本文選題：磷酸二氫鉀 + 介穩(wěn)區(qū)　； 參考：《天津工業(yè)大學(xué)》2017年碩士論文

【摘要】：采用重結(jié)晶的方法研究了磷酸二氫鉀在水溶液中的結(jié)晶行為,探討了攪拌速率、降溫速率、pH值及金屬離子摻雜等因素對(duì)其介穩(wěn)區(qū)寬度、結(jié)晶速率、結(jié)晶形態(tài)、晶體粒徑大小及粒度分布等的影響規(guī)律,對(duì)磷酸二氫鉀在水溶液中的結(jié)晶工藝進(jìn)行了研究;在最佳結(jié)晶工藝條件下,晶體粒度分布均勻、粒徑較大,將優(yōu)化的結(jié)晶工藝應(yīng)用到聚醚多元醇后處理精制過程中能明顯縮短聚醚后處理精制周期,提高聚醚生產(chǎn)效率。研究表明:隨著攪拌速率的增大磷酸二氫鉀溶液介穩(wěn)區(qū)寬度變窄,誘導(dǎo)期縮短,降溫速率和溶液的pH 一定,當(dāng)攪拌速率為300r/min時(shí),結(jié)晶速率最小為0.43g/min;隨著降溫速率的增加,介穩(wěn)區(qū)寬度逐漸增加,誘導(dǎo)期和晶體的平均粒徑均減小,降溫速率為0.3℃/min時(shí),晶體的平均粒徑最大為530.21μm;在pH=3時(shí),介穩(wěn)區(qū)寬度和誘導(dǎo)期達(dá)到最小,結(jié)晶速率達(dá)到最大為1.3g/min;控制攪拌速率為200r/min,降溫速率為0.5℃/min,溶液的pH值為3.0時(shí),從水溶液中結(jié)晶得到的磷酸二氫鉀晶體顆粒均勻且粒徑較大為417.65μm,并且此條件下結(jié)晶可有效防止晶簇。本文研究了磷酸二氫鉀結(jié)晶技術(shù)在聚醚后處理實(shí)際生產(chǎn)過程中的應(yīng)用,優(yōu)化了針對(duì)不同分子量聚醚乳液中通過磷酸中和,結(jié)晶析出磷酸二氫鉀,過濾等工序去除催化劑金屬離子的聚醚后處理精制工藝�？刂芅a+/K+摩爾摻雜比為1:1,攪拌速率90～110r/min,pH值3～4范圍內(nèi),能夠得到粒度分布均勻、顆粒較大的磷酸二氫鹽晶體;精制處理后聚醚中鉀、鈉金屬離子平均含量分別為2.6ppm和2.2ppm,且鉀鈉離子含量的總和小于現(xiàn)行業(yè)5ppm的要求;磷酸二氫鉀及磷酸二氫鈉結(jié)晶析出顆粒較大,且形成了良好的架橋效應(yīng),體系粘度低,過濾速度快,能顯著縮短聚醚后處理過濾循環(huán)及過濾時(shí)間,提高聚醚精制后處理過程的生產(chǎn)效率,聚醚后處理結(jié)晶工藝的優(yōu)化對(duì)實(shí)際生產(chǎn)過程有著積極的指導(dǎo)意義。
[Abstract]:The crystallization behavior of potassium dihydrogen phosphate in aqueous solution was studied by recrystallization method. The effects of stirring rate, cooling rate, pH value and metal ion doping on the metastable zone width, crystallization rate and crystal morphology of potassium dihydrogen phosphate were investigated. The crystallization process of potassium dihydrogen phosphate in aqueous solution was studied under the optimum crystallization conditions, the crystal size distribution was uniform and the particle size was large. The application of the optimized crystallization process to the process of polyether polyol aftertreatment can obviously shorten the refining period of polyether and improve the production efficiency of polyether. The results show that with the increase of stirring rate, the width of the metastable zone of potassium dihydrogen phosphate solution becomes narrower, the induction period is shorter, the cooling rate and pH of the solution are constant, the minimum crystallization rate is 0.43 g / min when the stirring rate is 300r/min, and the minimum crystallization rate is 0.43 g / min with the increase of the cooling rate. The width of the metastable zone increases gradually, and the average particle size of the crystal decreases during the induction period. When the cooling rate is 0.3 鈩，

本文編號(hào)：1877071