# US 8,770,500 B2 · Free flowing 100-500 micrometer size spherical crystals of common salt and process for preparation thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,500 B2 - Document ID: US8770500B2 - Status: Granted - Kind: B2 - Application number: 13/689,468 - Filed: 2012-11-29 - Published: 2013-04-11 - Granted: 2014-07-08 - Earliest claimed: 2008-01-07 - Assignees: Council of Scientific and Industrial Research - Applicants: Council of Scientific & Industrial Research - Inventors: Indrajit Mukhopadhyay; Pushpito Kumar Ghosh; Vadakke Puthoor Mohandas - Web page: https://patentgrep.com/patent/US8770500B2 ## CPC - B02C 23/40: with more than one means for adding fluid to the material being crushed or disintegrated - A23L 27/40: Table salts; Dietetic salt substitutes - C01D 3/22: Preparation in the form of granules, pieces, or other shaped products - C30B 7/02: by evaporation of the solvent - C30B 29/12: Halides - C30B 29/60: characterised by shape - Y10T 428/2982: Particulate matter [e.g., sphere, flake, etc.] - B02C: CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN ({household tools and machines for pulverising foodstuffs, e.g. coffee and spice mills A47J42/00; pharmaceutical mortars A61J3/02; mechanical processing of refuse and garbage B03B9/06; dressing mould materials by grinding B22C5/04}; obtaining metallic powder by crushing, grinding or milling B22F9/04; {recovery of plastics by disintegrating B29B17/00; crushing raw materials in starch making C08B30/02; beaters for papermaking D21D1/02; crushing devices specially for transport in mines E21F13/002; slag crushing devices F23J1/00; fuel milling devices in combustion apparatus F23K1/00; household devices for crushing coal F24B15/02; ice disintegrating devices F25C5/02}) - A23L: FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF (preservation thereof A23B) - C01D: COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts of peroxyacids C01B15/00; sulfides C01B17/22; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds other than ammonia and cyanogen, containing nitrogen and other non-metals C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; phosphides C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; cyanides C01C3/08; salts of cyanic acid C01C3/14; salts of cyanamide C01C3/16; thiocyanates C01C3/20) - C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The present invention provides spherical shaped crystals of common salt having size distribution in the range of 100-500 μm and a process for preparation of the said salt. The above mentioned size range is relevant for many important edible and non-edible applications of salt. The salt is demonstrated to have superior flow properties compared to the cubic counterpart. The free flow property of the salt can be further enhanced through surface treatment with additive such as glycine. The salt is produced by cost-effective mechanical means and such production is amenable to scale up. ## Claims ### Claim 1 A process of preparing free flowing spherical shaped crystals of common salt without using any habit modifier, comprising: (a) charging saturated brine optionally along with an anti-solvent into a thermally insulated stainless steel vessel fitted with heating tape on the external wall of the vessel and with a mechanical stirrer of appropriate dimension and configurations with a stirring rate ranging between 200-275 r.p.m; (b) raising the temperature of the brine as obtained from step (a) gradually while stirring up to the pre-set point in the range of 40° C. - 80° C., (c) holding the temperature of the brine as obtained from step (b) at temperature of 58±2° C. and allowing the brine to evaporate under mechanical stirring at speed of 220±10r.p.m; (d) discharging the salt slurry as obtained from step (c) from the bottom when the pre-set point of evaporation is being reached and the brine volume being reduced to 25-35% (v/v) of the initial volume taken; (e) charging the slurry as obtained from step (d) into a centrifuge followed by washing the charged slurry with a spray of saturated solution of sodium chloride; (f) charging the wet salt as obtained from step (e) in a shallow stainless steel tray, followed by drying in the open sun to reduce the moisture content up to 0.5% (w/w) while minimizing agglomeration; (g) sieving the dry salt as obtained from step (f) through progressively finer sieves ranging between 35-60 mesh size to fractionate the salt crystals so as to attain the desired size distribution; and (h) recycling the residual glycine solution in the subsequent batches after topping up with additional glycine if required. ### Claim 2 (depends on 1) The process of claim 1, wherein the brine used is selected from the group comprising synthetic brine or natural brines from sea, sub-soil, lake and plant sources. ### Claim 3 (depends on 1) The process of claim 1, wherein the anti-solvent used is selected from the group consisting of methanol, ethanol and propanol in a concentration range of between 0.3-0.5% (v/v). ### Claim 4 (depends on 1) The process of claim 1, wherein the stainless steel vessel used is having a cylindrical geometry with internal diameter of 0.1-1.0 m, height of 0.5-1.0 m for a volume capacity of 100L. ### Claim 5 (depends on 1) The process of claim 1, wherein the bottom of the stirrer is placed at a depth of 0.10 m - 0.2 m within a stainless steel vessel having a cylindrical geometry with internal diameter of 0.1-1.0 m, height of 0.5-1.0 m for a volume capacity of 100 L. ### Claim 6 (depends on 1) The process of claim 1, wherein the mechanical stirrer used is having propeller type of blade having an inclination angle of 10° -20° and blade diameter being in the range of 0.1-0.5 m. ### Claim 7 (depends on 1) The process of claim 1, wherein the stirring rate is maintained in the range of 245-255 r.p.m. and is a critical parameter to obtain the desired morphology of the crystals. ### Claim 8 (depends on 1) The process of claim 1, wherein the effective stirring requires a minimum initial free volume in the range of 20-40% to be maintained to ensure proper stirring of the entire volume of brine. ### Claim 9 (depends on 1) The process of claim 1, wherein the centrifuged product is alternatively dried in a fluidized bed drier or in a forced air oven at 35±5° C. without significant caking. ### Claim 10 (depends on 1) The process of claim 1, wherein the sieving has been performed using 35 mesh size sieves for separating the crystals larger than 500 μm and 45-60 mesh size sieves for separating fine salt crystals. ### Claim 11 (depends on 1) The process of claim 1, wherein the product obtained from the process is packaged in air tight plastic bags for storing for at least up to 3 months.