本文關(guān)鍵詞： 稻殼灰 白炭黑 KH570 聚乙二醇6000 碳酸鈉 表面改性　出處：《安徽工程大學》2015年碩士論文　論文類型：學位論文

【摘要】：我國年產(chǎn)稻殼(RH)約0.4億噸,完全燃燒時具有90%左右的含硅量。目前多數(shù)作為廢棄物丟棄,利用率低,并且產(chǎn)生的稻殼灰(RHA)也不能及時處理。本著合理利用資源,提高經(jīng)濟附加值和保護環(huán)境的目的,本文以發(fā)電RHA為原料,采用Na2CO3溶液沉淀法將RHA中的Si02溶出制備白炭黑,對RH資源進一步綜合回收利用。本文首先對RHA中的Si02溶出工藝參數(shù)進行優(yōu)化,考察反應溫度、料液比、Na2CO3溶液濃度及反應時間等的參數(shù)對Si02溶出率的影響,并探索洗滌液的調(diào)節(jié)濃度對濾液循環(huán)使用的影響。然后重點探索了對白炭黑成品的KH偶聯(lián)改性和在濾餅階段的PEG6000改性,解決沉淀法白炭黑的團聚問題,用于提高產(chǎn)品的分散性、疏水性活化指數(shù)和DBP吸收值。主要研究內(nèi)容及結(jié)論如下：從稻殼灰中采用沉淀法提取白炭黑,通過單因素實驗和響應曲面法,對提取工藝進行優(yōu)化,結(jié)果顯示：當反應溫度100℃、料液比15 g：300 mL、Na2CO3溶液濃度20wt.%、反應時間3h時,SiO2的溶出率達到92.39%。考察碳酸鈉溶液循環(huán)使用情況,發(fā)現(xiàn)當將濾餅的洗滌液配制成10wt.%的Na2CO3溶液用于補償反應過程中Na2CO3溶液的損失時,其他條件不變,RHA中SiO2的溶出率仍能達到90%以上,說明反應后的濾液可以循環(huán)使用,而且洗滌液和冷卻用水也可回收利用,既節(jié)約成本也可減少污水排放。FT-IR光譜表明,所得產(chǎn)品為白炭黑,且表面存在大量羥基和吸附水,顆粒容易團聚。XRD結(jié)果表明,所得白炭黑是典型的無定形結(jié)構(gòu)。SEM圖片顯示,產(chǎn)品粒子之間具有較嚴重的團聚現(xiàn)象,且粒子分布不均,單個粒子不易區(qū)分。KH570改性成品白炭黑的結(jié)果表明：當將約5g的產(chǎn)品分散在90 mL溶液,控制反應體系pH4-5,加入5 mL改性劑,在90℃下反應70 min,所得改性樣品的疏水性活化指數(shù)達100%,產(chǎn)品的DBP吸收值由原來的1.97mL/g降低到1.15mL/g左右,說明產(chǎn)品聚集狀態(tài)減弱,分散顆粒的均勻性有所提高。產(chǎn)品的粒度分析表明,原產(chǎn)品經(jīng)KH570改性后,粒徑總體變化不大,但團聚體更容易得到分散；FT-IR檢測表明,KH570水解后的產(chǎn)物順利與粒子表面-OH鍵合；改性前后的BJH孔徑分析表明,成品白炭黑經(jīng)KH570改性后,會使產(chǎn)品所具有的大孔和較大的比表面積遭到破壞,生長的簇團會被解離,導致改性的產(chǎn)品DBP吸收值大大降低,但產(chǎn)品的有機溶劑分散性和疏水性會得到提高。SEM顯示,改性前的粒子團聚現(xiàn)象減弱,粒子之間更緊湊,孔隙分布更為均勻。在白炭黑濾餅階段采用PEG 6000改性,所得工藝參數(shù)為：將濾餅用80mL水分散,加入用量15wt.%的PEG 6000、在70℃下改性2h,所得產(chǎn)品的DBP吸收值約3.00 mL/g。FT-IR分析表明,濾餅階段的表面改性是可行的,PEG 6000能有效地纏繞接枝在產(chǎn)品表面。粒度分析表明PEG 6000吸附在白炭黑粒子表面,在促進白炭黑粒子凝聚的同時,又能阻止粒子繼續(xù)團聚長大,使粒度分布更均勻,并且能有效地增加產(chǎn)品的孔隙率,提高產(chǎn)物比表面積及分散性。SEM顯示產(chǎn)品團聚體得到釋放,粒子分布更為均勻,總體分散性得到提高。同時,濾餅階段改性處理,更容易把濾餅中包裹的雜質(zhì)離子除去,也使得產(chǎn)品更容易干燥而不結(jié)塊,產(chǎn)品更為疏松且容易粉碎,克服了白炭黑在干燥過程容易結(jié)晶塊的問題。
[Abstract]:China's annual output of about 0.4 tons of rice husk (RH), with about 90% of the total amount of silicon containing combustion. Most discarded as waste, low utilization rate, and the rice husk ash (RHA) can not be timely treatment. The spirit of rational use of resources, protect the environment and improve the economic value added to the power of RHA as the raw material, the preparation of silica dissolution in RHA Si02 precipitation method using Na2CO3 solution of RH resources to further comprehensive utilization. Based on the RHA Si02 in the dissolution process is optimized. The effects of reaction temperature, liquid ratio, parameters of Na2CO3 solution concentration and reaction time on the dissolution rate of Si02 the effect and to explore the effect of regulating the concentration of washing liquid for recycle. And then focus on the KH coupling silica modified and refined in the cake stage of PEG6000 modification, solution precipitation method white carbon black aggregation problem for increasing production Dispersion of goods, hydrophobic activation index and DBP absorption value. The main research contents and conclusions are as follows: from rice husk ash extracted by silica precipitation method, through the single factor experiment and response surface method, the extraction process was optimized, the results show that when the reaction temperature is 100 DEG C, the ratio of material to liquid 15 g:300 mL, Na2CO3 the concentration of 20wt.%, reaction time 3h, SiO2 dissolution rate reached 92.39%. the effects of sodium carbonate solution recycling, will be found when the washing liquid cake made into Na2CO3 solution for 10wt.% Na2CO3 solution in the reaction process of loss, he keeps its condition, RHA SiO2 dissolution rate can still reach more than 90%, indicating that the reaction after the filtrate can be recycled, and the washing liquid and cooling water Recyclable utilization, thereby saving cost, reduce sewage emissions can also indicate the.FT-IR spectrum, the product is white carbon black, and there are a large number of surface hydroxyl The base and adsorbed water, particles are easy to agglomerate.XRD results show that the silica is amorphous structure of typical.SEM image display, which is a serious phenomenon of agglomeration between the particles and the particles are, the uneven distribution of individual particles are not easy to distinguish.KH570 modified silica products. The results show that when the products dispersed about 5g in 90 mL solution, reaction control system pH4-5, adding 5 mL modifier, 70 min reaction at 90 DEG C, the activation index of hydrophobic modified samples is up to 100%. The product of DBP absorption value was reduced from 1.97mL/g to 1.15mL/g, the product aggregation weakens, uniformity of dispersed particles increased product size. Analysis shows that the original product modified by KH570, the particle size changed little overall, but the aggregate more easily spread; FT-IR showed that the product of hydrolysis of KH570 particles and smooth surface of -OH bonding; BJ before and after modification The diameter of H analysis showed that the product of silica modified by KH570, the product has a large hole and a large surface area is destroyed, the growth of clusters will be led to dissociation, modified products DBP absorption value is greatly reduced, but the organic solvent dispersion and hydrophobic products will be improved.SEM showed that the modified particle weakened agglomeration between the particles is more compact, more uniform pore distribution. Using PEG 6000 modified silica phase in filter cake, the process parameters were as follows: the filter cake with 80mL aqueous dispersion, adding amount of 15wt.% PEG 6000, modified 2H at 70 DEG C, the the DBP absorption value of approximately 3 mL/g.FT-IR analysis showed that the surface of the cake stage modification is feasible, PEG 6000 winding grafting on the surface of the product effectively. Particle size analysis showed that PEG 6000 adsorbed on the silica surface, in the promotion of silica particle condensation at the same time, but also can prevent The particle to agglomerate, the particle size distribution is more uniform, and can effectively increase the porosity of the products, improve the product specific surface area and dispersion of.SEM display products aggregates to be released, the particle distribution is more uniform, the overall dispersion is improved. At the same time, cake stage modification, the impurity ions more easily wrapped cake the removal, also makes the product easier to dry without caking, products are more loose and easily broken, overcome the problem of the block easy crystallization of silica in the drying process.

【學位授予單位】：安徽工程大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ127.2

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