對粉體進行XRD、SEM和TG-DTG表征分析。最終在最優(yōu)條件下制得純度高、粒度小、疏松分散的片狀納米氫氧化鎂,其厚度約為10nm、直徑約150nm。2.不同條件下鹵水-堿法制備氧化鎂并考察其活性以鹵水、燒堿為原料制備氧化鎂前驅(qū)體,煅燒得氧化鎂后檸檬酸法測其活性。改變反應(yīng)溫度、濃度和干燥方式等考察其與粉體活性的關(guān)系,確定最優(yōu)反應(yīng)條件；分別考察了正向滴加、反向滴加和雙注滴加法對所制備出的氧化鎂活性的影響,以確定滴加方式；最后對產(chǎn)物進行XRD、SEM表征分析。研究發(fā)現(xiàn)：當(dāng)鹵水稍過量,最佳的反應(yīng)條件和煅燒溫度下能夠制備出粒度小、分散性高、表面多孔的片狀活性氧化鎂,其檸檬酸活性檢測(CAA值)約8s。3.鹵水-混堿直接沉淀法制備重質(zhì)氧化鎂以鹵水、燒堿、純堿為原料采用直接沉淀法制備氧化鎂前驅(qū)體,首先分別以純堿、燒堿及二者混合為沉淀劑制備氧化鎂,測出其堆積密度,并進行XRD、SEM表征分析,以判斷出最佳堿性沉淀劑；然后控制混堿的總量一定,通過改變混堿摩爾比、制備時溫度、濃度等條件制備氧化鎂前驅(qū)體,再煅燒制氧化鎂粉體,得目標(biāo)粉體后測出其堆積密度,確定最佳制備條件。研究發(fā)現(xiàn)：純堿、燒堿以摩爾比1：3與鹵水在T=60℃時反應(yīng),850℃下煅燒2.5h得氧化鎂堆積密度最大,約1.527g/ml。
[Abstract]:Brine resources are abundant in China, and most of them exist in the form of magnesium ions. Recently, seawater desalination, salt industry and the extraction of potassium from salt lakes also produce a large amount of brine waste liquid, which causes pollution to a certain extent, so it is of great significance to make rational use of brine and turn it into a treasure. Nanomaterials are new materials in the 21st century. Because of their small particle size, large specific surface area and various morphologies, nanomaterials show specificity in photoelectricity and chemistry, so the production of magnesium nanomaterials has been paid more and more attention. Nanocrystalline magnesium hydroxide is an important inorganic material, which can be used as a kind of smokeless and non-toxic combustion-proof filling material because of its thermal decomposition into magnesium oxide and water. In addition, it has strong neutralization ability and has been widely used in medicine and so on. The particle size of highly active magnesium oxide is generally less than 2000nm, and the determination value of citric acid activity is less than 25s, which is different from that of ordinary magnesium oxide because of its fine photoelectric and magnetic properties. It can be used as adjuvant additive in medicine for treating gastroenteric diseases, environmental protection can be used as high efficient dissociation adsorbent, adsorption of acid gas and chlorinated hydrocarbon, toxic chemicals of organophosphorus and so on. In this paper, nanocrystalline magnesium hydroxide and active magnesium oxide were prepared by brine-alkali method under different experimental conditions. At the same time, the preparation of heavy magnesium oxide with bulk density greater than 0.5g/ml was also explored. The main content of the study is: 1. Magnesium hydroxide nanoparticles were prepared by brine and caustic soda direct precipitation method. The reaction temperature, reaction time, concentration, drying method and other factors on the particle size D50 (average particle size) were investigated during the preparation of magnesium hydroxide, which was prepared from brine and caustic soda. The same as below. The average particle size D50 of the powder was measured by laser particle size analyzer under different experimental conditions. The powder was characterized by XRD SEM and TG-DTG. Finally, the high purity, small particle size and loose dispersion of flake magnesium hydroxide were obtained under the optimum conditions, the thickness of which was about 10 nm and the diameter of magnesium hydroxide was about 150 nm.2. Magnesium oxide was prepared by brine alkali method under different conditions. The activity of magnesium oxide precursor was studied by using brine and caustic soda as raw materials. The activity of magnesium oxide was measured by citric acid method after calcination. The optimum reaction conditions were determined by changing the reaction temperature, concentration and drying method, and the effects of direct drop, reverse drop and double drip addition on the activity of the prepared magnesium oxide were investigated, respectively. Finally, the products were characterized by XRDX SEM. It is found that when the brine is slightly excessive, the best reaction conditions and calcination temperature can be used to prepare the flake active magnesium oxide with small particle size, high dispersion and porous surface. The CAA value of its citric acid activity is about 8s. 3. Preparation of heavy magnesium oxide by direct precipitation of brine, caustic soda and soda, magnesium oxide precursor was prepared by direct precipitation method. First, magnesium oxide was prepared by using soda, caustic soda and their mixture as precipitators, respectively. The bulk density was measured and analyzed by XRDX SEM to determine the best alkaline precipitator, and then the magnesium oxide precursor was prepared by changing the molar ratio of the mixed base, temperature and concentration of the mixed alkali, and then controlling the total amount of the mixed alkali. After calcining the magnesium oxide powder, the stacking density of the target powder was measured and the optimum preparation conditions were determined. The results show that the maximum bulk density of magnesium oxide can be obtained by calcination of soda and caustic soda at 850 鈩，

本文編號：1966313