本文選題：鎳渣 + 磁鐵礦相　； 參考：《蘭州理工大學(xué)》2017年碩士論文

【摘要】：鎳渣是鎳冶煉過程排放的一種工業(yè)廢渣,含有鐵、鎳、鈷、銅等多種有價(jià)金屬。為了實(shí)現(xiàn)鎳渣中鐵資源的高效回收再利用,本課題以金川公司閃速爐水淬鎳渣為研究對象,采用熔融改質(zhì)氧化的方法,通過加入氧化鈣對鎳渣進(jìn)行改質(zhì),通入空氣進(jìn)行弱氧化,控制降溫及保溫條件,使得鎳渣中鐵組元以磁鐵礦相的形式析出,然后通過磁選將磁性物質(zhì)與非磁性物質(zhì)分離。本文研究了鎳渣堿度、冷卻速率、保溫時(shí)間及保溫溫度對熔渣性能變化以及磁鐵礦相晶體形貌的影響規(guī)律,建立了磁鐵礦相析晶動(dòng)力學(xué)模型,探索熔融改質(zhì)鎳渣中磁鐵礦相的析出長大的行為。主要研究內(nèi)容及結(jié)果如下:(1)通過對鎳渣的成分及物相進(jìn)行分析得知,Fe含量約為39.91%,同時(shí)含有少量的Ni、Co、Cu等有價(jià)金屬。其中的主要物相為板條狀的鐵橄欖石相(Fe_2SiO_4)及鐵鎂橄欖石相[(Fe,Mg)SiO_4]。通過熔融改質(zhì)氧化的方法可以實(shí)現(xiàn)鎳渣中的鐵以磁鐵礦相(Fe_3O_4)的形式富集,且發(fā)現(xiàn)渣中的Ni、Co、Cu元素同時(shí)富集于磁鐵礦相中。(2)通過加入改質(zhì)劑氧化鈣(CaO),研究了堿度對熔融改質(zhì)鎳渣中磁鐵礦相析出與長大過程的影響規(guī)律。結(jié)果表明:適宜的堿度有利于磁鐵礦相的析出長大,當(dāng)堿度為0.6時(shí),渣中的主要物相為磁鐵礦相,呈不規(guī)則的顆粒狀,分布較為均勻,且結(jié)晶量最大,可達(dá)到36.3%。(3)研究溫控制度對磁鐵礦相析出與長大過程的影響。結(jié)果表明:隨著冷卻速率的減小,氧化渣樣中的物相組成沒有明顯變化,但磁鐵礦相的晶粒尺寸和結(jié)晶量都明顯增大,且晶體發(fā)育完整,晶界清晰,結(jié)合實(shí)際生產(chǎn)效率,冷卻速率在3~5℃/min較為適宜。保溫過程對磁鐵礦相析出長大過程影響顯著,隨著保溫時(shí)間的增長,熔渣長時(shí)間處于磁鐵礦相的結(jié)晶溫度范圍內(nèi),使磁鐵礦相有充分的時(shí)間析出長大,保溫20min時(shí),熔渣中磁鐵礦相充分析出;隨著保溫溫度的降低,磁鐵礦相的結(jié)晶量逐漸增大,說明適宜的過冷度有利于磁鐵礦相的析出,溫度為1350℃時(shí),磁鐵礦相析出效果較好;在1350~1400℃,磁鐵礦相等溫結(jié)晶動(dòng)力學(xué)過程可近似用JMAK經(jīng)驗(yàn)方程描述,并通過方程可求得晶體生長指數(shù)n≈0.5,析晶活化能E=-178.3kJ/mol。
[Abstract]:Nickel slag is a kind of industrial waste slag discharged from nickel smelting process. It contains many valuable metals such as iron, nickel, cobalt, copper and so on. In order to realize the high efficiency recovery and reuse of iron resource in nickel slag, this paper takes the water quenched nickel slag of Jinchuan company as the research object, adopts the method of melting modification and oxidation, by adding calcium oxide to the nickel slag to improve the quality of the nickel slag, and enters the air for weak oxidation. By controlling the cooling and holding conditions, the iron component in the nickel slag is precipitated in the form of magnetite phase, and then the magnetic material is separated from the non-magnetic material by magnetic separation. In this paper, the effects of basicity, cooling rate, holding time and holding temperature of nickel slag on the properties of molten slag and the crystal morphology of magnetite phase are studied, and the kinetic model of crystallization of magnetite phase is established. The precipitation and growth behavior of magnetite phase in molten modified nickel slag was investigated. The main research contents and results are as follows: (1) by analyzing the composition and phase of nickel slag, it is found that the content of Fe is about 39.91, and a small amount of valuable metals such as NiCoCoCU are also found. Among them, the main phases are plate stripe olivine phase Fes _ 2SiO _ 4) and ferric olivine phase [Fe _ 2O _ (2) Si _ 2O _ 4] and Fe _ (2) O _ (2) O _ (4) (Fe _ (2) O _ (2)). The iron in nickel slag can be enriched in the form of magnetite phase Fe _ 3O _ 4 by means of melting modification and oxidation. It is also found that the Ni _ (Co) Cu element in the slag is enriched in the magnetite phase at the same time.) the effect of alkalinity on the precipitation and growth of the magnetite phase in the molten modified nickel slag was studied by adding the modifier calcium oxide and Cao _ (2). The results show that the suitable basicity is favorable to the precipitation and growth of magnetite phase. When the basicity is 0.6, the main phase in slag is magnetite phase, which is irregular granular, and the distribution is more uniform, and the crystallization amount is the largest. The effect of temperature control system on the precipitation and growth of magnetite phase is studied. The results show that with the decrease of cooling rate, there is no obvious change in the phase composition of the oxidized slag, but the grain size and crystallization amount of the magnetite phase increase obviously, the crystal development is complete, the grain boundary is clear, and the production efficiency is combined with the actual production. The cooling rate is suitable at 5 鈩，

本文編號：1846814