本文選題：綠液 + 鋁鹽改性膨潤土��； 參考：《陜西科技大學(xué)》2015年碩士論文

【摘要】：本論文針對非木材纖維原料制漿廠廣泛存在的“硅干擾”問題,將我國資源豐富的,易改性,膨脹性好,吸附性強的膨潤土引入綠液除硅體系,制備了一種新型高效可循環(huán)的除硅劑—鋁鹽改性膨潤土,改善了傳統(tǒng)綠液除硅劑的除硅效率低,對綠液p H影響大,難沉降等缺點,并系統(tǒng)地介紹了其制備工藝,除硅工藝,脫附再生工藝。本論文以國家提出的“十二五節(jié)能減排規(guī)劃”為目標(biāo),綜合利用我國豐富的礦物質(zhì)資源,未來可實現(xiàn)企業(yè)的節(jié)能減排,實現(xiàn)循環(huán)經(jīng)濟,達到環(huán)境保護的目的,具有廣闊的市場應(yīng)用前景。(1)鋁鹽改性膨潤土制備工藝與機理以鈉基膨潤土為原料,通過添加鋁鹽為改性劑制備出了一種新型高效的綠液除硅劑,其硅吸附效率最高可達90%左右。以竹漿綠液的硅吸附率和p H變化為標(biāo)準(zhǔn)研究了改性膨潤土的制備工藝,其最佳工藝為:鈉基膨潤土與鋁鹽的質(zhì)量比為1:4,添加順序為:先將鈉基膨潤土與水混合,再加入鋁鹽,加水量為66m L/1g鈉基膨潤土,攪拌時間為2h,攪拌速率為1200r/min,反應(yīng)溫度為室溫,靜置分離12h,105℃干燥,研磨,過200目篩。經(jīng)過掃描電鏡,X射線衍射,熱分析,紅外光譜分析以及粒徑分布表征了鋁鹽改性膨潤土的特征,推斷其制備機理為:鈉基膨潤土的表面與層間分布著鈉原子和一定的羥基,先向鈉基膨潤土中加入水?dāng)嚢?有助于打開鈉基膨潤土的層間,增大膨潤土的層間距,有利于改性劑的引入,當(dāng)鈉基膨潤土在水中攪拌均勻后,加入鋁鹽改性劑,由于鋁原子親羥基性能比鈉原子強,鋁鹽開始進入到膨潤土層間置換鈉原子,鈉原子從膨潤土體系中游離出,并且,鋁鹽開始水解成為聚合羥基鋁鹽,當(dāng)攪拌2h后,鋁原子已經(jīng)基本上將鈉原子置換完全并且膨潤土表面連接了大量的Al-OH,則鋁鹽改性膨潤土制備完畢。(2)鋁鹽改性膨潤土除硅工藝與機理鋁鹽改性膨潤土除硅工藝最佳操作條件為:改性膨潤土用量16g/L,攪拌時間為10 min,溫度為90℃,平衡時間為5 min。通過改性膨潤土對竹漿綠液(硅酸鹽含量為4g/L)的吸附動力學(xué),等溫模型擬合和反應(yīng)熱力學(xué)的研究,可得,其吸附過程符合二級動力學(xué)模型,是物理吸附和化學(xué)吸附的共同效果。最大吸附量為252.525mg/g,與實驗中得出的最大吸附量238.441mg/g相符。另外,改性膨潤土的吸附過程更符合Freundlich模型,并且1/n1,可知該吸附反應(yīng)容易進行,并且吸附能力強。通過簡單的熱力學(xué)研究發(fā)現(xiàn),該吸附過程屬于自發(fā)進行,不需要附加能來實現(xiàn)。鋁鹽改性膨潤土吸附硅酸鹽的物理吸附主要依靠膨潤土層間的縫隙來實現(xiàn),但吸附性能差;而化學(xué)吸附占主導(dǎo)因素,其吸附機理為:硅酸鹽在竹漿綠液中(強堿性溶液)主要以Si-OH鍵的形式存在,而鋁鹽改性膨潤土表面存在大量的Al-OH,當(dāng)鋁鹽改性膨潤土加入竹漿綠液后,Al-OH鍵與Si-OH鍵發(fā)生化學(xué)吸附反應(yīng),硅元素被吸附在膨潤土表面。反應(yīng)結(jié)束后,經(jīng)過濾,硅元素被鋁鹽改性膨潤土帶走,成功實現(xiàn)除硅目的。(3)鋁鹽改性膨潤土絮凝除硅工藝及機理的研究鋁鹽改性膨潤土最佳絮凝除硅工藝:絮凝劑為鋁鹽改性膨潤土-CPAM-Ca O,可以高效除硅,最高硅去除率可達99.9%,還可以降低除硅劑對綠液p H值的影響和加快硅酸鹽的沉降。所以,絮凝除硅工藝是一種新型高效環(huán)保的除硅工藝。最佳條件為:鋁鹽改性膨潤土用量16 g/L,CPAM用量15 m L/L,Ca O用量15 g/L,攪拌時間10min,澄清時間5 min。在絮凝除硅工段中,鋁鹽改性膨潤土先與綠液中的硅酸鹽充分接觸,吸附。然后加入CPAM絮凝劑和Ca O助絮凝劑,CPAM趨于“環(huán)和尾”式吸附狀態(tài),充當(dāng)交聯(lián)架橋作用,使原來分散的吸附絮凝體,聯(lián)結(jié)成締合狀聚集體,少量絮凝劑是讓其到達等當(dāng)點,從而形成片塊狀聚集體,快速下沉,使聚集體盡快脫離上層清液,加速了沉降速率,減少了澄清時間。(4)鋁鹽改性膨潤土脫附再生工藝的研究鋁鹽改性膨潤土脫附再生工藝可描述為將回收的使用后的鋁鹽改性膨潤土加入到2mol/L氫氧化鈉的堿性溶液中,微波中火加熱4min(或者直接加熱4h),連接在鋁鹽改性膨潤土上的硅酸鹽從鋁鹽改性膨潤土上游離下來,過濾。脫附后的鋁鹽改性膨潤土留在濾網(wǎng)上,硅酸鹽進入綠液中,冷卻,硅酸鹽固體析出。過濾,干燥,硅酸鹽被完整脫附出來。將脫附后的鋁鹽改性膨潤土加入到水中,攪拌,加入鋁鹽改性劑,攪拌2h,靜置分離,倒去上清液,干燥下濁液,研磨,過篩,就得到了再生鋁鹽改性膨潤土。考慮成本及設(shè)備耗能等影響,建議循環(huán)2-3次使用。另外,脫附動力學(xué)研究表明鋁鹽改性膨潤土脫附硅酸鹽的過程在高強度微波下與二階動力學(xué)模型相符,磁場力既促進了物理脫附也促進了化學(xué)脫附。其飽和脫附量為129.870 mg/g,與實驗測試過程中測定出的120.948 mg/g相符。最后,通過掃描電鏡,紅外光譜和能譜分析對脫附物的成分進行鑒定,脫附物的主要成分為鋁硅酸鹽。
[Abstract]:This paper, aiming at the widespread "Silicon Interference" problem in the non wood fiber raw material pulping plant, introduces a new highly efficient and recyclable silicon removing agent, aluminum salt modified bentonite, which has rich resources, modifier, expansibility and strong adsorbability of bentonite, and improves the efficiency of removing silicon from traditional green liquid desilication agent. Low, large influence on green liquid p H, difficult to settle and other shortcomings, and systematically introduced its preparation technology, the removal of silicon technology, desorption and regeneration process. In this paper, the national "12th Five-Year energy saving and emission reduction plan" as the goal, the comprehensive utilization of China's rich mineral resources, the future can realize the enterprise energy conservation and emission reduction, the realization of the circular economy, to achieve environmental protection. The purpose of protection has broad market application prospects. (1) the preparation technology and mechanism of aluminum salt modified bentonite is made of sodium bentonite as raw material. A new type of high efficient green liquid silicon removal agent is prepared by adding aluminum salt as modifier, and its silicon adsorption efficiency is up to about 90%. The silicon adsorption rate and P H change of bamboo pulp green solution are studied as the standard. The optimum process for the preparation of modified bentonite is that the mass ratio of sodium base bentonite and aluminum salt is 1:4, and the addition order is: first mixing sodium bentonite with water, adding aluminum salt and adding 66m L/1g sodium bentonite, stirring time is 2h, stirring rate is 1200r/min, reaction temperature is room temperature, static separation 12h, 105 DEG C drying, lapping, over 200 mesh sieve. The characteristics of aluminum salt modified bentonite were characterized by scanning electron microscopy, X ray diffraction, thermal analysis, infrared spectrum analysis and particle size distribution. It was concluded that the mechanism of the preparation of sodium based bentonite was that the surface and layer of sodium base bentonite were distributed with sodium atom and certain hydroxyl group, and the sodium base bentonite was added to the sodium bentonite to stir the sodium bentonite. Between layers, increasing the spacing of bentonite is beneficial to the introduction of the modifier. When the sodium bentonite is stirred in the water, the aluminum salt modifier is added. As the aluminum atom is stronger than the sodium atom, the aluminum salt begins to go into the bentonite to replace the sodium atom, and the sodium atom is dissociated from the bentonite system, and the aluminum salt begins to hydrolyze into the sodium bentonite. After mixing 2h, the aluminum atom has basically replaced the sodium atom completely and the bentonite surface is connected with a large amount of Al-OH, then the aluminum salt modified bentonite is prepared. (2) the best operation condition of the aluminum salt modified bentonite removal process and the mechanism of the aluminum salt modified bentonite removal process is that the modified bentonite is used for 16g/L and stirred. The time is 10 min, the temperature is 90, and the equilibrium time is 5 min.. The adsorption kinetics of the bamboo pulp green solution (silicate content is 4g/L) by the modified bentonite, the isothermal model fitting and the reaction thermodynamics study. The adsorption process accords with the two stage kinetic model, which is the common effect of physical absorption and chemical adsorption. The maximum adsorption amount is 252.525m G/g is in accordance with the maximum adsorption amount of 238.441mg/g obtained in the experiment. In addition, the adsorption process of the modified bentonite is more in line with the Freundlich model, and 1/n1. It is known that the adsorption reaction is easy to carry out and has strong adsorption capacity. Through a simple thermodynamic study, it is found that the adsorption process is spontaneous and does not need additional energy to achieve. The physical adsorption of Bentonite on silicate mainly depends on the gap between bentonite layers, but the adsorption property is poor, and chemical adsorption is the dominant factor. The mechanism of adsorption is that silicate is mainly in the form of Si-OH bond in bamboo pulp green solution (strong alkali solution), and there is a large amount of Al-OH on the surface of aluminum salt modified bentonite, when aluminum salt is modified. After the bentonite is added to the bamboo pulp green solution, the Al-OH bond and the Si-OH bond have a chemical adsorption reaction, the silicon element is adsorbed on the bentonite surface. After the reaction, the silicon elements are removed by the aluminum salt modified bentonite and the silicon removal is successfully carried out. (3) the study on the process and mechanism of the flocculation and removal of silicon by aluminum salt modified bentonite is the best flocculation of the aluminum salt modified bentonite. Silicon process: the flocculant is al salt modified bentonite -CPAM-Ca O, which can remove silicon efficiently and the highest silicon removal rate can reach 99.9%. It can also reduce the effect of silicon removing agent on the P H value of green solution and accelerate the settlement of silicate. Therefore, flocculation and desilication process is a new efficient and environmentally friendly technology for removing silicon. The best condition is that the amount of aluminum salt modified bentonite is 16 g/L, CP The dosage of AM is 15 m L/L, Ca O is 15 g/L, stirring time 10min, and the time of clarification is 5 min. in the flocculating and removing silicon section. The aluminum salt modified bentonite is in full contact with the silicate in the green liquid first and adsorbed. Then CPAM flocculant and Ca O flocculant are added, and CPAM tends to "ring and tail" adsorption state and acts as crosslinking bridge to make the original dispersed adsorption. Floc forming a associative aggregate, a small amount of flocculant is to make it arrive at the same point, thus forming a lump aggregate, rapidly sinking, making the aggregate out of the upper liquid as soon as possible, accelerating the settling rate and reducing the time of clarification. (4) a study on the process of aluminum salt modified bentonite desorbing regenerative process can be traced. The recycled aluminum salt modified bentonite is added to the alkaline solution of 2mol/L sodium hydroxide. The microwave heat is heated for 4min (or directly heated to 4h). The silicate connected to the aluminum salt modified bentonite is dissociated from the aluminum salt modified bentonite and filtered. The aluminum salt modified bentonite is left on the filter net and the silicate is entered. In green liquid, cooling, silicate solid precipitation, filtration, drying, and silicate are completely removed. The aluminum salt modified bentonite is added to water, mixing, adding aluminum salt modifier, stirring 2h, statically separating, pouring the supernatant, drying turbid liquid, grinding, sifting, and obtaining the regenerated aluminum salt bentonite. Cost and equipment consumption are considered. In addition, the kinetic study shows that the process of desorption of silicate by aluminum salt modified bentonite is consistent with the two order kinetic model under high intensity microwave. The magnetic force not only promotes physical desorption but also promotes chemical desorption. The saturation desorption amount is 129.870 mg/g, and 12 measured in the test process. 0.948 mg/g coincide. Finally, the components of the desorption were identified by scanning electron microscopy, infrared spectroscopy and energy spectrum analysis. The main component of the desorption was aluminosilicate.

【學(xué)位授予單位】：陜西科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X793

【參考文獻】

相關(guān)期刊論文 前10條

1 童國林,陸琦,汪陸捚,周彩虹;硅鉬藍光度法測定稻草原料及燒堿法制漿黑液的硅含量[J];中華紙業(yè);2005年08期

2 徐永建;潘剛;黨佩;;氧化鈣、氧化鎂協(xié)同氧化鋁留硅蒸煮工藝研究[J];中華紙業(yè);2010年06期

3 張珂,汪蘋;提高麥草漿黑液堿回收率的幾個關(guān)鍵問題[J];中華紙業(yè);1999年03期

4 郭X梅,馬毅杰,韓和平;膨潤土對Pb~(2+)的吸附性能及影響吸附的主要因素[J];環(huán)境科學(xué)學(xué)報;2000年05期

5 賀連娟;;麥草漿黑液石灰法除硅試驗研究[J];科技信息(科學(xué)教研);2008年02期

6 何宏平,謝先德,郭九皋;離子交換蒙脫石的熱穩(wěn)定性研究[J];礦物巖石;2000年01期

7 于桂香，張德金;膨潤土及其開發(fā)利用[J];遼寧化工;1994年02期

8 王重,李運康,陳德芳;有機膨潤土合成工藝及性能的研究[J];西安交通大學(xué)學(xué)報;2000年08期

9 吳平霄;無機插層蒙脫石功能材料的微結(jié)構(gòu)變化研究[J];現(xiàn)代化工;2003年07期

10 林濤;李雪;殷學(xué)風(fēng);任建曉;付s，

本文編號：1883168