尿素氯化铵的稳定性及提纯工艺研究

发布时间：2018-06-22 21:44

本文选题：尿素氯化铵 + 密度分选法　；参考：《山西师范大学》2017年硕士论文

【摘要】：我们研究小组发现并提出了一种新的、简单的、在工业规模上合成尿素氯化铵(U-AC)共晶的方法-固相微孔道法。本文主要研究了专门针对固相法生长尿素氯化铵共晶的一种提纯工艺,旨在分离、提纯得到纯净的U-AC,便于以后的研究以及性质测试。U-AC的分离提纯工艺由一系列操作构成,主要分为两个部分:第一部分通过重结晶得到尿素氯化铵的粗产物;第二部分利用密度分选法对重结晶产物进一步分离提纯。最后,将此提纯工艺在工业规模上大试。首先,由于尿素氯化铵共晶是生长在复合肥颗粒中的,通过风选法将尿素氯化铵共晶从复合肥颗粒中初步分离出来,然后通过溶解、过滤、氨基酸辅助重结晶得到尿素氯化铵粗产物。其中,通过比较添加抑制剂氨基酸前后,尿素氯化铵的重结晶产率,选出了对尿素氯化铵分解具有抑制作用的氨基酸,并对抑制剂的浓度、重结晶的温度进行了选择。最后分析了L-半胱氨酸抑制尿素氯化铵分解的机理。通过测试,L-半胱氨酸辅助U-AC重结晶与直接重结晶U-AC相比,产率从52.41%提升到了78.26%,具有显著的效果。其次,由于尿素氯化铵易于分解,重结晶产物仍然是一个混合物其中含有尿素、氯化铵等杂质。通过密度分离法,以苯和四氯化碳为分选介质依次将尿素和氯化铵除去。密度分选法需要两次,第一次分选苯与四氯化碳的体积比为1:2,此时,尿素漂浮在介质表面,氯化铵与尿素氯化铵沉在下层。将第一次的下层的物质再进行第二次分选以达到除去氯化铵的目的,此时苯与四氯化碳的体积为1:4.5,在此比例的介质中,尿素氯化铵漂浮在介质的表面,而氯化铵沉在介质的底部。每次分离后可以通过过滤的方法得到目标物质。最后,得到目标化合物经XRD鉴定,氯和氮含量的测定与标准值对比。结果表明,U-AC纯度大大地提高。最后,将提纯方法应用于实际大规模提纯过程中,并对尿素氯化铵的性质进行了研究,发现尿素氯化铵溶液具有耐火性,可以用作耐火材料。
[Abstract]:Our team found and proposed a new and simple method for the synthesis of urea-ammonium chloride (U-AC) eutectic on an industrial scale-solid phase micropore method. In this paper, a purification process for the growth of urea ammonium chloride eutectic by solid phase method is studied. The purpose of this process is to separate and purify the pure U-AC, which is easy to be studied in the future and the separation and purification process of .U-AC is composed of a series of operations. It is mainly divided into two parts: in the first part, the crude products of urea ammonium chloride are obtained by recrystallization; in the second part, the recrystallization products are further separated and purified by density sorting method. Finally, the purification process was tested on industrial scale. First of all, because urea ammonium chloride eutectic is grown in compound fertilizer particles, urea ammonium chloride eutectic is initially separated from compound fertilizer particles by wind separation method, and then dissolved and filtered. Amino acid assisted recrystallization gave urea ammonium chloride crude product. By comparing the recrystallization yield of urea ammonium chloride before and after the addition of inhibitor amino acids, the amino acids which can inhibit the decomposition of urea ammonium chloride were selected, and the concentration of the inhibitor and the recrystallization temperature were selected. Finally, the mechanism of L-cysteine inhibiting the decomposition of urea ammonium chloride was analyzed. Compared with direct recrystallization, the yield of L-cysteine assisted U-AC recrystallization increased from 52.41% to 78.26%. Secondly, because urea ammonium chloride is easy to decompose, the recrystallization product is still a mixture containing urea, ammonium chloride and other impurities. Using benzene and carbon tetrachloride as separation medium, urea and ammonium chloride were removed by density separation method. The volume ratio of benzene to carbon tetrachloride is 1: 2 for the first time, when urea floats on the surface of the medium, ammonium chloride and urea ammonium chloride precipitate in the lower layer. A second separation of substances from the first lower layer to remove ammonium chloride is achieved, when the volume of benzene and carbon tetrachloride is 1: 4.5. In this proportion, ammonium urea chloride floats on the surface of the medium. Ammonium chloride is deposited at the bottom of the medium. The target substance can be obtained by filtration after each separation. Finally, the target compound was identified by XRD, and the content of chlorine and nitrogen was compared with the standard value. The results show that the purity of U-AC is greatly improved. Finally, the purification method was applied to the large-scale purification process, and the properties of urea ammonium chloride were studied. It was found that the urea ammonium chloride solution had fire resistance and could be used as refractories.
【学位授予单位】：山西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ441.41

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