Experimental research on the preparation of calcium aluminate by denitrification of secondary aluminum dross
The aluminum dross produced during the melting and casting process of aluminum and aluminum materials contains a large amount of alumina,which is an important secondary aluminum-containing resource.As a hazardous solid waste in the aluminum industry,aluminum dross can be converted into higher value products such as calcium aluminate and aluminum hydroxide.This paper utilizes secondary aluminum dross as raw material and calcium carbonate as a reagent to prepare calcium aluminate,investigating the influence of the calcium-to-aluminum mass ratio,holding time and baking tem-perature on the preparation process of calcium aluminate.The results show that when the calcium-to-aluminum mass ratio is 1.1~1.2,the holding time is 1.25~1.5 h and the baking temperature is 1 150~1 200℃,the mass fraction of C12A7 in the product is relatively high.The order of influence of various factors is that the calcium-to-aluminum mass ratio has a significant impact,followed by holding time,with baking temperature having the weakest effect.Under the conditions of a calcium-to-aluminum mass ratio of 1.2,holding time of 1.5 h and baking temperature of 1 150℃,calcium aluminate is prepared.The mass fraction of C12A7 in the product is 75.1%,with a small amount of magnesia-aluminum spinel and silicate.The solid-solid reaction mechanism of aluminum oxide and calcium carbonate in secondary aluminum dross is preliminarily discussed.
secondary aluminum drosscalcium aluminatecalcium-to-aluminum mass ratiobaking