Modified mineral adsorbents were prepared by changing the content of silicon oxide， alumina oxide， and calcium oxide in kaolin. The mass， morphology and phase transformation of the modified mineral absorbents were analyzed at 900-1 450 ℃. The results show that amorphous aluminosilicates are the main component of mineral adsorbents at 900 ℃. At 1 200 ℃， amorphous aluminosilicates transform into mullite and cristobalite. Increasing silicon oxide content inhibits this transformation， while increasing alumina content decomposes into corundum phase and improves the chemical stability of the adsorbent. Calcium oxide reacts with active silicon aluminum to form calcium feldspar. When the temperature exceeds 1 200 ℃， an appropriate increase in silicon oxide content can reduce the melting sintering of mineral adsorbents and reduce the release of Pb. However， increasing alumina oxide and calcium oxide contents eliminate and intensify the melting sintering of mineral adsorbents， and has little effect on the release of Pb. The research can provide guidance for improving the solidification of heavy metals in the collaborative disposal of cement kilns.