發(fā)布時間：2018-06-04 14:54

  本文選題：磷石膏 + 水硬性膠凝材料　； 參考：《昆明理工大學》2015年碩士論文

【摘要】：磷石膏是工業(yè)濕法生產(chǎn)磷酸的副產(chǎn)物,其主要成分為CaSO4·2H2O,并含有P2O5、F-、有機物、微量重金屬以及其他的一些雜質(zhì)。目前,在全球范圍內(nèi),大約有15%的磷石膏作為資源被回收利用,主要應用在農(nóng)業(yè)、建材業(yè)和水泥緩凝劑等方面,但是,仍有85%的磷石膏作為固體廢物被堆放處理,不僅占用土地資源,而且會對周圍的環(huán)境造成嚴重的污染。經(jīng)過國內(nèi)外學者多年的研究,多集中于將磷石膏作為石膏板等石膏建材和磷石膏制硫酸聯(lián)產(chǎn)水泥工藝。磷石膏制硫酸聯(lián)產(chǎn)水泥工藝能將磷石膏變廢為寶,用于生產(chǎn)水泥熟料和硫酸,不但能夠大批量地利用磷石膏,減少其堆積和污染,而且能夠減少對石灰石原料和硫礦資源的開采,具有一定的環(huán)境和社會效益。但是在使用該工藝時,也存在著明顯的不足,在技術和經(jīng)濟效益方面還有許多問題亟待解決。從國內(nèi)外建成的磷石膏制硫酸聯(lián)產(chǎn)水泥工藝的生產(chǎn)線來看,主要存在著以下幾個方面的問題：一是磷石膏所含雜質(zhì)較多,原料成分變動較大,不易工業(yè)中的生產(chǎn)控制；二是熟料燒成溫度高,系統(tǒng)能耗大,回轉(zhuǎn)窯中容易結圈、粘結甚至堵塞,影響工藝的正常運行；三是生產(chǎn)出的熟料安定性差,質(zhì)量不穩(wěn)定。為了降低利用磷石膏燒制水泥熟料的能耗,解決磷石膏的分解和熟料的燒成等問題,本論文以磷石膏、活性炭和粉煤灰為主要原料,在1200℃低溫煅燒(相對于熟料的燒成溫度1450℃)的條件下,按照一定的配比進行混合煅燒,再將煅燒后的試樣同純硅酸鹽水泥熟料進行混合,制備出一種高性能煅燒高硅磷石膏基水泥。在煅燒過程中,磷石膏的分解產(chǎn)物CaO與粉煤灰中的SiO、Al2O3、Fe2O3等活性物質(zhì)反應生成各種有助于提高其硬化漿體強度的硅酸鹽礦物和鋁酸鹽礦物。適量的碳組分有助于在煅燒過程中形成還原氣氛,促進磷石膏的分解,而部分未分解的CaSO4還可以充當水泥緩凝劑,減少或不用外摻天然石膏,不但能夠提高水泥的強度,還能夠節(jié)約資源,帶來經(jīng)濟效益。本論文采用正交試驗的方法對制備高性能煅燒高硅磷石膏基水泥進行了探索研究。由于低溫煅燒制備磷石膏基水硬性膠凝材料中的礦物組成同普通硅酸鹽水泥熟料中的礦物組成存在著一定的差異,故在本正交試驗中以水硬系數(shù)(HM)來代替石灰飽和系數(shù)(KH)作為生產(chǎn)控制指標。在正交試驗中,以煅燒溫度、保溫時間、活性炭摻量和HM作為正交試驗的四個因素,對高性能煅燒高硅磷石膏基水泥的反應條件進行了研究。結果表明,當煅燒溫度為1200℃、保溫時間為30min、活性炭摻量為10%以及HM為13時,高性能煅燒高硅磷石膏基水泥的早期強度和后期強度都較高。在實際工業(yè)生產(chǎn)中.可以將HM作為主生產(chǎn)率值,SM作為輔助率值。本論文對正交試驗中抗壓強度典型試樣進行了XRD分析。結果表明,抗壓強度較高的試樣中普遍存在的活性礦物有硅酸三鈣(C3S)、硅酸二鈣(C2S)、鋁酸三鈣(C3A)、鋁酸二改(C2A)和鈣鋁黃長石(C2AS)等。其中,C3S和C3A的水化速度較快,對于硬化漿體的早期強度有著顯著的貢獻；在低溫煅燒條件下生成的 C2S,活性較高.水化速度正常,對于硬化漿體的早期強度和后期強度都有著較大的促進作用；C2A和C2AS屬于弱水硬性礦物,水化較慢,對于早期強度的提升無明顯貢獻,但對于后期強度有著一定的促進作用。本論文還通過XRD、SEM和EDS微觀分析手段對高性能煅燒高硅磷石膏基水泥的水化產(chǎn)物進行了研究分析。結果表明,硬化漿體主要由Ca(OH)2、C-S-H凝膠、水化鈣鋁黃長石(C2ASH8)、鈣礬石(AFt)以及水化氧化鋁凝膠組成,在整個結構中,以AFt作為網(wǎng)狀骨架,其中填充了大量的C-S-H凝膠和水化氧化鋁凝膠,形成了致密的結構,使得水泥的宏觀表現(xiàn)為抗壓強度高。本論文模擬了實際工業(yè)生產(chǎn)中的情況,采用等溫法對磷石膏—活性炭—粉煤灰體系進行了熱分解反應動力學的研究。將S03含量作為分解率的評價標準,對磷石膏—活性炭—粉煤灰體系的指前因子和表觀活化能進行了計算,確定了該體系的最概然機理函數(shù)。結果表明,磷石膏—活性炭—粉煤灰體系分解的表觀活化能為313.78～338.42KJ·mol-1,指前因子1nA為22.22～24.10s-1,最概然機理函數(shù)為代表隨機成核和隨后生長性質(zhì)的Avrami-Erofeev方程(n=2)。本論文對煅燒制備高性能煅燒高硅磷石膏基水泥時產(chǎn)生的煙氣量及其煙氣中SO2的含量進行了分析計算,并提出了一個合理的回收方案。結果表明,在煅燒制備高性能煅燒高硅磷石膏基水泥時,每生產(chǎn)1kg的熟料產(chǎn)生的煙氣量為1.11Nm3/kg,其中SO2的濃度為14.95%；同時通過分析表明,濕法有機胺脫硫技術,是一種新興的綠色煙氣脫硫工藝,其脫硫劑的循環(huán)再生利用,不但對環(huán)境的二次污染較少,而且能降低運營中的成本,設備簡單,操作流程簡便,具有較高的經(jīng)濟合理性和技術可行性,可以作為回收處理煅燒制備高性能煅燒高硅磷石膏基水泥時產(chǎn)生的SO2的方法。本論文針對了磷石膏目前難以得到有效資源化利用的現(xiàn)狀,提出了一種在低溫煅燒的條件下,制備高性能煅燒高硅磷石膏基水泥的方法。該法具有能耗低、設備簡單、操作簡便的特點,克服了傳統(tǒng)磷石膏制硫酸聯(lián)產(chǎn)水泥工藝中的種種不足,并從微觀和動力學角度闡釋了高性能煅燒高硅磷石膏基水泥高強的來源,完善了其制備的理論基礎,為下一步進行工業(yè)化應用和推廣奠定基礎。
[Abstract]:Phosphogypsum is a by-product of phosphoric acid production by industrial wet process. Its main component is CaSO4 2H2O, and contains P2O5, F-, organic matter, trace heavy metals and some other impurities. At present, around 15% of phosphogypsum is recycled as a resource worldwide. It is mainly used in agriculture, building materials industry and cement retarder. 85% of phosphogypsum is stacked as solid waste, not only occupying land resources, but also causing serious pollution to the surrounding environment. After years of research by scholars at home and abroad, most of them have concentrated phosphogypsum as plasterboard gypsum materials and phosphogypsum to produce sulphuric acid cement. The process of phosphogypsum to produce sulphuric acid cement can make phosphorus Gypsum is used in the production of cement clinker and sulfuric acid. It can not only use phosphogypsum in large quantities, reduce its accumulation and pollution, but also reduce the mining of limestone raw materials and sulphur resources. However, there are also obvious deficiencies in the use of the technology and the technical and economic benefits. There are many problems to be solved urgently. From the production line of phosphogypsum made by phosphogypsum made at home and abroad, there are main problems in the following aspects: one is that the impurities in the phosphogypsum are more, the composition of the raw material is changed, the production control in the industry is not easy, and the two is the high temperature of the clinker, the large energy consumption of the system and the rotation of the system. In the kiln, it is easy to ring, bond and even clog, which affects the normal operation of the process. Three is the poor stability and unstable quality of the produced clinker. In order to reduce the energy consumption of the cement clinker by using phosphogypsum, solve the decomposition of phosphogypsum and the burning of clinker, this paper uses phosphogypsum, activated carbon and fly ash as the main raw material, at 1200 C Under the conditions of low temperature calcining at a temperature of 1450 degrees centigrade, the calcined calcined samples were mixed with pure Portland cement clinker, and a high performance calcined high silicon phosphogypsum based cement was prepared. During the calcining process, the decomposed product CaO of phosphogypsum and SiO, Al2O3, Fe in the fly ash 2O3 and other active substances react to all kinds of silicate minerals and aluminate minerals that help to improve the strength of their hardened pulp. Proper amount of carbon components can help to form a reduction atmosphere during the calcination process and promote the decomposition of phosphogypsum, while some of the undecomposed CaSO4 can also act as a cement retarder, reducing or not adding natural gypsum. Not only can it be used to reduce or do not use natural gypsum. In this paper, the preparation of high performance calcined high silicon phosphogypsum based cement was studied by orthogonal test. The mineral composition of the phosphogypsum based cementitious material and the mineral composition in the common portland cement clinker by low temperature calcination was studied in this paper. In this orthogonal test, the water hardness coefficient (HM) is used to replace the lime saturation coefficient (KH) as the production control index in this orthogonal test. In the orthogonal test, the reaction conditions of high performance calcined high silicon phosphogypsum based cement are studied with calcining temperature, holding time, active carbon content and HM as four factors of orthogonal test. The results show that when the calcining temperature is 1200, the holding time is 30min, the amount of activated carbon is 10% and the HM is 13, the early strength and the later strength of high performance calcined high silicon phosphogypsum cement are high. In the actual industrial production, the HM can be used as the main productivity value and SM as the auxiliary ratio. The paper is typical of the compression strength in the orthogonal test. The samples were analyzed by XRD. The results showed that the common active minerals in the specimens with high compressive strength were three calcium silicate (C3S), two calcium silicate (C2S), three calcium aluminate (C3A), aluminum acid two (C2A) and calcium aluminum yellowish feldspar (C2AS). Among them, the hydration speed of C3S and C3A was faster, and the early strength of the hardened slurry was significantly reduced. The C2S produced under the temperature calcining condition has higher activity and normal hydration speed, which has a great promotion effect on the early strength and late strength of the hardened slurry; C2A and C2AS belong to the weak water hard mineral, and the hydration is slow, it has no obvious contribution to the early strength, but it has a certain promotion effect on the later strength. The hydration products of high performance calcined high silicon phosphogypsum based cement are studied by XRD, SEM and EDS microanalysis. The results show that the hardened slurry is composed mainly of Ca (OH) 2, C-S-H gel, calcium aluminum Huang Changshi (C2ASH8), ettringite (AFt) and hydrated aluminum oxide gel. In the whole structure, AFt is used as a reticular skeleton. A large number of C-S-H gels and hydrated alumina gel are filled to form a compact structure, which makes the macroscopic performance of the cement with high compressive strength. This paper simulates the situation in the actual industrial production and studies the kinetics of the thermal decomposition reaction of the phosphogypsum active carbon fly ash system by isothermal method. The content of S03 is taken as the decomposition of the system. The pre index and apparent activation energy of phosphogypsum active carbon fly ash system are calculated and the most probable mechanism function of the system is determined. The results show that the apparent activation energy of the decomposition of phosphogypsum active carbon fly ash system is 313.78 ~ 338.42KJ. Mol-1, the former factor 1nA is 22.22 ~ 24.10s-1, and the most probability is the most probability. The mechanism function is the Avrami-Erofeev equation (n=2), which represents the random nucleation and the subsequent growth properties. In this paper, the amount of flue gas and the content of SO2 in the flue gas produced by calcining high performance high silicon phosphogypsum based cement are analyzed and calculated, and a reasonable recovery scheme is put forward. The results show that the high performance calcinations are prepared by calcining. When high silicon phosphogypsum based cement is burned, the amount of flue gas produced by the clinker produced by 1kg is 1.11Nm3/kg, and the concentration of SO2 is 14.95%. At the same time, the analysis shows that wet organic amine desulphurization technology is a new green flue gas desulfurization technology. The recycle utilization of the desulfurizer not only reduces the two pollution of the environment, but also reduces the transport of the desulfurizer. The cost, simple equipment, simple operation process, high economic rationality and technical feasibility, can be used as a method to produce high performance calcined high silicon phosphogypsum based cement, which is produced by calcining and calcining. This paper aims at the present situation that phosphogypsum is difficult to be used in the utilization of phosphogypsum at present, and a kind of SO2 is put forward at low temperature. The high performance calcined high silicon phosphogypsum based cement is prepared under the conditions of calcining. This method has the characteristics of low energy consumption, simple equipment and easy operation. It overcomes the shortcomings of the traditional phosphogypsum system of sulphuric acid producing cement, and explains the source of high performance calcined high silicon phosphogypsum cement high strength from the micro and dynamic angles. The theoretical basis of its preparation is well established, laying the foundation for further industrial application and popularization.
【學位授予單位】：昆明理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ172.1

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本文編號：1977786