Method for making ecological cement and active sand with waste concrete and sludge

Abstract

A method for producing ecologic cement and active sand by using waste concrete and sludge comprises the following steps: breaking waste concrete, separating to form fine particles with the particle size being smaller than 10mm and coarse particles with the particle size of 10-40mm, processing sludge by adopting a ridge granule seed crystallization technology to form ridge granule seed crystallized sludge, crushing aged and caked sludge to make the particle size be not greater than 40mm, producing ecologic clinker from the coarse particle waste concrete with the particle size of 10-40mm, sludge, a correction material and an alteration agent through a dry rotary kiln production line technology, producing active slag powder and active sand from fine particle waste concrete with the particle size being smaller than 10mm through the dry rotary kiln production line technology, and producing the ecologic cement from the produced ecologic clinker and active slag powder through the dry rotary kiln production line technology. The method fully utilizes most widespread and maximum limestone coarse aggregate waste concrete, sludge and other wastes to produce the ecologic cement and the active sand, so protection of social, ecologic and natural environment is facilitated.

Description

Technical field [0001] The invention relates to a method for preparing ecological cement and activated sand from waste concrete and sludge. Background technique [0002] At present, the average daily output of waste concrete in my country has exceeded one million tons, and it is growing at an annual rate of 8%. It is expected to reach 650-700 million tons in 2020. If these waste concrete cannot be reused well, it will not only damage the ecological environment, but also a huge waste of resources, and will further aggravate the production burden of the building materials industry. my country's cement production ranks first in the world, with a cement production capacity of nearly 2.8 billion tons in 2014; at the same time, the raw materials such as limestone and clay required for cement production are facing a shortage of resources. Using waste concrete to prepare recycled cement, through the closed circulation of cement-concrete materials, on the one hand, it can directly reduce...

AI Technical Summary

Problems solved by technology

Domestically speaking, it is very difficult to dry and incinerate sludge at present, because the flocculated gel state water retention structure of the sludge itself has excellent water retention, and the cost of dehydration and drying is extremely high. The composition is very complex, and the colloidal water retention of sludge is good, dehydration and drying are extremely difficult, and harmful components such as chlor-alkali sulfur are also high or high. Directly replacing part of coal or raw materials with unmodified sludge will not only increase the Coal consumption and electricity consumption also increase the operating cost of the enterprise, and even affect the operation of the kiln during production, and even affect the performance of the cement. Therefore, even if the current government subsidies of about 200 yuan or more for each ton of sludge processed by the local government are still Few cement companies are really willing to deal with sludge

[0012] The practical problem is that although it is known that waste concrete and sludge contain chemical components such as silicon, aluminum, iron, calcium, etc. required for cement clinker production, and are considered to be used as raw materials for cement clinker production, so far, effective use of waste concrete There is still no practical method for the production of cement clinker, and there has not been any practice or theoretical analysis report on the comprehensive utilization of waste concrete and sludge to produce clinker, let alone any specific comprehensive utilization of waste concrete and sludge to produce clinker. method of feeding