Red mud(RM)is a solid waste generated from the extraction of alumina from bauxite.It is estimated that more than1.5 billion tonnes of RM are produced annually worldwide.Stockpiling and landfilling of RM is toxic for t...Red mud(RM)is a solid waste generated from the extraction of alumina from bauxite.It is estimated that more than1.5 billion tonnes of RM are produced annually worldwide.Stockpiling and landfilling of RM is toxic for the environment due to the presence of high quantities of alkali-generating minerals and metal ions.The high cost of RM treatment and limited land availability encourage the recycling and reuse of RM as construction materials.In many developing countries,brick remains the ubiquitous building material.Thus,it is reasonable to use brick as a medium to accommodate a large amount of RM.In this review,the properties of RM are analyzed and their applications in bricks are discussed.Two common types of RM,namely Bayer red mud(BRM)and sintering red mud(SRM),are introduced along with the methods to produce bricks from them through firing,cementing,and geopolymerization.High alkaline-based BRM is particularly useful as a raw material to produce fired brick and geopolymer brick,whereas SRM,which contains more dicalcium silicate(C_(2)S)and some cementitious phases,can be favorably used to produce cementing brick.RM geopolymer brick normally has more strength(up to 51 MPa)than fired and cementing bricks,and good durability(no efflorescence)with low energy consumption and CO_(2)emissions.Finally,several solutions have been suggested to resolve the issue of the radioactivity of RM brick,and strict regulation of its application has been imposed in some countries,such as China.展开更多
基金supported by the Hunan Provincial Program for Innovative Talents of Excellent Postdoctoral Fellow(No.2020RC2031),China。
文摘Red mud(RM)is a solid waste generated from the extraction of alumina from bauxite.It is estimated that more than1.5 billion tonnes of RM are produced annually worldwide.Stockpiling and landfilling of RM is toxic for the environment due to the presence of high quantities of alkali-generating minerals and metal ions.The high cost of RM treatment and limited land availability encourage the recycling and reuse of RM as construction materials.In many developing countries,brick remains the ubiquitous building material.Thus,it is reasonable to use brick as a medium to accommodate a large amount of RM.In this review,the properties of RM are analyzed and their applications in bricks are discussed.Two common types of RM,namely Bayer red mud(BRM)and sintering red mud(SRM),are introduced along with the methods to produce bricks from them through firing,cementing,and geopolymerization.High alkaline-based BRM is particularly useful as a raw material to produce fired brick and geopolymer brick,whereas SRM,which contains more dicalcium silicate(C_(2)S)and some cementitious phases,can be favorably used to produce cementing brick.RM geopolymer brick normally has more strength(up to 51 MPa)than fired and cementing bricks,and good durability(no efflorescence)with low energy consumption and CO_(2)emissions.Finally,several solutions have been suggested to resolve the issue of the radioactivity of RM brick,and strict regulation of its application has been imposed in some countries,such as China.
