本文選題：雙氰胺 + 離子交換��； 參考：《寧夏大學(xué)》2017年碩士論文

【摘要】：雙氰胺是一種重要的精細(xì)化工材料,普遍應(yīng)用于制藥、電子、紡織、印刷等行業(yè)。由于生產(chǎn)過程中脫鈣的不徹底導(dǎo)致后續(xù)雙氰胺結(jié)晶母液中含有Ca(OH)2、CaCO3等含鈣化合物,如以Ca2+計(jì),含量約1500mg·kg-1。雜質(zhì)的存在嚴(yán)重影響了雙氰胺的純度及品質(zhì)。本文通過在原有生產(chǎn)工藝基礎(chǔ)上,在結(jié)晶工段前引入離子交換法進(jìn)行精脫鈣,通過系統(tǒng)研究離子交換-結(jié)晶耦合工藝獲得較優(yōu)工藝條件,使雙氰胺產(chǎn)品中Ca2+含量達(dá)到醫(yī)藥級雙氰胺產(chǎn)品的要求。首先,通過比較D001、001×4、001×7、001×8四種型號的樹脂對雙氰胺結(jié)晶母液中鈣離子的吸附量,發(fā)現(xiàn)在相同的實(shí)驗(yàn)條件下,001×7型樹脂對鈣離子的吸附量最大,單位體積吸附量達(dá)到68.15mg,并考慮經(jīng)濟(jì)性,本文選用001×7型樹脂,并對雙氰胺結(jié)晶母液中的Ca2+進(jìn)行靜態(tài)和動態(tài)交換實(shí)驗(yàn)。靜態(tài)實(shí)驗(yàn)結(jié)果表明:在反應(yīng)時間80min、溫度45-50℃、樹脂用量為40mL(空隙率0.42,下同)、攪拌速率250r·min-1的最佳工藝條件下處理200mL雙氰胺結(jié)晶母液,Ca2+脫除率達(dá)到98.12%,交換后雙氰胺結(jié)晶母液中鈣離子含量為27.17mg·kg-1。動態(tài)實(shí)驗(yàn)裝置采用高600mm、內(nèi)徑為40mm的玻璃柱。采用100mL樹脂處理500mL雙氰胺母液,母液流速為5mL·min-1,樹脂床層高徑比為5.3:1,交換柱內(nèi)樹脂床層交換溫度為45-50℃,在此條件下脫鈣率達(dá)到了97.32%,母液中鈣離子含量低至38.71mg·kg-1,同時獲得該過程的貫穿函數(shù),并對動態(tài)過程的行為進(jìn)行模擬進(jìn)而揭示了動態(tài)離子交換的特征。在已有的分形多孔介質(zhì)理論基礎(chǔ)上,結(jié)合動態(tài)離子交換過程,通過實(shí)驗(yàn)數(shù)據(jù)擬合得出了離子交換過程樹脂分形表面譜維數(shù)的計(jì)算方程為線性關(guān)系(相關(guān)性系數(shù)為0.992),利用方程的斜率求得該交換過程的分形表面譜維數(shù)為ds=2.21,并且得到了數(shù)學(xué)模型。通過分析理想表面與分形表面動力學(xué)方程中1/Ct與t關(guān)系,得出理想表面為線性關(guān)系,分形表面為冪函數(shù)關(guān)系。最后,通過前期單因素實(shí)驗(yàn)結(jié)果,采用響應(yīng)曲面法優(yōu)化結(jié)晶工藝,得到最佳工藝條件為:降溫速率0.3℃·min-1,攪拌速率300r·min-1,晶種粒度60目,養(yǎng)晶時間30min,在該最佳工藝條件下Ca2+脫除率達(dá)到97.86%,雙氰胺結(jié)晶產(chǎn)品中的鈣含量為32.29mg·kg-1。達(dá)到了醫(yī)藥級雙氰胺產(chǎn)品對Ca2+含量的要求。本文研究成果為工業(yè)生產(chǎn)高品質(zhì)雙氰胺提供基礎(chǔ)。
[Abstract]:Dicyandiamide is an important fine chemical material, widely used in pharmaceutical, electronics, textile, printing and other industries. Because of the incomplete decalcification in the process of production, the subsequent dicyandiamide crystallization mother liquor contains calcium compounds such as CaOHHf2CaCO3, such as Ca2, the content of which is about 1500mg kg ~ (-1). The purity and quality of dicyandiamide were seriously affected by the presence of impurities. In this paper, on the basis of the original production process, the ion exchange method was introduced before the crystallization section for fine decalcification, and the better process conditions were obtained by systematically studying the ion exchange-crystallization coupling process. The content of Ca2 in dicyandiamide product is up to the requirement of pharmaceutical grade dicyandiamide product. First of all, by comparing the adsorption amount of calcium ions in dicyandiamide crystal mother liquor by D001001 脳 4001 脳 7001 脳 8 resin, it is found that the adsorption amount of calcium ion on D001001 脳 4001 脳 7001 脳 8 resin is the largest under the same experimental conditions, and the adsorption capacity per unit volume is 68.15mg. The static and dynamic exchange experiments of Ca2 in dicyandiamide crystal mother liquor were carried out by using 001 脳 7 resin. The static experiment results show that the reaction time is 80 min and the temperature is 45-50 鈩，

本文編號：1875533