Technology method for co-producing nano calcium carbonate from melamine tail gas

Abstract

The invention discloses a technology method for co-producing nano calcium carbonate from melamine tail gas. The technology method for co-producing the nano calcium carbonate from the melamine tail gascontains the following steps: (1) introducing melamine tail gas into an inorganic acid for neutralization after the melamine tail gas is subjected to filtering and washing, and compressing collectedgas to obtain carbon dioxide; (2) adding a crystal form control agent into calcium hydroxide suspension liquid, and then introducing the carbon dioxide for a carbonation reaction to generate nano calcium carbonate slurry; (3) at 60-90 DEG C, adding modifying liquid into the nano calcium carbonate slurry in the step (2), and conducting stirring and mixing to obtain modified nano calcium carbonate slurry, wherein the adding amount of a dry basis of the modifying liquid is 2-10% of the mass of the nano calcium carbonate; and (4) conducting filtering, drying and crushing on the modified nano calcium carbonate slurry to obtain the nano calcium carbonate. According to the technology method for co-producing the nano calcium carbonate from the melamine tail gas, the generated nano calcium carbonate is in a shape of a chain, the average primary particle diameter is 40-80 nm, the nano calcium carbonate shows hydrophobicity, an activation grade reaches 99% or above, and the dispersion performancewhen the generated nano calcium carbonate is compatible with a polymer organic matrix is good, so that the application performance of the mechanical performance, the optical performance, the thixotropic performance and the like are significantly improved.

Description

technical field [0001] The invention belongs to the technical field of preparation of nanometer calcium carbonate. Background technique [0002] In industry, 1 ton of melamine is produced, and 1.02 tons of ammonia and 1.13 tons of carbon dioxide are discharged, which is also called melamine tail gas. The recovery and comprehensive utilization of tail gas is the bottleneck of melamine production, which affects the overall benefit of melamine enterprises. At present, the recovery process of melamine tail gas mainly includes co-production of soda ash ammonium chloride method, co-production of ammonium bicarbonate method, co-production of ammonium nitrate method, ammonia carbon separation method and so on. The co-production of soda ash ammonium chloride adopts the process of primary carbonization, secondary ammonia absorption, primary salt addition, and ice machine refrigeration. This process technology is mature, but the added value of the product is low, and the ammonium chlo...

AI Technical Summary

Problems solved by technology

The method of co-production of ammonium nitrate is to absorb tail gas with nitric acid and fix ammonia in ammonium nitrate, but the unreacted carbon dioxide gas in the absorption process is emptied, which causes waste of resources and affects the environment

The carbon and ammonia separation process adopts the absorption-desorption method to realize the separation of ammonia and carbon dioxide, but there is a problem of high heat energy consumption