Lime-free and low-density autoclaved aerated concrete block and preparation method thereof

The invention relates to a lime-free and low-density autoclaved aerated concrete block. The block is prepared from dry materials and auxiliary materials, wherein the dry materials comprise components in percentage by weight as follows: 40%-70% of Yellow River sand, 20%-40% of Portland cement, 1%-7% of special cement, 1%-10% of FGD (flue gas desulfurization) gypsum and the balance of waste materials, and the waste materials are leftovers produced by cutting in the production process of the autoclaved aerated concrete block; the auxiliary materials comprise hydrogen peroxide, potassium permanganate, a foam stabilizer, a water reducer and polypropylene fibers, the hydrogen peroxide accounts for 0.40%-1.0% of the weight of the dry materials in terms of H2O2, the potassium permanganate accounts for 0.015%-0.02% of the weight of the dry materials, the foam stabilizer accounts for 0.02%-0.04% of the weight of the dry materials, and the water reducer accounts for 0.05%-0.15% of the weight of the dry materials. According to the product, the cheap Yellow River sand is adopted, lime is not consumed, the relatively cheap hydrogen peroxide is taken as a foaming agent, and performance of the product can meet the national standard requirement.