A method for heterogeneous catalytic hydrolysis of melamine, cyanuric acid or melamine oat waste residue

Abstract

The invention relates to a heterogeneous catalytic hydrolysis method of melamine, cyanuric acid and melamine OAT waste residue. The method is characterized by taking activated aluminum oxide or pseudo-boehmite as a catalyst, hydrolyzing in a sealed pressure container under the intrinsic pressure at the temperature of 190-240 DEG C, and decomposing melamine, cyanuric acid and melamine OAT waste residue into ammonia and carbon dioxide, wherein the melamine OAT waste residue mainly comprises melamine, cyanurodiamide, ammelide and cyanuric acid; meanwhile, ammonia and carbon dioxide generated by hydrolysis are used as raw material gases for producing urea and can be combined with an urea device; the method provides an effective resource recycling method and is applied to industrial enterprises for producing melamine at present.

Description

technical field [0001] The invention relates to a method for heterogeneous catalytic hydrolysis of melamine, cyanuric acid or melamine OAT waste residue, which belongs to the technical field of solid waste treatment and circular economy. Background technique [0002] As an important chemical intermediate, melamine is widely used in synthetic plastics, water-soluble coatings, adhesives, fibers and flame retardants. In 2015, the global demand for melamine was about 2 million tons, and it continued to grow every year. In the process of producing melamine by high-pressure method, melamine OAT waste residue will be produced, and the output is quite huge. If these waste residues cannot be disposed of reasonably, it will inevitably have a certain impact on the environment and reduce the utilization rate of chemical resources. The main components of melamine OAT waste residue are melamine, ammeline, ammeline, and cyanuric acid. They are all nitrogen-containing compounds containing ...

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Problems solved by technology

A kind of method is to separate various components in the OAT and utilize, as separating melamine [WO:0136397A1] in the OAT by adjusting the pH value, but consume a large amount of acid and alkali in the technique, and only reclaim wherein melamine; According to each group Sublimatographic separation of melamine,ammerine,ammeride and cyanuric acid[J].Japan analyst,1978,27:321-325.]

Another method is to use melamine OAT waste residue to prepare other products, such as the preparation of sulfonated amino resins, or the preparation of cyanuric acid, but due to the complexity of OAT components, the prepared products have low active ingredients and complicated processes [Lahalih SM, Absihalabi M. Recovery of solids from melamine waste effluents and their conversion to useful products[J].Ind EngChem Res.1989,28(4):500-504;EP:0124710,1984;US:4963674.1990;Ren Baozeng, Luo Tingliang, Li Chen, etc. .Prepare cyanuric acid from solid waste discharged from melamine production[J].Environmental Engineering,2003,21(4):4-44]

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