Press-granulating process of non-ductile salts

Abstract

Process of press-granulating non-ductile salts and salt mixtures, such as kieserite (MgSO 4 .H 2 O), langbeinite (K 2 SO 4 .2 MgSO 4 ), polyhalide (K 2 SO 4 .MgSO 4 2 CaSO 4 .2 H 2 O), arcanite (K 2 SO 4 ) and anhydrite (CaSO 4 ) for preparing stable, storable granulate, by pressing a mixture of fine grains of salt and a viscous, sugar-containing additive, such as molasses having a total sugar content in the dry matter of from 47 to 55%, by roller pressing at pressures up to 260 bar. The press scraps initially obtained, which are ductile, are solidified by maturing of the material at temperatures between 20 and 40° C. and maturing times of 3 to 8 hours prior to crushing them in impact mills and sieving.

What is claimed is: 
     
         1 . Product obtainable according to a process for press-granulating of non-ductile salts and salt mixtures, such as kieserite, langbeinite, polyhalide, anhydride and arcanite, by roller pressing at pressures of up to 280 bar, characterized in that a viscous additive in form of sugar-containing by-products of the sugar cane or sugar beet process is added in an amount of 1.5 to 8% by mass to a powder-like salt or salt mixture to be granulated in one or a plural of mixers in series, and compacting the homogenized mixture in a press granulating process using roller presses. 
     
     
         2 . Product obtainable according to a process for press-granulating of non-ductile salts and salt mixtures, such as kieserite, langbeinite, polyhalide, anhydride and arcanite according to  claim 1  using roller pressing at pressures up to 280 bar, manufacturing of press scraps (foil), crushing of the foil using impact mills, sieving of the granulated grain of crushed material using a double deck sieve and re-feeding of the undersized and oversized grain into the press cycle, characterized in that from 1.5 to 8% by mass of a viscous additive in form of sugar-containing by-products of the sugar cane or sugar beet process are added to a powder-like salt or salt mixture to be granulated in one or a plural of mixtures in series, followed by compacting the homogenized mixture in a press granulating process using roller presses. 
     
     
         3 . Product according to  claim 2 , characterized in that as the additive, preferably 2 to 5 mass % molasses with 47 to 55 mass % total sugar in the dry matter is added, followed by pressing the homogenized mixture to soft scraps, pre-crushing said pressed scraps and, after a maturing time of 3 to 8 hours, crushing them in impact mills and sieving. 
     
     
         4 . Product according to  claim 3 , characterized in that the maturing of the material obtained in the press process and the following pre-crushing is carried out in silos or open storage. 
     
     
         5 . Product according to  claim 4 , characterized in that the finely grained material and the chunky material after the press process and following pre-crushing are separated, and the chunky material is cured by maturing, followed by crushing the cured oversized material in impact mills. 
     
     
         6 . Product according to  claim 5  characterized in that the temperature of the mixing process, pressing and maturing is preferably 20 to 40° C. 
     
     
         7 . Product according to  claim 1 , comprising at least one non-ductile salt or salt mixture, such as kieserite, langbeinite, polyhalide, anhydride and arcanite, and sugar containing by-products of the sugar cane or sugar beet process.