(1. 中南大學(xué) 冶金與環(huán)境學(xué)院，長沙 410083；
2. 貴陽鋁鎂設(shè)計(jì)研究院，貴陽 550004)
摘 要: 通過分析含硅鋁酸鈉溶液脫硅過程二氧化硅濃度、脫硅渣成分和物相，研究氧化鎂在鋁酸鈉溶液中的反應(yīng)行為。結(jié)果表明，在95~100 ℃的常壓脫硅條件下，氧化鎂在鋁酸鈉溶液中易形成水合碳鋁酸鎂，對溶液基本無脫硅效果，氧化鋁損失較多，但氧化鎂能顯著促進(jìn)石灰的脫硅作用，且在石灰用量一定時(shí)隨氧化鎂添加量的增加，溶液的脫硅率顯著升高；在190 ℃的高壓脫硅條件下，氧化鎂對鋁酸鈉溶液石灰脫硅作用的促進(jìn)不明顯，但它可使脫硅渣的鈉硅比(質(zhì)量比)顯著降低；無論是單獨(dú)采用石灰(CaO)，還是采用石灰和氧化鎂混和物脫硅，含硅鋁酸鈉溶液高溫脫硅渣中均含有鈉硅渣相，這與熱力學(xué)分析結(jié)果一致。
關(guān)鍵字: 氧化鎂；鋁酸鈉；石灰；脫硅；鈉硅渣
（1. School of Metallurgy and Environment, Central South University, Changsha 410083, China;
2. Guiyang Aluminum and Magnesium Design and Research Institute, Guiyang 550004, China）
Abstract:The reaction behavior of MgO in the desilication process of sodium aluminate solution was studied by analyzing SiO2 concentration variation in solution and compositions and phases of the desilication slag. The results indicate that under desilication conditions of 95-100 ℃ and normal pressure, MgO can react with SiO2-containing sodium aluminate solution to form the magnesium hydroaluminocarbonate and cause the loss of alumina. MgO has almost no desilication effect in the normal pressure desilication process, but it can promote the desilication rate of CaO significantly and the desilication rate increases with the increase of MgO amount when the dosage of CaO is constant. Under desilication conditions of 190 ℃ and high pressure, MgO has little effect on the desilication rate of CaO, but it can decrease the mass ratio of soda to silica of desilication slag. The sodium aluminosilicate hydrate is one of the main phases of the slags produced from high temperature desilication process with either MgO or mixture of MgO and CaO as desilication agent, which agrees with the result of thermodynamic calculation.
Key words: magnesium oxide; sodium aluminate; lime; desilication; sodium aluminosilicate hydrate
