Method for producing pure melamine
AssigneeAmi Agrolinz Melamine International GmbH
InventorWolfgang Ruech
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Abstract
The invention relates to a method for producing pure melamine by preparing a melamine melt, which is obtained in a high pressure process and from which the reaction gases are removed. Said method is characterized in that the melamine melt is quenched by water with a purity in excess of 95 wt. %, that NH3 and CO2 are subsequently removed from the obtained melamine solution and that alkali is added to said melamine solution and the mixture is then left to rest, whereby pure melamine is obtained by crystallization. Thus a melamine can be obtained with the same quality as that produced in known comparative methods, using smaller quantities of alkali.
Claims19
A process for the preparation of pure melamine by working up a melamine melt obtained from a high pressure process and freed from the reaction off gases, comprising the steps of:
- a) quenching the melamine melt with water having a purity of more than 95% by weight, whereby the quenching is effected at from 170 to 220° C.,
- b) removing NH3 and CO2 from the melamine solution obtained in step a), and
- c) adding alkali to the melamine solution and allowing said solution to reside,
- d) whereupon pure melamine is obtained by crystallization.
Dependencies are inferred from the claim text.