稻殼灰中二氧化硅的利用
發(fā)布時間：2018-07-29 11:55
【摘要】：隨著化石資源日趨匱乏和社會對能源需求不斷增長，全球能量消耗從2001年的4.04×1017kW增加到2025年的6.40×1017kW，增長58%。因此，尋找一種可再生和可替代的能源資源已經(jīng)成為必然的趨勢。我國是農(nóng)業(yè)大國，生物質(zhì)產(chǎn)量大、價格低、可再生，僅稻殼年產(chǎn)量就達8000萬噸，在國家優(yōu)惠政策的支持下，利用稻殼發(fā)電技術(shù)已經(jīng)在全國推廣，為我國秸稈資源利用和緩解電力緊張做出了貢獻。但是由于受到收集、運輸、價格的影響，很難維持企業(yè)經(jīng)營，同時大量稻殼灰沒有利用不僅造成資源浪費，，而且容易引起灰塵飛揚污染環(huán)境，因此，稻殼灰的綜合利用具有重要的研究價值。 本論文以熱解副產(chǎn)的稻殼灰為原料，對其中的硅源進行了提取和利用。 首先采用堿溶的方法分離稻殼灰中二氧化硅和炭，分離硅酸鈉溶液和炭，炭作為制備活性炭原料。詳細研究了固液比、溶出時間、溶出溫度以及堿濃度對二氧化硅溶出率的影響，確定了最佳反應(yīng)條件；在固液比為1:8、溶出溫度為100oC、溶出時間為2.5h、NaOH的濃度為10wt%的條件下，二氧化硅的溶出率可以達到93.26wt%，模數(shù)為0.82。 然后以硅酸鈉溶液為原料，采用液相結(jié)晶法制備含有結(jié)晶水的偏硅酸鈉晶體。實驗研究了固含量、溶液模數(shù)、結(jié)晶溫度及晶種對偏硅酸鈉晶體生成的影響，探討了反應(yīng)條件對偏硅酸鈉所帶結(jié)晶水個數(shù)的影響。實驗結(jié)果證明，以酸預(yù)處理的稻殼灰為原料，堿溶制備的硅酸鈉溶液經(jīng)濃縮，在不同條件下冷卻結(jié)晶，可以成功地制取不同的偏硅酸鈉產(chǎn)品。在溫度為35oC，模數(shù)在0.5-0.8范圍內(nèi)均能制備五水偏硅酸鈉；固含量為45%-55%硅酸鈉溶液室溫冷卻結(jié)晶，在晶種存在下，當(dāng)模數(shù)為0.7時，產(chǎn)品為五水偏硅酸鈉一等品，當(dāng)模數(shù)為0.8時，產(chǎn)品為六水偏硅酸鈉；在120oC下脫水制備出無水偏硅酸鈉粉體。 本論文還綜述了稻殼灰在不同領(lǐng)域中的應(yīng)用研究進展。稻殼灰最具發(fā)展前景的領(lǐng)域是火山灰材料和吸附劑。稻殼燃燒后形成的稻殼灰中含有大量無定形二氧化硅，這使得稻殼灰具有很好的火山灰活性，這不僅可以使制備出的混凝土具有高強度和高性能，還可以降低混凝土的生產(chǎn)成本。而且，稻殼灰中的二氧化硅和碳都具有一定的吸附能力，以稻殼灰為原料可以生產(chǎn)出高于其自身價值數(shù)倍的吸附劑。但是稻殼的燃燒條件對得到的稻殼灰的性能影響很大，因此研究如何獲得質(zhì)量穩(wěn)定并且性能理想的稻殼灰的燃燒條件是現(xiàn)在科研的重點。如果攻克了控溫這一難關(guān)，實現(xiàn)大規(guī)模化生產(chǎn)，一定會為稻殼灰在未來更多領(lǐng)域的發(fā)展開辟出嶄新的道路。 總之，稻殼灰是一種具有高效的、節(jié)能的、可持續(xù)發(fā)展的、有潛在環(huán)保價值、社會價值、經(jīng)濟價值的綠色原材料。稻殼灰擁有如此多的優(yōu)點使其在未來的研究中能夠為當(dāng)?shù)鼗蛘吒鄥^(qū)域的可持續(xù)發(fā)展提供新動力。
[Abstract]:With the increasing shortage of fossil resources and the increasing demand for energy, the global energy consumption increased from 4.04 脳 1017kW in 2001 to 6.40 脳 1017kW in 2025, an increase of 58kW. Therefore, the search for renewable and alternative energy resources has become an inevitable trend. China is a large agricultural country with large biomass production, low price and renewable biomass. The annual output of rice husk alone reaches 80 million tons. With the support of the national preferential policies, the technology of using rice husk to generate electricity has been popularized throughout the country. It has contributed to the utilization of straw resources and the alleviation of power tension in China. However, due to the influence of collection, transportation and price, it is very difficult to maintain business operations. At the same time, a large number of rice husk ash is not only a waste of resources, but also easily causes dust to pollute the environment. The comprehensive utilization of rice husk ash has important research value. In this paper, the silicon source of rice husk ash produced by pyrolysis was extracted and utilized. At first, silica and carbon were separated from rice husk ash by alkali solution, then sodium silicate solution and carbon were separated. Carbon was used as raw material of activated carbon. The effects of solid / liquid ratio, dissolution time, dissolution temperature and alkali concentration on the dissolution rate of silica were studied in detail, and the optimum reaction conditions were determined under the conditions of solid / liquid ratio of 1: 8, dissolution temperature of 100oC, dissolution time of 2.5 h / NaOH concentration of 10 wt%. The dissolution rate of silica can reach 93.26 wtand the modulus is 0.82. Then sodium metasilicate crystal containing crystalline water was prepared by liquid phase crystallization method using sodium silicate solution as raw material. The effects of solid content, solution modulus, crystallization temperature and seed on the crystal formation of sodium metasilicate were studied experimentally, and the effects of reaction conditions on the number of crystal water brought by sodium metasilicate were discussed. The experimental results show that different sodium metasilicate products can be successfully prepared from rice husk ash pretreated with acid by concentrated sodium silicate solution prepared by alkali solution and cooled and crystallized under different conditions. Sodium metasilicate pentahydrate can be prepared in the temperature range of 35oC, the modulus is 0.5-0.8, and the solid content is 45-55% sodium silicate solution cooled at room temperature. In the presence of seed, when the modulus is 0.7, the product is the first grade sodium metasilicate pentahydrate, and when the modulus is 0.8, The product was sodium metasilicate hexahydrate, and anhydrous sodium metasilicate powder was prepared by dehydration under 120oC. This paper also reviewed the application of rice husk ash in different fields. The most promising areas of rice husk ash are pozzolanic materials and adsorbents. The rice husk ash formed after burning contains a large amount of amorphous silica, which makes the rice husk ash have good pozzolanic activity, which can not only make the prepared concrete have high strength and high performance. It can also reduce the production cost of concrete. Moreover, silica and carbon in rice husk ash can be adsorbed to a certain extent, and the adsorbent which is several times higher than its own value can be produced by using rice husk ash as raw material. But the burning condition of rice husk has a great influence on the performance of rice husk ash, so it is the focus of scientific research to study how to obtain the burning condition of rice husk ash with stable quality and ideal performance. If we overcome the difficulty of temperature control and realize large-scale production, it will open a new way for the development of rice husk ash in more fields in the future. In a word, rice husk ash is a kind of green raw material with high efficiency, energy saving, sustainable development, potential environmental protection value, social value and economic value. Rice husk ash has so many advantages that it can provide new impetus for local or more regional sustainable development in future research.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ127.2
本文編號：2152603
[Abstract]:With the increasing shortage of fossil resources and the increasing demand for energy, the global energy consumption increased from 4.04 脳 1017kW in 2001 to 6.40 脳 1017kW in 2025, an increase of 58kW. Therefore, the search for renewable and alternative energy resources has become an inevitable trend. China is a large agricultural country with large biomass production, low price and renewable biomass. The annual output of rice husk alone reaches 80 million tons. With the support of the national preferential policies, the technology of using rice husk to generate electricity has been popularized throughout the country. It has contributed to the utilization of straw resources and the alleviation of power tension in China. However, due to the influence of collection, transportation and price, it is very difficult to maintain business operations. At the same time, a large number of rice husk ash is not only a waste of resources, but also easily causes dust to pollute the environment. The comprehensive utilization of rice husk ash has important research value. In this paper, the silicon source of rice husk ash produced by pyrolysis was extracted and utilized. At first, silica and carbon were separated from rice husk ash by alkali solution, then sodium silicate solution and carbon were separated. Carbon was used as raw material of activated carbon. The effects of solid / liquid ratio, dissolution time, dissolution temperature and alkali concentration on the dissolution rate of silica were studied in detail, and the optimum reaction conditions were determined under the conditions of solid / liquid ratio of 1: 8, dissolution temperature of 100oC, dissolution time of 2.5 h / NaOH concentration of 10 wt%. The dissolution rate of silica can reach 93.26 wtand the modulus is 0.82. Then sodium metasilicate crystal containing crystalline water was prepared by liquid phase crystallization method using sodium silicate solution as raw material. The effects of solid content, solution modulus, crystallization temperature and seed on the crystal formation of sodium metasilicate were studied experimentally, and the effects of reaction conditions on the number of crystal water brought by sodium metasilicate were discussed. The experimental results show that different sodium metasilicate products can be successfully prepared from rice husk ash pretreated with acid by concentrated sodium silicate solution prepared by alkali solution and cooled and crystallized under different conditions. Sodium metasilicate pentahydrate can be prepared in the temperature range of 35oC, the modulus is 0.5-0.8, and the solid content is 45-55% sodium silicate solution cooled at room temperature. In the presence of seed, when the modulus is 0.7, the product is the first grade sodium metasilicate pentahydrate, and when the modulus is 0.8, The product was sodium metasilicate hexahydrate, and anhydrous sodium metasilicate powder was prepared by dehydration under 120oC. This paper also reviewed the application of rice husk ash in different fields. The most promising areas of rice husk ash are pozzolanic materials and adsorbents. The rice husk ash formed after burning contains a large amount of amorphous silica, which makes the rice husk ash have good pozzolanic activity, which can not only make the prepared concrete have high strength and high performance. It can also reduce the production cost of concrete. Moreover, silica and carbon in rice husk ash can be adsorbed to a certain extent, and the adsorbent which is several times higher than its own value can be produced by using rice husk ash as raw material. But the burning condition of rice husk has a great influence on the performance of rice husk ash, so it is the focus of scientific research to study how to obtain the burning condition of rice husk ash with stable quality and ideal performance. If we overcome the difficulty of temperature control and realize large-scale production, it will open a new way for the development of rice husk ash in more fields in the future. In a word, rice husk ash is a kind of green raw material with high efficiency, energy saving, sustainable development, potential environmental protection value, social value and economic value. Rice husk ash has so many advantages that it can provide new impetus for local or more regional sustainable development in future research.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TQ127.2
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