本文選題：鋼渣 + 多孔吸聲材料　； 參考：《北京科技大學》2016年博士論文

【摘要】：鋼渣是鋼鐵生產過程排放最多的固體廢棄物,具有成分復雜、耐磨和安定性差等特性,致使我國鋼渣資源化利用率低,環(huán)境污染嚴重。鋼渣含有部分硅酸鹽成分,具有一定的膠凝活性,可用作水泥、陶瓷、玻璃等建材生產的原料。目前噪聲污染日益嚴重、噪聲污染治理越發(fā)緊迫,而采用多孔陶瓷、泡沫玻璃等新型無機非金屬材料吸聲降噪越來越受到重視。因此,探索利用鋼渣制備多孔吸聲材料,開發(fā)鋼渣資源化利用的新途徑和新領域,提高鋼渣利用率,對企業(yè)節(jié)約資源、保護環(huán)境、提高經(jīng)濟效益具有重要意義。論文選擇高溫燒結的方法制備鋼渣吸聲材料,針對關鍵材料參數(shù)和性能指標,逐步改進原料配方及相應的成型造孔工藝。通過對比鋼渣-粉煤灰、鋼渣-粘土-長石-石英體系和鋼渣-粉煤灰-粘土-稻殼灰三個體系原料配方及其相應成型造孔方法的特點,確定了制備工藝方案,并探討了制備機理,建立了燒結過程模型。論文主要得到如下結論：(1)本研究采用的轉爐鋼渣主要化學組成為CaO、Fe2O3、SiO2,Al2O3、 MgO等；主要礦物相為C2S、C3S、RO目、C2F和C3A等。冷態(tài)制備的鋼渣膠凝材料早期強度低,28天強度為18.36MPa,而高溫燒結試樣抗壓強度可達90.86MPa。相對于冷態(tài)制備方法,選擇高溫燒結的方法制備鋼渣多孔吸聲材料將能夠具有更好的力學性能。(2)通過摻加不同硅質材料改進原料配方,不但可以獲得較好的力學性能也可逐步拓寬燒成溫度范圍；而通過調整造孔劑種類、添加方式及成型造孔方法,可提高鋼渣吸聲材料的孔隙率,并保持較好的力學性能。采用三種基體材料配方及相應成型造孔方法制備的鋼渣吸聲材料孔隙率在50%以上,抗壓性能可達3.0MPa以上,厚度在2.5-3.0mm的材料平均吸聲系數(shù)可達到0.40-0.48。鋼渣-粉煤灰-粘土-稻殼灰體系及顆粒堆壓與造孔劑復合造孔方法廢物利用率高、工藝簡單、燒成溫度范圍較寬,以及材料力學和吸聲性能較好,因此,選擇該原料配方和成型方法作為鋼渣多孔吸聲材料的制備工藝。制備工藝條件包括：鋼渣：粉煤灰：粘土：稻殼灰的配比為12：3：2：3,高溫造孔劑為白云石摻加量基體材料質量的10%；圓盤造粒的顆粒粒徑控制在1.2-2.8mm；顆粒堆壓在1.0-1.5MPa之間；燒成溫度區(qū)間在1130-1180℃,較適宜的燒結溫度和時間為1150℃和4h。(3)通過鋼渣多孔吸聲材料燒結成孔機理研究發(fā)現(xiàn),稻殼灰、白云石可作造孔劑也是良好的摻加劑,適當燒結溫度下坯體孔隙率均在50%以上,而且抗折強度最大可達44.7MPa。在控制燒成溫度方面,稻殼灰、白云石和長石等原料的摻加可以改變燒結反應的溫度,稻殼灰和長石分別可以降低反應溫度20-30℃和10℃左右,但同時也縮短了燒成溫度區(qū)間；白云石可以拓寬燒成溫度范圍,卻提高了燒結反應的溫度。因此,應控制稻殼灰和白云石的摻加量,該配方不宜摻加長石。燒結溫度是鋼渣吸聲材料制備的主要影響因素。材料造孔過程主要在低溫階段,燒結升溫速率不宜過快；燒結反應主要發(fā)生在高溫階段。延長燒結時間可促進燒結反應,使晶體充分發(fā)育生長,材料獲得良好的力學性能,但同時降低孔隙率而影響吸聲性能,燒結時間宜控制在2.5-4.0h。提高成型壓力增加坯體密實度,可促進燒結反應,也使孔隙率明顯降低；成型壓力較低的試樣具有較高孔隙率,但致密化程度低,因而成型壓力可在1.0-1.5MPa之間。(4)多孔材料燒結過程可分為初期、中期和后期三個階段,造孔劑分解造孔和燒結反應兩個過程。燒結初期大約在室溫到1100℃,燒結反應緩慢,收縮率在1%左右,少量中間過渡礦相鈣鐵榴石產生,主要是多孔材料的造孔過程。燒結中期在1100-1150℃之間,燒結收縮加速,收縮率達5%左右,主要表現(xiàn)為燒結頸部擴大,氣孔形狀改變,孔隙率下降；礦物相逐步從過渡礦物相生成穩(wěn)定的透輝石相和少量RO相。燒結后期在1150-1200℃之間,收縮率達到10%以上,是孔隙形態(tài)、大小和數(shù)量快速變化的過程,也是晶體形成、生長,生成穩(wěn)定礦物相的過程；由于大量高溫液相產生,傳質方式發(fā)生改變。燒結中期和后期組成材料燒結的另一個過程,即燒結反應的主要過程。燒結動力學結果表明,隨燒結溫度提高,坯體的燒結速率常數(shù)快速增加；燒結時間關系指數(shù)n值逐步由0.221升至0.342,說明坯體內的傳質從表面擴散逐步變化為品界擴散的過程,在1190℃時n值下降為0.195,坯體中已有液相產生,傳質方式已經(jīng)改變；在1150-1190℃的活化能為32.88 kJ/mol。(5)鋼渣多孔材料孔隙率、平均孔徑、厚度和體積密度對吸聲性能具有明顯的影響。提高材料的孔隙率、增加材料厚度、孔徑增大、減小體積密度均可提高材料平均吸聲系數(shù),尤其是增加材料厚度對于提高低頻吸聲系數(shù)作用效果顯著,當增加到5.1cm時,平均吸聲系數(shù)達到0.55。與其他常用多孔吸聲材料性能比較發(fā)現(xiàn),厚度基本相同條件下,鋼渣多孔吸聲材料的吸聲性能優(yōu)于多數(shù)常用的吸聲材料；換算成混響室法吸聲系數(shù)為0.74,吸聲性能為Ⅱ級,屬于具有優(yōu)良的吸聲性能吸聲產品。
[Abstract]:Steel slag is the most discharged solid waste in the process of iron and steel production. It has the characteristics of complex composition, poor wear resistance and poor stability, which causes low utilization rate of steel slag and serious environmental pollution in China. Steel slag contains some silicate components and has certain gelation activity, which can be used as raw materials for building materials such as water mud, ceramics and glass. The treatment of noise pollution is becoming more and more urgent, and the sound absorption and noise reduction of new inorganic nonmetallic materials, such as porous ceramics and foam glass, are being paid more and more attention. Therefore, the exploration and use of steel slag to prepare porous sound absorption materials, develop new ways and new domain for utilization of steel slag, improve the utilization rate of steel slag, save resources and protect enterprises. Environment, improving economic benefit is of great significance. This paper chooses high temperature sintering method to prepare steel slag sound absorption material. According to key material parameters and performance indexes, the raw material formula and corresponding molding process are gradually improved. By comparing steel slag fly ash, steel slag clay feldspar quartz system and steel slag - fly ash - clay - rice husk ash three On the basis of the characteristics of the system material formula and its corresponding molding method, the preparation process is determined, the mechanism of preparation and the sintering process model are discussed. The main conclusions are as follows: (1) the main chemical composition of converter steel slag used in this study is CaO, Fe2O3, SiO2, Al2O3, MgO and so on. The main mineral phases are C2S, C3S, RO, C2F and C. 3A et al. The early strength of steel slag cementitious material prepared by cold state is low, the strength of 28 days is 18.36MPa, and the compressive strength of the high temperature sintered sample can reach 90.86MPa. relative to the cold state preparation method. The choice of high temperature sintering method to prepare the porous sound absorbing material of steel slag will have better mechanical properties. (2) improving the raw material formula by adding different siliceous materials. It can not only obtain better mechanical properties but also gradually broaden the range of sintering temperature, and by adjusting the types of pore making agents, adding methods and forming hole making methods, the porosity of the steel slag absorbing materials can be improved and the mechanical properties are maintained. Three kinds of matrix material formula and the corresponding molding hole making method are used to make steel slag absorbing materials. The porosity is above 50% and the compression performance is above 3.0MPa. The average sound absorption coefficient of material with thickness of 2.5-3.0mm can reach 0.40-0.48. steel slag - fly ash - clay - rice husk ash system and the compound hole making method of pore pressure and pore making agent, which has high utilization rate, simple process, wide firing temperature range, and good mechanical and sound absorption properties of materials. Therefore, the preparation process of the raw material formula and molding method is selected as the preparation process of the porous sound absorption material of steel slag. The preparation conditions include: steel slag: Fly Ash: Clay: the ratio of clay: the ratio of the rice husk ash is 12:3:2:3, the high temperature pore making agent is 10% of the mass of the dolomite, and the particle size of the disc granulation is controlled in 1.2-2.8mm; The pile pressure is between 1.0-1.5MPa, and the sintering temperature range is 1130-1180, and the suitable sintering temperature and time is 1150 and 4h. (3) through the porous sound absorption material of steel slag. It is found that the rice husk ash, dolomite can be a good additive, and the porosity of the body is above 50% under proper sintering temperature, and the bending resistance is more than 50%. With the maximum strength of 44.7MPa., the addition of rice husk ash, dolomite and feldspar can change the temperature of the sintering reaction. The rice husk ash and feldspar can reduce the reaction temperature of 20-30 and 10, but also shorten the firing temperature range, but the dolomite can broaden the firing temperature range, but increase the temperature range. The sintering temperature is not suitable for adding feldspar. The sintering temperature is the main factor affecting the preparation of the sound-absorbing material of steel slag. The process of making holes in the material is mainly at the low temperature stage, and the heating rate should not be too fast; the sintering reaction is mainly in the high temperature stage. The prolonging of the sintering time can be promoted. The sintering reaction makes the crystal fully develop and grow, and the material obtains good mechanical properties, but it reduces the porosity at the same time and affects the sound absorption performance. The sintering time should be controlled in 2.5-4.0h. to increase the forming pressure to increase the density of the body, to promote the sintering reaction, and to reduce the porosity obviously, and the specimen with lower molding pressure has a higher porosity. But the densification degree is low, thus the forming pressure can be between 1.0-1.5MPa. (4) the sintering process of porous materials can be divided into three stages, in the early stage, in the middle and later stages. The pore forming agent is divided into two processes. The initial sintering process is about at room temperature to 1100 C, the sintering reaction is slow, the shrinkage rate is about 1%, and a small amount of intermediate transition ore phase calcite In the middle period of sintering, the sintering shrinkage accelerated and the shrinkage rate was about 5%. The main performance was the enlargement of the sintered neck, the shape of the pores, the decrease of porosity, and the gradual formation of a stable diopter phase and a small amount of RO phase from the mineral phase. The later period of sintering was between 1150-1200 and 1150-1200. The shrinkage rate is over 10%, which is the process of rapid change in pore shape, size and quantity. It is also the process of crystal formation, growth, and formation of stable mineral phase; the mass transfer mode changes due to the production of a large number of high temperature liquid phases. The other process of sintering at the middle and later stages of sintering, the main process of sintering reaction, is the sintering kinetics. The results show that the sintering rate constant increases rapidly with the increase of sintering temperature, and the n value of the sintering time relationship exponentially increases from 0.221 to 0.342, indicating that the mass transfer in the body is gradually changed from the surface diffusion to the process of the boundary diffusion, and the n value decreases to 0.195 at 1190. The mass transfer mode has been changed, and the mass transfer mode has been changed at 11. The activation energy of 50-1190 C is 32.88 kJ/mol. (5) porous material, the average pore size, thickness and volume density have obvious influence on the sound absorption properties. Increasing the porosity, increasing the material thickness, increasing the pore size and reducing the volume density can increase the average sound absorption coefficient of the material, especially increasing the thickness of the material to improve the low frequency. The effect of sound absorption coefficient is remarkable. When increasing to 5.1cm, the average sound absorption coefficient reaches 0.55. and compared with other commonly used porous sound absorbing materials. Under the same thickness, the sound absorption properties of the porous material for steel slag are better than that of most commonly used sound absorption materials, and the sound absorption coefficient of the reverberation chamber method is 0.74 and the sound absorption performance is class II. It is a sound absorption product with excellent sound absorption properties.
【學位授予單位】：北京科技大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：X757;TB535

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相關期刊論文 前1條

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本文編號：2028113