Method for manufacturing nano calcium carbonate from high-concentration carbon dioxide industrial exhaust gases

Abstract

The invention provides a method for manufacturing a nano-grade calcium carbonate from high-concentration carbon dioxide industrial exhaust gases, which comprises the following steps: (1) adding a crystal nucleus forming accelerator into a suspension of a calcium hydroxide; (2), introducing a gas containing 50 to 100 volume percent of a carbon dioxide, adding a dispersant when a carbonization rate is over 80 percent, and continuously introducing the gas for 10 to 20min when the pH value of the suspension is reduced to between 6.5 and 7.0, wherein the final temperature of a reaction slurry liquid is 45 to 70 DEG C; and (3) adding the aqueous solution of a cladding agent into the suspension of the calcium hydroxide, wherein a cladding and activating time is 1 to 2h, and then collecting the nano-grade activated calcium carbonate from the reaction product. The method of the invention greatly reduces the equipment and operation costs, quickens the carbonization reaction, saves the time of the carbonization reaction and energy, reduces the energy consumption, increases the oversaturated concentration of the calcium carbonate, and finally generates narrowly distributed nano-grade calcium carbonate particles the grain size of which is uniform.

Description

technical field [0001] The invention relates to a preparation method of calcium carbonate particles, more specifically, relates to a method for preparing nanometer calcium carbonate particles by using high-concentration carbon dioxide gas discharged from industry. technical background [0002] The commonly used industrial production method of nano-calcium carbonate is bubbling carbonization method. The stirred tank carbonization method is a method widely used at home and abroad to produce nano-calcium carbonate. This method needs to strictly control the carbonization temperature at 10-30°C during the entire carbonization process, while The formation process of calcium carbonate is an exothermic reaction, so a huge forced cooling heat exchange system is required. [0003] Chinese patent application publication CN1330039A discloses a method for synthesizing calcium carbonate by mechanical stirring and mixing at a relatively low temperature, then heating the calcium carbonate s...

AI Technical Summary

Problems solved by technology

During the carbonization reaction of nano-calcium carbonate, what actually happens is that the calcium ions dissolved in the solution and the carbon dioxide dissolved in the liquid film undergo a carbonization reaction to form calcium carbonate. Since the concentration of carbon dioxide in the kiln gas is relatively low, the carbonization reaction time Longer (more than tens of hours are usually required in actual industrial production), and the effective utilization rate of equipment is low

At the same time, due to the low concentration of carbon dioxide in the kiln gas, it is not conducive to the nucleation and growth of calcium carbonate, and the particle size of the produced calcium carbonate is uneven, which affects the performance of calcium carbonate products.

Images