A method for preparing nano-calcium carbonate based on subcritical hydrolysis

Abstract

The invention belongs to the technical field of preparation of nanometer calcium carbonate, and discloses a method for preparing nanometer calcium carbonate based on a subcritical hydrolysis method. The method for preparing nanometer calcium carbonate based on subcritical hydrolysis method comprises the steps that firstly, a shell grinding method is adopted to obtain millimeter calcium carbonate,the supercritical hydrolysis method is adopted for performing hydrolysis to extract amino acids in shells under the high pressure environment, and the step of drying is performed to obtain the nanometer calcium carbonate. The shells are comprehensively utilized, waste materials are recycled, and the problem that environment is contaminated by shells in coastal regions is solved; the shells are mainly prepared from calcium carbonate and protein, contain few impurities and are easily separated (shells are abundant in coastal area of the city of Xiamen in China), the shells as ocean resources inChina can be comprehensively utilized, and promotion is achieved; the shells are convenient to collect at the coastal regions and are cheap and easy to obtain, the raw material cost for preparing thenanometer calcium carbonate can be lowered, and the market competitiveness of the nanometer calcium carbonate product is improved.

Description

technical field [0001] The invention belongs to the technical field of preparation of nano-calcium carbonate, in particular to a method for preparing nano-calcium carbonate based on a subcritical hydrolysis method Background technique [0002] At present, the commonly used prior art in the industry is as follows: my country is the largest shellfish breeding country in the world, and its annual output accounts for more than 60% of the world's total shellfish output. Data show that the annual output of shells in my country reaches 500,000 tons, yet, shells accounting for 1 / 3 of the weight of shellfish are discarded, and only 150,000 to 180,000 tons of discarded shells can be produced in one year. The coast of Fujian is a subtropical ocean and a shallow continental shelf, with many harbors and vast shallow beaches. Shellfish farming has a long history, rapid development, high output and rich varieties. The material composition of shells is divided into two parts: inorganic mat...

AI Technical Summary

Problems solved by technology

[0023] (1) At present, the development of shellfish in my country is mainly to process its edible parts, and a large number of shells are discarded as garbage. The organic matter left in these discarded shells will be corrupt and smelly during the long-term stacking process, which will endanger the lives of residents and the environment. cause serious pollution

[0024] (2) Limestone is used as raw material in the preparation of nano-calcium carbonate by traditional carbonization method, but limestone has many impurities and is not easy to separate, and limestone resources are lacking in some areas

[0025] (3) The traditional carbonization process for preparing nano-calcium carbonate is relatively cumbersome; and the calcination step needs to be powered by other forms of energy, such as burning charcoal or power consumption to maintain the high temperature conditions required for calcination; the traditional carbonization method prepares nano-calcium carbonate. To remove impurity ions, the use of impurity removal reagents will cause a certain loss of the original calcium ions, and due to the presence of water in the system, part of the calcium carbonate will harden, and the removal will also cause loss of calcium ions

The utilization rate of shellfish in Fujian Province's shellfish resources has been at a low level, which not only causes waste of resources but also pollutes the environment

Images