本文關(guān)鍵詞： 磷礦石 直接還原 還原率 助熔劑 還原動力學(xué)　出處：《鄭州大學(xué)》2011年碩士論文　論文類型：學(xué)位論文

【摘要】：磷酸是制備精細(xì)磷酸鹽和磷復(fù)肥等磷化工產(chǎn)品的基本原料,在工農(nóng)業(yè)和國防軍工以及電子等尖端科學(xué)領(lǐng)域都有著廣泛的應(yīng)用。目前,生產(chǎn)磷酸的工業(yè)方法主要有三種：濕法磷酸、熱法磷酸、窯法磷酸,各種磷酸制備的工業(yè)方法都存在著不同的原料適應(yīng)性、能耗水平、環(huán)境影響和產(chǎn)品純度。 本課題研究力圖探尋一種原料適應(yīng)性廣、能耗水平較低、環(huán)境影響小和產(chǎn)品純度高的磷酸制備新工藝-高爐法磷酸工藝,利用焦炭(或無煙煤)為燃料,磷礦和熔劑為原料,在高爐中高溫熔融,磷礦中的磷元素以單質(zhì)磷蒸氣形式還原,同時熔融物水淬冷凝制備低磷中量營養(yǎng)元素(硅、鈣、鎂)肥料,或分離稀有貴重金屬(鎳、鈦)等,因此本課題研究對實現(xiàn)磷資源,尤其是低品位磷資源的全面合理綜合利用,提高磷酸工業(yè)技術(shù)水平具有一定的意義。主要研究內(nèi)容及結(jié)論如下： (1)分析了影響磷礦還原的各種因素(還原時間、還原溫度、硅鈣比),確定了磷礦還原過程的優(yōu)惠工藝條件。研究表明：在磷礦還原過程中,反應(yīng)溫度是影響磷礦還原率的重要因素,反應(yīng)溫度越高還原速度越快,還原所需的間越短；硅鈣比也是影響磷礦還原的另一個重要因素,隨著硅鈣摩爾比增大,還原率增加。綜合考慮,硅鈣摩爾比選取0.8-1.0之間比較適宜。磷礦隨反應(yīng)時間的變化率在1200℃時很小,但當(dāng)升高溫度到1300℃-1500℃時,磷礦隨反應(yīng)時間的轉(zhuǎn)化速率比較大,且具有一定的規(guī)律性。 (2)分析了爐渣中的化學(xué)組分對于爐渣熔點的影響,確定NaCl和KC1作為助熔劑。通過研究加入NaCl和KCl后對磷礦還原率的影響,發(fā)現(xiàn)兩種熔劑均有利于促進(jìn)磷礦還原率的提升,KC1比NaCl作為助熔劑的作用更為明顯,其增長幅度在1%-10%之間；加入量高(10%)或加入量低(5%)時磷礦還原增長幅度并不明顯,加入量在5%-7%范圍內(nèi)最好。 (3)探討了磷礦還原過程反應(yīng)特性及還原機(jī)理。認(rèn)為：磷礦首先與二氧化硅進(jìn)行脫氟反應(yīng)而生成2CaF2·SiO2和Ca3 (PO4) 2,生成的Ca3(P04)2通過擴(kuò)散反應(yīng)通過熔融液相擴(kuò)散致焦炭表面進(jìn)行還原的。假定在高溫下還原反應(yīng)主要受擴(kuò)散控制,基于此假設(shè)對還原過程進(jìn)行了動力學(xué)實驗,確定了還原學(xué)動力學(xué)模型,并擬合出速率常數(shù)K,為工業(yè)化生產(chǎn)提供了必要的基礎(chǔ)理論數(shù)據(jù)。
[Abstract]:Phosphoric acid is the basic raw material for the preparation of fine phosphate and phosphate compound fertilizer, which is widely used in the fields of industry, agriculture, national defense, military industry, electronics and so on. There are three main industrial methods for producing phosphoric acid:. The industrial methods of preparation of wet phosphoric acid, thermal phosphoric acid, kiln phosphoric acid and various phosphoric acid have different feedstock adaptability, energy consumption level, environmental impact and product purity. This paper tries to explore a new phosphoric acid preparation process with wide adaptability of raw materials, low energy consumption, low environmental impact and high purity of product, which is made of coke (or anthracite) as fuel. Phosphate rock and flux are used as raw materials in blast furnace melting at high temperature, phosphorus element in phosphate rock is reduced in the form of simple phosphorus vapor, and melt material is quenched and condensed to produce low phosphorus medium nutrient fertilizer (silicon, calcium, magnesium). Or the separation of rare and precious metals (nickel, titanium) and so on, so this study on the realization of phosphorus resources, especially the comprehensive utilization of low-grade phosphorus resources. It is of certain significance to improve the technological level of phosphoric acid industry. The main research contents and conclusions are as follows: 1) various factors affecting the reduction of phosphate rock (reduction time, reduction temperature, ratio of silica to calcium) are analyzed, and the preferential technological conditions of the process of phosphate rock reduction are determined. The results show that: in the process of phosphate rock reduction. The reaction temperature is an important factor affecting the reduction rate of phosphate rock. The higher the reaction temperature, the faster the reduction rate, the shorter the time required for reduction. The ratio of silica to calcium is another important factor affecting the reduction of phosphate rock. With the increase of the molar ratio of silica to calcium, the reduction rate increases. The change rate of phosphate rock with reaction time is very small at 1200 鈩，

本文編號：1486877