Ca(OH)(2)-Al(OH)(3) and CaCO3-Al(OH)(3) mixtures with Ca/(Ca + Al) ratios in the range 0 to 1 were calcined in the temperature range 873-1673 K for studying the effect of the calcination temperature and Ca/(Ca + Al) ratio on the calcination products. XRD analysis showed that the mixtures with Ca/(Ca + Al) ratios in the range 0.68-0.83 and calcined around 1273 K gave lime (CaO) as the major product and mayenite (Ca12Al14O33), Ca9Al6O18, and Ca5Al6O14 as the minor products. These calcination products indicated that the efficiencies of the removal of chromate and borate from the solution were high. Upon immersing these calcination products in chromate and borate solutions, Ca4Al2CrO10 center dot 12H(2)O and Ca4Al2(HBO3)(0.5)(OH)(13)center dot 6H(2)O were formed, respectively; the Ca/(Ca + Al) molar ratio in these compounds was 0.68, which was close to that in the raw mixtures. A Ca/(Ca + Al) ratio in the range 0.68-0.83 resulted in the optimum removal of chromate and borate from the solution. The Ca/(Ca + Al) ratio was more effective than these crystalline components in these calcination products. Further, Ca(B(OH)(4))(2)center dot 2H(2)O precipitated as a result of borate removal.