Process for the preparation of a spray powder comprising one or more glycine-n,n-diacetic acid derivatives and use of the spray powder for producing compression agglomerates

A process for the preparation of a spray-dried powder comprising at least one glycine-N,N-diacetic acid compound of formula (I)

• MOOC—CHR—N(CH2COOM)2 (I),
• wherein R is a C1-12-alkyl and M is an alkali metal, the process comprising:
• preparing an aqueous solution comprising the at least one glycine-N,N-diacetic acid compound;
• concurrently passing the aqueous solution and air into a spray-drying apparatus;
• atomizing the aqueous solution in the spray-drying apparatus, to obtain fine liquid droplets;
• and
• drying the fine liquid droplets, to obtain the spray-dried powder,
• wherein a temperature gradient between the aqueous solution and the air is in a range from 70 to 350° C.,
• wherein the atomization comprises feeding the aqueous solution onto at least one disk which rotates at a peripheral speed of ≧100 m/s, or compressing the aqueous solution with a pump to a pressure of ≧20 bar absolute and feeding the aqueous solution into the spray-drying apparatus via at least one jet, and
• wherein a content of the at least one glycine-N,N-diacetic acid compound in the aqueous solution passed into the spray-drying apparatus is ≧84% by weight, based on a total weight of the dry mass.