【摘要】：鉻鹽及鉻系列化合物為重要的基礎(chǔ)化工原料。針對(duì)傳統(tǒng)有鈣焙燒法鉻鹽生產(chǎn)工藝過(guò)程存在的資源利用率低和環(huán)境污染嚴(yán)重等問題，中國(guó)科學(xué)院過(guò)程工程研究所研發(fā)了具有我國(guó)自主知識(shí)產(chǎn)權(quán)的液相氧化法鉻鹽清潔生產(chǎn)工藝。中間產(chǎn)品鉻酸鈉的結(jié)晶相分離為該工藝的重要組成部分，其純度和形貌將直接影響下游產(chǎn)品的質(zhì)量和生產(chǎn)成本。本文選擇了Na2CrO4-NaOH-NaAlO2-H2O體系，對(duì)鉻酸鈉結(jié)晶分離過(guò)程的相平衡、介穩(wěn)區(qū)、動(dòng)力學(xué)及工藝過(guò)程優(yōu)化等問題進(jìn)行了系統(tǒng)的應(yīng)用基礎(chǔ)研究。主要取得了以下創(chuàng)新性進(jìn)展： 1)測(cè)定了Na2CrO4-NaOH-H2O三元體系在90℃、120℃和130℃時(shí)以及Na2CrO4-NaOH-NaAlO2-H2O四元體系在90℃、120℃和130℃時(shí)的相平衡數(shù)據(jù)，繪制了Na2CrO4-NaOH-H2O三元體系在90℃以及Na2CrO4-NaOH-NaAlO2-H2O四元體系在120℃和130℃的相圖，為鉻酸鈉結(jié)晶分離提供了基礎(chǔ)數(shù)據(jù)； 2)研究了鉻酸鈉在Na2CrO4-NaOH-H2O體系中的結(jié)晶介穩(wěn)區(qū)以及雜質(zhì)(NaAlO2)含量對(duì)介穩(wěn)區(qū)寬度的影響，分別討論了不同堿濃度下真空蒸發(fā)結(jié)晶過(guò)程中的壓力與沸點(diǎn)的關(guān)系，同一溶液濃度體系下，真空度越高，，溶液的沸點(diǎn)越低，隨著體系濃度的升高，沸點(diǎn)上升，所需真空度也升高； 3)采用間歇?jiǎng)討B(tài)法研究了鉻酸鈉蒸發(fā)結(jié)晶過(guò)程動(dòng)力學(xué)，用最小二乘法進(jìn)行回歸分析，得到了相應(yīng)的結(jié)晶動(dòng)力學(xué)方程，闡述了懸浮密度、攪拌速率、過(guò)飽和度和雜質(zhì)對(duì)蒸發(fā)結(jié)晶過(guò)程的影響規(guī)律，隨著懸浮密度、攪拌速率、過(guò)飽和度和雜質(zhì)含量的增大均更有利于晶體的成核； 4)開展了鉻酸鈉蒸發(fā)結(jié)晶工藝優(yōu)化研究，系統(tǒng)分析討論了蒸發(fā)結(jié)晶過(guò)程中攪拌強(qiáng)度、蒸發(fā)速度、結(jié)晶溫度、雜質(zhì)含量、晶種添加對(duì)產(chǎn)品平均粒度及粒度分布、純度和晶習(xí)的影響規(guī)律，確定出鉻酸鈉蒸發(fā)結(jié)晶的最優(yōu)工藝條件為：攪拌速度為300r/min；蒸發(fā)速率約為150~200mL；結(jié)晶溫度為90℃；雜質(zhì)含量小于3g/L；添加晶種，在以上操作條件下可制備出粒度分布均勻，純度可達(dá)97.5%以上的鉻酸鈉產(chǎn)品。
[Abstract]:Chromium salts and chromium series compounds are important basic chemical raw materials. In view of the problems of low resource utilization and serious environmental pollution in the traditional chromium salt production process with calcium roasting, the Institute of process Engineering of the Chinese Academy of Sciences has developed a clean production process of chromium salt by liquid oxidation with independent intellectual property rights in China. The crystallization phase separation of intermediate product sodium chromate is an important part of this process. Its purity and morphology will directly affect the quality and production cost of downstream products. In this paper, the phase equilibrium, metastable region, kinetics and process optimization of crystallization separation process of sodium chromate have been systematically studied in Na2CrO4-NaOH-NaAlO2-H2O system. The main achievements are as follows: 1) the phase equilibrium data of Na2CrO4-NaOH-H2O ternary system at 90 鈩

本文編號(hào)：2374205