(中南大學(xué) 冶金與環(huán)境學(xué)院，長(zhǎng)沙 410083)
摘 要: 為緩解我國(guó)氧化鋁工業(yè)存在的鋁土礦需求量大與國(guó)內(nèi)鋁土礦供應(yīng)嚴(yán)重不足間的矛盾和粉煤灰大量堆積造成的環(huán)境問(wèn)題，基于粉煤灰還原-氧化焙燒-堿浸實(shí)現(xiàn)鋁硅分離的全新工藝路線，在已有靜態(tài)小實(shí)驗(yàn)基礎(chǔ)上，開展了實(shí)驗(yàn)室回轉(zhuǎn)窯動(dòng)態(tài)擴(kuò)大試驗(yàn)研究。結(jié)果表明：在1100 ℃、配料比n(Fe):n(Al):n(C)=1.2:2:1.2、進(jìn)料量75 g、還原焙燒1 h條件下得到的焙燒熟料，在Na2O濃度為77.5 g/L的NaOH溶液中、液固比為20 mL/g時(shí)在130 ℃下溶出60 min，熟料中硅溶出率達(dá)92%；在Na2O濃度100 g/L、模數(shù)為1.0的硅酸鈉溶液中130 ℃溶出2 h，硅溶出率達(dá)60%以上，獲得模數(shù)為2.4的硅酸鈉溶液。對(duì)比分析物料焙燒過(guò)程和熟料溶出前后的形貌、粒度變化情況表明，物料粒度較大和溶液結(jié)構(gòu)變化將導(dǎo)致硅溶出率下降。
關(guān)鍵字: 粉煤灰；方石英；鋁酸亞鐵；還原焙燒；鋁硅分離
（School of Metallurgy and Environment, Central South University, Changsha 410083, China）
Abstract:To alleviate the contradiction between the large bauxite demand and the serious shortage of bauxite supply in China''''s alumina industry and solve the environmental problems caused by the massive accumulation of coal fly ash, the laboratory rotary kiln experimental study was carried out based on the proposed process of coal fly ash reduction-oxidation roasting-alkali leaching through the small static experiments. The results show that the clinker are obtained under the conditions of 1100 ℃, n(Fe):n(Al):n(C)=1.2:2:1.2 of the raw materials, the feeding amount of 75 g and reduction roasting residence of 1 h. When it is dissolved in caustic soda solution with Na2O concentration 77.5 g/L and the liquid-solid ratio of 20 mL/g at 130 ℃ for 60 min, the dissolution rate of silicon can reach 92%. While the sodium silicate solution with Na2O concentration of 100 g/L and modulus of 1.0 was used as the leaching agent, the silicon dissolution rate can reach more than 60% at 130 ℃ for 2 h, and the sodium silicate solution with modulus of 2.4 is obtained. Furthermore, the morphology and particle size changes of the materials during the roasting and dissolution processes were analyzed. The results indicate that the coarse particles and solution structure change will result in the reduction of the dissolution rate of silicon.
Key words: coal fly ash; cristobalite; hercynite; reduction roasting; separation of aluminum and silicon
