熔融悬浮结晶法提纯湿法磷酸

使用熔融悬浮结晶法分离提纯湿法磷酸,研究了全回流稳态操作条件下重力洗涤塔内磷酸的纯化过程,考察了原料质量分数、洗涤塔中搅拌转速等操作条件对塔中产品纯度、杂质质量分数沿塔高分布的影响,并用发汗提纯模型进行了拟合。研究结果表明:采用的悬浮结晶装置对湿法磷酸有良好的分离提纯效果;结晶器进料质量分数、洗涤塔搅拌速率对熔融液中杂质质量分数沿塔高的分布有很大影响,进料质量分数增加,则产品纯度增加,适度的搅拌有助于保证洗涤塔的纯化效率,而过高的搅拌速率对分离提纯效果影响不大。在结晶器H3PO4进料质量分数为84%—86%、洗涤塔搅拌速率为10—20 r/min范围内,产品磷酸纯度可达到食品添加剂的标准,发汗提纯模型能很好地描述稳态操作时塔内的杂质质量分数分布规律,在半对数坐标中,杂质质量分数沿塔高呈线性分布。     

熔融结晶法提纯1-萘酚

从混合萘酚中分离提纯1-萘酚采用熔融结晶技术,通过对降温速率、结晶终温、升温速率及“发汗”终温等因素对粗晶体收率及纯度的影响的综合考虑,经多次反复实验,确定了结晶提纯1-萘酚较佳的工艺参数条件,经过单级结晶1-萘酚的含量由80％上升到了93％。     

利用熔融结晶法进行芴的提纯

以工业芴为原料,实验研究了利用熔融结晶法制备精芴的工艺过程,考察了结晶降温速率、结晶终温、发汗升温速率及发汗终温对产品纯度及收率的影响,得到了利用熔融结晶方法分离提纯芴的优化工艺条件,产品纯度可达97.4%。同时根据实验结果,对芴与2-甲基氧芴两元物系的固液平衡相图进行了推测分析。     

利用熔融结晶法进行苯甲酸的提纯

对苯甲酸的熔融结晶提纯进行了实验研究,探究国内外现有的熔融结晶器与自发明的翅片结晶器和板式结晶器的分离效果。实验结果表明,翅片结晶器和板式结晶器优于传统管式结晶器。并得到翅片结晶器和板式结晶器最优实验条件,使得产品纯度达到99.99%。     

用熔融结晶法分离有机物

熔融结晶是一种分离精制有机物的物理方法。它不用溶剂,仅耗熔解热,设备简单、动力设备少。对易聚合、难精馏、高沸点有机化合物分离与精制具有独特功能。在国外化学工业上已广泛使用,包括萘、肼类、氯苯、硝基苯衍生物、丙烯酸、氯乙酸、甲酚类、脂肪酸等的分离与精制。     

工业生产对苯二胺工艺技术的改进

通过改变投料配比,改进结晶,提纯干燥等工艺过程,产品的收率由原来的70％提高到90％以上,生产周期缩短近半。产品的含量高达99．5％。     

熔融分步结晶提纯L-丙交酯

以实验室制备的粗丙交酯为原料,采用熔融分步结晶法对提纯丙交酯进行了实验研究,考察了熔融分步结晶过程中结晶时间、结晶温差、发汗时间等参数对产品质量分数、结晶率、母液质量分数、组分收率以及提纯能力的影响,同时,对结晶和发汗过程的提纯能力进行了对比研究。结果表明:在给定的原料组成下,较适宜的结晶时间为60 min,结晶温差为20℃,发汗时间为50 min,发汗过程提纯能力是结晶过程的1.77倍。     

区域熔融提纯仪的研制和鉴定

设计并安装了一套区域熔融提纯仪,用苯甲酸和萘对仪器的提纯效果进行了鉴定。提纯后的试样经 DSC 检测,苯甲酸和萘的纯度分别由99.5%和99.3%提高到99.98%。     

熔融结晶法回收硝基氯苯精馏废液的研究

采用熔融结晶法对精馏塔处理过的硝基氯苯废料回收进行了研究。考察了指定进料组成下,降温速率、结晶终温、结晶时间等操作条件对对硝基氯苯(p-NCB)和间硝基氯苯(m-NCB)结晶过程的影响,以及对位结晶与间位结晶的差异。给出了2种典型进料组成的最优操作分离条件:进料质量分数w(p-NCB)=89.31%、w(m-NCB)=10.69%时,降温速率0.049 1℃/min、结晶时间480 min、结晶终温60℃;进料质量分数w(m-NCB)=76.03%、w(p-NCB)=23.97%时,降温速率0.015 8℃/min、结晶时间440 min、结晶终温27℃。实验表明,硝基氯苯间位结晶提纯比对位结晶提纯困难得多,采用实验中获得的最佳分离条件,w(p-NCB)≥90%的原料经单级结晶就可以得到纯度99%以上的产品,w(m-NCB)≥90%的原料通过二级结晶也可得到纯度99%以上的产品,而进料质量分数较低时经过多级结晶也能得到纯度99%以上的产品。     

熔融结晶技术及其应用

介绍了熔融结晶技术的发展现状、原理、特点、装置、优势以及应用。认为熔融结晶技术不需溶剂、耗能小、设备简单，对难精馏、高沸点有机化舍物分离提纯有独特功能。但结晶过程的耦合传质、传热理论研究还不够透彻；应加强结晶器和结晶分离技术的研究，提高分离效率，从而加快熔融结晶精制技术的发展应用。满足工业新材料应用的需要。     

Purification of Acetic Acid Wastewater using Layer Melt Crystallization

Abstract

Ice crystalline layers were prepared from a binary eutectic mixture of acetic acid and water using layer melt crystallization. The crystalline layers were obtained under the conditions of the cooling temperature at 269, 268, and 267 K, the feed compositions of 0.5, 1.0, and 5.0 wt% acetic acid, and the cooling rates of 0.1, 0.5, and 1.0 K/min. After crystallization, sweating operations were carried out for various crystalline layers obtained in crystallization. The effect of sweating on the impurity behavior inside crystalline layer was investigated. The crystalline layer formed in higher growth rate was purified more easily by sweating operations. Effective distribution coefficient in the sweating process was in the range of 0.2 to 0.01, which depended on the crystalline layers formed in crystallization process. Eventually, layer melt crystallization can be used for the treatment of acetic acid wastewater.     

动态熔融结晶工艺

浅谈动态熔融结晶特点及其工艺过程和工艺原理。     

铜熔体的精炼净化技术

本文详细的介绍了铜熔体精炼净化过程中除杂、脱气、脱氧的各种技术现状,分析了铜熔炼所用熔剂的基本要求。     

Purification of Nickel Sulfate by Batch Cooling Crystallization

Cooling crystallization was successfully carried out in a batch cooling crystallizer from impure acidic solutions to recover nickel as nickel sulfate salt with three different cooling rates. The compositions of the solutions included impurities of sodium, magnesium, chloride, and sulfuric acid to mimic industrial nickel electrowinning process solutions. The results show that NiSO₄·6H₂O mainly crystallized, and its solubility and purity decreased with the increase in the mass ratio of chloride to sulfate. Cooling rates did not have a significant influence on crystal purity; however, it did affect the filter cake moisture; lower moisture can be obtained with a lower cooling rate. The sequence of impurity removal efficiency from high to low was Cl > Na > Mg.     

Kinetics of Melt Crystallization of a Sunflower Oil‐Based Polyunsaturated Fatty Acid Mixture

Important parameters like supercooling and cooling rates affecting the melt crystallization of a polyunsaturated fatty acid (PUFA) mixture obtained from sunflower oil were investigated and compared via high‐resolution polarized‐light microscopy. PUFA was thermally characterized in a differential scanning calorimeter and the significant liquid‐solid‐phase transition temperatures determined were then implemented in the development of specific temperature profiles. Analyzed between two glass slides, induction times were found to decrease with low crystallization temperatures and the number of nuclei per unit area increased with higher supercooling and cooling rates. A comparison between the linear crystal growth rates of pure standards of each of the main fatty acids present in the PUFA mixture and the PUFA mixture itself indicated that the latter is much slower than that of each of its pure components.     

用熔融结晶技术提纯人造麝香DDHI

用熔融结晶技术从DDHI混合物中分离提纯人造麝香DDHI,结晶的适宜条件为 :结晶时间2h ,降温速率 4℃ /h ,通氮气 ,发汗时升温速率为 6℃ /h ,发汗时间为 30min。经过二级结晶 ,w(DDHI) =99 2 % ,收率为 6 3 2 %。     

熔融结晶及其耦合技术研究的进展

介绍逐步冻凝熔融结晶过程和悬浮熔融结晶过程以及各自特点,综述了近年来新型熔融结晶技术与设备的应用研究进展;着重介绍了耦合技术在熔融结晶过程中的应用研究动态;最后展望了熔融结晶技术与设备的发展趋势与方向。     

溶析结晶提纯阿维菌素

[目的]工业中要通过多次重结晶提纯阿维菌素才能得到纯度较高的产品,生产成本大.提出阿维菌素提纯的溶析结晶工艺,减少操作成本.[方法]通过高效液相色谱法和显微镜观察法考察不同溶剂和溶析剂对产品纯度、杂质含量以及产品晶习的影响.[结果]通过1次溶析结晶产品B1纯度可以达到95％以上.得到的产品一般是粒状或者棱柱状.[结论]乙酸乙酯为溶剂、乙醇为溶析剂得到的产品B1纯度最高,而丙酮作溶剂、水为溶析剂对某些杂质有更好的去除效果.溶析结晶得到的产品一般是粒状或者棱柱状,相对冷却结晶得到的针状晶体有利于后续过滤、洗涤、干燥等过程.