Abstract: Systems and methods for treating spent process water containing sulfate and calcium ions. A treatment method includes adding sodium aluminate to a volume of the spent process water to form a solid precipitate containing aluminum, calcium, and sulfate compounds such as ettringite (Ca6Al2(SO4)3(OH)12.26H2O). The solid precipitate is removed from the process water by clarifying and/or filtration, yielding a disposable solid waste material and a treated process water having concentrations of sulfate and calcium ions significantly lower relative to the initial concentrations in the spent process water.

Abstract: Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets and low density fillers distributed throughout. The combination of entrained air pockets and low density fillers provide a low density fiber cement matrix with physical and mechanical properties similar to comparable low density fiber cement matrix without entrained air pockets.

Abstract: Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets distributed throughout. Also disclosed herein are air entrainment systems and methods for manufacturing aerated low density fiber cement panels or sheets with consistent air void content and uniform air void distribution. Also disclosed herein are air entrainment technologies adapted to work in conjunction with the Hatschek process to produce aerated fiber cement articles having controlled air void content and distribution.

Abstract: Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets and low density fillers distributed throughout. The combination of entrained air pockets and low density fillers provide a low density fiber cement matrix with physical and mechanical properties similar to comparable low density fiber cement matrix without entrained air pockets.

Abstract: Disclosed herein are low density fiber cement articles, such as fiber cement building panels and sheets, comprised of multiple overlaying fiber cement substrate layers having small and uniform entrained air pockets distributed throughout. Also disclosed herein are air entrainment systems and methods for manufacturing aerated low density fiber cement panels or sheets with consistent air void content and uniform air void distribution. Also disclosed herein are air entrainment technologies adapted to work in conjunction with the Hatschek process to produce aerated fiber cement articles having controlled air void content and distribution.