Method for preparing nano silicon dioxide by using waste concrete sand powder

Abstract

The invention relates to a method for preparing nano silicon dioxide by using waste concrete sand powder, which comprises the following two carbonization processes: 1, enabling the waste concrete sand powder to react with industrial tail gas rich in carbon dioxide in a solution, then adding soluble alkali, and fully stirring and reacting; and 2, reacting the solution obtained in the step 1 with industrial tail gas rich in carbon dioxide again, precipitating, separating and pickling to obtain the nano silicon dioxide with the purity of more than 95% and the particle size of 1-100 nanometers. In addition, the invention also provides silicon dioxide and calcium carbonate-rich materials prepared by the method of the invention, and products prepared from the silicon dioxide and calcium carbonate-rich materials. 本发明涉及一种利用废弃混凝土砂粉制备纳米二氧化硅的方法，该方法包括两步碳化过程：第一步使废弃混凝土砂粉与富含二氧化碳的工业尾气在溶液中反应，然后加入可溶性碱充分搅拌并反应；第二步使第一步反应获得的溶液与富含二氧化碳的工业尾气再次反应，经沉淀、分离、酸洗得到纯度大于95％、粒度介于1‑100纳米的纳米二氧化硅。另外，本发明还提供了由本发明的方法制备的二氧化硅、富碳酸钙材料以及由其制备的制品。