Method for preparing high-strength lightweight aggregate by use of building waste residue, casting waste sand and sludge

A method for preparing a high-strength lightweight aggregate by the use of building waste residue, casting waste sand and sludge comprises the following steps of: (1) taking the building waste residue, casting waste sand and sludge as raw materials; (2) drying the raw materials, followed by ball milling, and adding throughs into water with uniformly mixing; (3) extruding the raw materials for molding; (4) sintering: drying a blank material at the temperature of 105 DEG C for 5-6 hours, heating to the temperature of 450 DEG C, keeping warm for at least 10 minutes, heating up to the temperatureof 1125-1150 DEG C to roast for at least 10 minutes, and stopping heating; (5) naturally cooling to room temperature so as to obtain the high-strength lightweight aggregate. The produced high-strength lightweight aggregate in the invention completely meets the high-strength lightweight aggregate standard in Lightweight Aggregate and its Test Method GB/T17431.2-1998. According to the invention, building waste, industrial waste and waste generated from city or industrial sewage are taken as the raw materials to prepare the lightweight aggregate for buildings. By the adoption of the high-strength lightweight aggregate, problems such as the environmental pollution due to the difficulty of processing building waste residue, used sand regenerating dust and sludge are solved. In addition, the high-strength lightweight aggregate, which is prepared by using waste as the raw materials, replaces building materials prepared by natural raw materials to change waste into valuables, and has obvious environmental benefit and economic benefit.