本文關(guān)鍵詞： 有機硅烷 黃鐵礦 表面鈍化 酸性礦山廢水　出處：《湘潭大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：黃鐵礦是最為常見的金屬硫化物礦物,廣泛存在于各種尾礦、廢石堆和有價值的原礦中。在自然環(huán)境中,黃鐵礦容易發(fā)生氧化反應(yīng)導(dǎo)致酸性礦山廢水(AMD)污染,進而威脅人類的健康安全。為了從源頭上控制AMD的產(chǎn)生,本論文采用電化學(xué)技術(shù)和傳統(tǒng)的化學(xué)浸取法相結(jié)合,篩選出合適的有機硅烷鈍化劑,并探討有機硅烷鈍化黃鐵礦的效果和機理,得到有價值的結(jié)果主要有:實驗選用的三種有機硅烷鈍化劑:氨丙基三甲氧基硅烷(APS)、乙烯基三甲氧基硅烷(VTMS)和巰丙基三甲氧基硅烷(PropS-SH)均能在一定程度上抑制黃鐵礦電極的陽極反應(yīng)。循環(huán)伏安(CV)、極化曲線(Tafel)和交流阻抗譜圖(EIS)結(jié)果表明,經(jīng)過有機硅烷鈍化后的黃鐵礦相對于黃鐵礦原礦的表面電化學(xué)行為明顯減弱,腐蝕電流密度減小,表面膜阻抗顯著增大。說明所選擇的三種有機硅烷均能夠在黃鐵礦表面進行包膜,從而有效的抑制黃鐵礦的電化學(xué)行為。在化學(xué)浸取實驗中,經(jīng)APS、VTMS和PropS-SH鈍化后的黃鐵礦的總鐵浸出抑制率分別為49.4%、71.4%和89.2%;硫酸根離子的浸出抑制率分別達到45.1%、69.1%和89.6%。電化學(xué)和化學(xué)浸取的實驗結(jié)果表明APS、VTMS和PropS-SH鈍化劑既能在一定程度上抑制黃鐵礦的電化學(xué)氧化,還能阻礙或減緩黃鐵礦的化學(xué)氧化,且都證明了三種有機硅烷對黃鐵礦的鈍化強度為:PropS-SHVTMSAPS。因此,通過電化學(xué)手段和化學(xué)浸取實驗初步篩選出鈍化效果最好的鈍化劑為PropS-SH。為進一步確定PropS-SH處理黃鐵礦的最佳鈍化條件,本文研究包膜過程中不同因素對包膜后黃鐵礦鈍化效果的影響。結(jié)果表明,PropS-SH處理黃鐵礦的最佳鈍化條件為:硅烷濃度為10%;溶液pH為4.0;硅烷水解時間為4 h;硅烷水解溫度為40℃。在最佳的鈍化條件下,進行為期4個月的淋濾實驗以評價鈍化后黃鐵礦的長期穩(wěn)定性。實驗結(jié)果顯示,黃鐵礦表面的PropS-SH鈍化膜在一定時期內(nèi),有很好的抗氧化能力,能夠阻隔黃鐵礦與環(huán)境中的水、氧氣及細菌的接觸,減緩黃鐵礦表面所發(fā)生的氧化反應(yīng),從而減少酸性廢水的產(chǎn)生,有一定的實際應(yīng)用價值。最后,本文采用粉末接觸角法和自然吸水率法對PropS-SH鈍化后的黃鐵礦進行潤濕性實驗。結(jié)果表明:PropS-SH鈍化后黃鐵礦的接觸角相對于黃鐵礦原礦增大89.64°,表明其表面疏水性得到顯著提高;自然吸水率實驗表明PropS-SH鈍化后黃鐵礦的自然吸水率已不足0.01%。FT-IR和XPS分析結(jié)果顯示,PropS-SH在黃鐵礦表面鈍化的機制是已經(jīng)水解好的有機硅烷與黃鐵礦表面的羥基發(fā)生交聯(lián)反應(yīng),在黃鐵礦表面形成Fe-O-Si化學(xué)鍵,而溶液中硅烷分子相互發(fā)生縮聚反應(yīng),生成以Si-O-Si為骨架的網(wǎng)狀結(jié)構(gòu)。
[Abstract]:Pyrite is the most common metallic sulphide mineral, widely found in various tailings, waste rock piles and valuable raw ores. In the natural environment, pyrite is prone to oxidize and lead to acid mine wastewater (AMD) pollution. In order to control the production of AMD from the source, this paper combines the electrochemical technology with the traditional chemical leaching method to screen the suitable organosilane passivating agent. The effect and mechanism of organosilane passivating pyrite are also discussed. The results are as follows: the three kinds of organosilane passivating agents used in the experiment, namely, aminopropyltrimethoxysilane, vinyltrimethoxy silane and mercapto trimethoxysilane propS-SH, can inhibit Huang Tie to a certain extent. Anodic reaction of ore electrodes. The results of cyclic voltammetry (CV), polarization curve (Tafel) and impedance spectroscopy (EIS) show that, The surface electrochemical behavior of pyrite passivated by organosilane was obviously weakened and the corrosion current density was decreased. The impedance of the surface film increases significantly. The results show that all of the three organosilanes selected can be coated on the surface of pyrite, which effectively inhibits the electrochemical behavior of pyrite. The total iron leaching inhibition rates of pyrite passivated by PropS-SH and PropS-SH were 49.4% and 89.2%, respectively, and the inhibition rates of sulphate ion leaching were 45.1% and 89.6%, respectively. The results of electrochemical and chemical leaching showed that PropS-SH passivator and APSV TMS could be used for a certain period of time. To inhibit the electrochemical oxidation of pyrite, It can also block or slow down the chemical oxidation of pyrite, and all of them prove that the passivation intensity of three kinds of organosilane to pyrite is 1: PropS-SHV TMSAPS. therefore, By electrochemical means and chemical leaching experiments, the best passivating agent is PropS-SH.The best passivation condition for pyrite treatment by PropS-SH is determined. The effect of different factors on the passivation effect of pyrite after coating was studied in this paper. The results show that the optimal passivation conditions for pyrite treated by PropS-SH are as follows: concentration of silane is 10; pH value of solution is 4.0; hydrolysis time of silane is 4 hours; water of silane is treated with water. The decomposition temperature is 40 鈩，

本文編號：1508398