MXPA06007390A - Process for production of glycine enriched sodium chloride crystals with improved flow. - Google Patents

Abstract

The present invention relates to a simple, economical, and efficient cyclic process for producing rhombic dodecahedron shaped glycine enriched, free flowing common salt from brine, said process comprising steps of adding glycine of concentration ranging between 10 to 25% to the saturated brine, evaporating the saturated brine containing glycine to obtain crystals having high content of glycine, with mother liquor, washing the crystals with saturated brine to obtain rhombic dodecahedron shaped glycine enriched common salt having glycine content ranging between 0.5 to 1.0% and a washed brine, combining the mother liquor and the washed brine to obtain resulting brine, subjecting the resultant brine to solar evaporation, and repeating the steps of (iii) to (v) to obtain rhombic dodecahedron shaped glycine enriched common salt from brine with glycine concentration ranging between 0.5 to 1.0%.

Description

PROCEDURE FOR THE PRODUCTION OF SODIUM CHLORIDE CRYSTALS ENRICHED WITH GLYCINE WITH IMPROVED FLOW TECHNICAL FIELD The present invention describes a simple, economical and efficient cyclic process for the production of free flowing common salt, enriched with glycine in the form of rhombic dodecahedron from brine.

BACKGROUND OF THE INVENTION The interest in crystallization, and in various ways of altering the shapes and structures of crystals, has a long history due to an extraordinary scale of physical and chemical properties of materials in crystalline solid state that are ordered by their crystalline form and size . Efforts to modify the crystallization processes in a manner that generates new crystalline forms of substances continue to be of considerable importance for several reasons including, for example, the improvement of the mass handling characteristics of particulate materials, the production of materials that They are stronger or more durable than existing materials, the production of materials that have improved physical characteristics such as optical clarity, the production of materials with a long storage period, the production of crystalline substance with better flow characteristics, etc. Conventional ways of altering the shape (ie the "dominant form") or the crystal lattice (ie, the "morphology") of a crystalline material include: (1) using additives (Weissbuch et al., Science 253: 637, 1991, Addadi et al., Topics in Stereochem, 16: 1, 1996, Addadi et al., Angew, Chem. Int. Ed, Engl. 24: 466, 1985, and Addadi et al., Nature 296: 21. 1982); (2) changing the crystallization solvent (which includes the crystallization of the gas phase) used to dissolve the crystallization solute; (3) change the supersaturation of the crystallization solution; (4) and alter the evaporation rate. Common salt, apart from being an essential dietary component, is a basic raw material for the manufacture of a wide variety of industrial chemicals ie sodium carbonate (commercial soda), sodium hydroxide (caustic soda) and chlorine. In addition, salt is used in textile, dairy, dyeing, food, fertilizer, paper and pharmaceutical industries. The agglomeration of the water-soluble inorganic salt such as common salt is a common storage problem. Agglomeration is believed to occur in said salt due to the formation of solid inter-crystalline bridges that bind the crystals together. The evaporation of the amount per minute of water on the surface of the crystals causes the formation of intercrystalline bridges and therefore the agglomeration over the period of storage time. Understandably, the agglomeration reduces the free-flowing properties of the common salt that has achieved direct negative influence on its use as a dietary component and increases the storage problem. In addition, from the formation of salt bridges, the shape of the crystalline particles has achieved direct influence on the free-flowing property of the substance. The large inter-crystalline surface area contacts, as they are in cubic form, have a negative influence on free-flowing properties. Obviously, the contact area of the inter-crystalline surface is very reduced in the case of spherical or almost spherical crystallites and with which its free-flowing property is increased. In the prior art (R. Kern, 1953, Compt. Rend., 23b, 830), it is shown that supersaturation has a definite effect on the modification of the dominant form of the crystal of common salt. In a high supersaturation, the crystals of common salt grow as crystals in the form of an octahedron (faces (111)) instead of their normal cubic shape (faces (100)). However, these conditions are also extreme to be of any practical use in the production of modified crystals of common salts. In the prior art, urea is known to modify the crystals of common salt from cubic to octahedron since 1783 (J. B. L. Rome de l'lsle, 1783, Crystallographie, 2, Ed. Paris). However, due to its toxicity, urea can not be used as a modifier of the dominant form of common salt for dietary application. In the prior art, (British Patent No. 752, 582, for NV Koninklijke Nederlandsche Zoutindustre, 1954), it is claimed that a small amount of potassium ferrocyanide (4 ppm by weight) inhibits the agglomeration of common salt for an extension considerable. The possible explanation of the efficiency of potassium ferrocyanide as an anti-caking agent is that the modifier of the dominant form causes the inter-crystalline agglomeration bridges to become dendritic and therefore friable. Although it finds application where the common salts have been dispersed over a large area such as in winter defrosting applications, it can not be used as a dietary component due to the possible toxicity of the cyanide compounds. In the prior art (L. Phoenix, British Chemical Engineering, Vol-11, 1966, 34), a long list of various modifiers of the dominant form and its effectiveness as an anti-agglomerating agent has been presented. This list includes cyanide salts of various metal ions, cadmium chloride, lead chloride, potassium silico-tungstate, ammonium triacetamide, victamide, etc. These agents in low concentrations modify the dominant form of the crystals of NaCl of cubic forms (100) to dendrites of (100) and octahedron (111). However, none of these additives can be used in NaCl as a dietary product due to the possible toxicity of the additives and other practical difficulties. In the prior art, (Scrutton, A. New Sci. Group, Imp. Chem. Ind. PLC, Runcorn, UK Symposium Papers - Institution of Chemical Engineers, North Western Branch (1985), (3, Cryst. Habit), 3.1-3.13.), It is shown that NaOH can also act as a modifier of the dominant form of NaCl in an evaporative crystallizer leading to octahedral NaCl crystals (111). Obviously, both the crystallization technique (ie, evaporative crystallization) and the corrosive nature of the modifier of the dominant NaOH form do not offer any potential to develop a method for the generation of modified NaCl crystals for dietary application. In the prior art (Sasaki, Shigeko; Yokota, Masaaki; Kubota, Noriaki. Iwate Univ., Morioka, Japan. Nippon Kaisui Gakkaishi (2001), 55 (5), 340-342), it is described that the octahedral faces (111) of the NaCl crystals appear in the presence of citric acid when they crystallize at an adjusted pH of 2.72. These new faces are never seen in e! Natural pH (= 0.75) of citric acid. Although, citric acid has good health care property, the disadvantage of this method is the requirement of pH adjustment and the fact that only octahedral crystals - which are less spherical in nature compared to the dodecahedral crystals of the present invention - they are obtained. In the prior art (Fenimore, Charles P .; Thrailkill, Arthur, J. Am. Chem. Soc. 1949, 71, 2714), it is described that glycine, pyridine, betaine, and β-alanine in aqueous NaCl solutions modify the dominant form of the NaCl growth crystal; the first causes the formation of rhombic dodecahedrons, the others provide octahedra. The main disadvantage of the prior art is that, even though rhombic dodecahedrons are obtained with glycine, the initial concentration of glycine required is as high as 10% in saturated brine. Furthermore, in the course of the crystallization process, the concentration of glycine continues to increase and can co-precipitate a considerable amount of glycine in parallel with the salt after the glycine saturation limit is reached. This could make the procedure non-economic and obtain unacceptable salt. The previous technique points out its weaknesses and does not establish any solution. Theoretical considerations (A. Julg and B. Deprick, J. Cryst, Growth, 1993, 62, 587, B. Deprick-Cote, J. Langlet, J. Caillet, J. Berges, E. Kassab and R. Constanciel , Theor, Chim. Acta., 1992, 82, 435) suggest that the glycine amphoteric ionic form remains adsorbed in planes (110) of NaCl and thereby make this face grow more slowly compared with the planes (100) resulting in the formation of rhombic dodecahedron crystals. Glycine is more attractive as a modifier of the dominant form since it helps to develop the faces (110) resulting in crystals of NaCl in the form of rhombic dodecahedron (ie, almost spherical). According to Ullmann's Encyplopedia (2002), glycine appears to have a sweet, refreshing flavor, and originates abundantly in mussels and shrimp. This is considered to be an important flavor component in these products. When used as an additive for vinegar, marinades, and mayonnaise, it attenuates the acidic flavor and provides a sweetness characteristic to its aroma. In another prior art [Pillsbury Comp., US 3510310, 1970 and C. Colbum, Am. Soft Drink J. 126 (1971)] glycine is mentioned to be used to cover the remaining flavor of the saccharin sweetener. Glycine has also been shown to exhibit a special condom effect [A. G. Castellani, Appl. Microbiol. 1 (1953) 195. Nisshin Flour Milling, JP 7319945, 1973 (G. Ogawa, K. Taguchi); Chem. Abstr. 81 (1974) 76689 z. Nippon Kayaku, JP-kokai 81109580, 1981; Chem. Abstr, 95 (1981) 202313 b]. The prior art clearly not only indicates that glycine is not harmful in any way, but that it can impart a beneficial effect to certain foods. In the present invention all foods could be those where the salt is used and which contain 0.5-1.0% glycine as an additive.

OBJECTIVES OF THE PRESENT INVENTION The main objective of the present invention is to develop a simple, economical and efficient cyclic process for the production of free flowing common salt, enriched with glycine in the form of rhombic dodecahedron from brine. Still another objective of the present invention is to develop a process wherein the brine can be taken from all possible sources. Still another object of the present invention is to develop a process wherein the drying is at room temperature to make the cost effective. Still another object of the invention is to develop a process wherein the co-crystallized glycine can be largely removed from the salt by washing with saturated brine.

Still another objective of the present invention is to overcome the difficulty in the use of glycine as modifier of the dominant form of the crystal of the salt as described in the prior art and to provide a practical method for generating almost spherical crystallites (rhombic dodecahedrons) of NaCI using glycine as a modifier of the dominant form. Another objective is to show that glycine can be dissolved to the required amount in both artificial and natural brine to effect the modification of the desired dominant form during the production of solar salt. Another objective is to show that the modification of the dominant form of the crystal is better effected when the temperature of the brine during evaporation is less than 40 ° C making it ideally suited for the production of solar salt. Still another objective is to plan simple means for the removal of the excess amounts of glycine that crystallize simultaneously with the salt during the evaporation process. Another objective is to show that the property of modifying the dominant form of glycine is retained in real brine systems containing other dissolved salts. Another objective is to use saturated brine for the washing of the modified salt crystals of the dominant form in order to dissolve the glycine in the saturated brine without loss of salt. Another objective is to adjust the amount of saturated brine taken for washing the modified salt of the dominant form as described in line 23 page 6 above in a way that saturated brine can be obtained with the required concentration of glycine for re-use direct. Another objective is to show that during the washing of the modified salt of the dominant form with saturated brine as described in line 23 page 6 above there is no alteration in the crystal morphology of the salt. Another objective is to show that the salt obtained has superior flow characteristics when compared to the salt produced under similar conditions without the use of glycine. Still another objective is to provide between 0.5-1.0% glycine in the modified salt of the dominant form for purposes where the glycine is presented to have a beneficial effect as micronutrient, flavoring or preservative. Another objective is to produce the modified salt of the dominant form from the saturated brine containing glycine obtained after washing the modified salt of the dominant form. Another objective is to eliminate the loss of glycine except for the extension as desired to obtain a salt fortified with glycine to make the process practically useful.

BRIEF DESCRIPTION OF THE INVENTION The present invention describes a simple, economical and efficient cyclic process for the production of free flowing common salt, enriched with glycine in the form of rhombic dodecahedron from brine, said process comprising the steps of addition of glycine of concentration varying between 10 to 25% to the saturated brine, evaporate the saturated brine containing glycine to obtain crystals that have high content of glycine, with mother liquor, wash the crystals with saturated brine to obtain common salt enriched with glycine in the form of rhombic dodecahedron that has the content of glycine that varies between 0.5 to 1.0% and a washed brine, which combines the mother liquor and the washed brine to obtain the resulting brine, subject the resulting brine to solar evaporation, and repeat the stages of (iii) to (v) ) to obtain common salt enriched with glycine in the form of rhombic dodecahedron from brine with glycine concentration that goes between 0.5 to 1.0%.

DETAILED DESCRIPTION OF THE INVENTION Accordingly, the present invention describes a simple, economical and efficient cyclic process for the production of free flowing common salt, enriched with glycine in the form of a rhombic dodecahedron from brine, said process comprising the steps of glycine addition of concentration which vary from 10 to 25% to saturated brine, evaporate saturated brine containing glycine to obtain crystals that have high content of glycine, with mother liquor, wash the crystals with saturated brine to obtain free flowing common salt, enriched with glycine in form of rhombic dodecahedron that has a glycine content that varies between 0.5 to 1.0% and a washed brine, combine the mother liquor and the washed brine to obtain the resulting brine, subject the resulting brine to solar evaporation, and repeat the steps of (! ii) a (v) to obtain common salt enriched with glycine in the form of rhombic dodecahedron from brine with conce glycine filtration that varies between 0.5 to 1.0%. In an embodiment of the present invention, wherein a simple, economical and efficient cyclic process for the production of free flowing common salt, enriched with glycine in the form of a rhombic dodecahedron from brine, said process comprises the steps of: • adding glycine of concentration that varies between 10 to 25% to saturated brine. • evaporate the saturated brine containing glycine to obtain crystals that have high content of glycine, with mother liquor, • wash the crystals with saturated brine to obtain free flowing common salt, enriched with glycine in the form of rhombic dodecahedron that has the content of glycine ranging from 0.5 to 1.0% and a washed brine, • combining mother liquor and washed brine to obtain the resulting brine, • subjecting the resulting brine to solar evaporation, and • repeating steps from (iii) to (v) to obtain free flowing common salt, enriched with glycine in the form of a rhombic dodecahedron from brine with a glycine concentration ranging from 0.5 to 1.0%. In yet another embodiment of the present invention, wherein the brine is selected from a group comprising synthetic brines, natural brines that include sea brines, sub-soil and lake. In still another embodiment of the present invention, wherein the evaporation is conducted on the temperature scale of 20-40 ° C and more preferably the solar evaporation under ambient conditions. In yet another embodiment of the present invention, wherein the initial concentration of glycine in the saturated brine is maintained in the range of 22-25% (w / v). In yet another embodiment of the present invention, wherein the co-crystallized glycine can be largely removed from the salt by washing with saturated brine. In yet another embodiment of the present invention, wherein the volume of saturated brine taken for washing is such that the glycine content of the brine becomes 22-25% after washing. In yet another embodiment of the present invention, where the washes can be directly subjected to solar evaporation once again salt is produced modified or combined with the remaining mother liquor after the preparation of the salt and then it is subjected to solar evaporation. In yet another embodiment of the present invention, wherein the washing of the salt with saturated brine has no harmful effect on the morphology of the modified salt of the dominant form. In yet another embodiment of the present invention, wherein the modified salt of the dominant form has improved flow characteristics due to its almost spherical shape. In yet another embodiment of the present invention, wherein the modified salt of the dominant form has less tendency to adhere to the plastic surface. In yet another embodiment of the present invention, wherein the efficiency of utilization of glycine is in the range of 95 to 100%. In still another embodiment of the present invention, wherein the glycine in the salt can serve as a flavoring, preservative and micronutrient as presented in the prior art in glycine properties. In yet another embodiment of the present invention, wherein the method A for the production of common salt fortified with glycine and wherein the glycine serves the additional function to be a modifier of the dominant form to produce almost spherical crystals with flow characteristics Improved presents. Glycine is recycled in the method of the invention for practicality. The invention is applicable for the production of salt from both synthetic and natural brines and is especially suitable for the production of solar salt. The present invention describes a method for recycling glycine in the process for the generation of almost spherical crystals of NaCl enriched with glycine micronutrients. The present process is detailed with the recrystallization of commercially available common salt crystals under ambient conditions in the presence of glycine (modifier of the dominant form of the crystal) to produce rhombic dodecahedron crystals with superior free-flowing properties instead of the cubic form normal. The modifier of the dominant form of glycine is continuously recycled while retaining 0.5-1.0% (w / w) of glycine in the salt to serve as a micronutrient. The process can be applied to pure brine solutions or is still treatable for natural brine systems such as sea brine and sub-surface brine. The present invention seeks to make obvious the apparent difficulties in the use of the characteristics of modification of the dominant form of the glycine crystal, that is, the requirement of high concentrations of glycine for the modification of the effective dominant form and the problem of high amounts of glycine in the crystallized salt that is not presented in the prior art but becomes apparent in the course of the present invention. The process as presented in the prior art is practically not feasible both in terms of high glycine use level and also in terms of a also high glycine level in the modified salt of the dominant form which can affect the taste and adaptability of the glycine. the salt. The main inventive steps of the present invention are: the understanding that substantial amounts of glycine are lost in the salt during the evaporation process, (ii) the understanding that the glycine can be washed out of the modified salt of the dominant form using saturated brine without any loss of salt and retaining the desired morphology of the salt crystal, (iii) the additional understanding that the brine obtained after washing the salt contains glycine in the desired amount and can therefore be evaporated with the sun to directly obtain the modified salt of the dominant form without the need for any additional glycine. An additional inventive step is the generation of double benefits of the use of glycine as an additive in the brine, that is to say the property of modification of the dominant form of the crystal that imparts the characteristics of free flow due to the almost spherical shape of the salt and its potential use as a flavoring, preservative and micronutrient in salt. In one embodiment of the present invention the brine used for the production of the modified salt of the dominant form can be either synthetic brine obtained by dissolving the salt or brine of natural origin such as sea brine, sub-soil and lake. In another embodiment of the present invention, glycine is added in saturated brine at a concentration of 22-25% (w / v) to ensure the dodecahedron form of the salt crystals from the onset of crystallization. In another embodiment of the present invention the temperature of the brine is maintained at less than 40 ° C and the evaporation is conducted under ambient. In another embodiment of the present invention the volume of saturated brine is taken on a scale of 100-150 ml and the brine is evated at 10-20% of the original volume. In yet another embodiment of the present invention the mother liquor is decanted and the crystallized salt is washed with fresh saturated brine not containing glycine. In yet another embodiment of the present invention the volume of saturated brine taken for washings is such that the content of glycine in the wash is re-stored at the original 22-25% (w / v), after the addition of the mother liquor of the crystallization of the salt in the wash. In yet another embodiment of the present invention the salt retains its modified form of the dominant form after washing with fresh saturated brine. In yet another embodiment of the present invention the modified salt of the dominant form is clearly more free flowing in nature than the salt produced without glycine during the crystallization process under otherwise identical conditions. In yet another embodiment of the present invention the glycine residue in the salt is in the range of 0.5-1.0% w / w. In yet another embodiment of the present invention the utilization efficiency of glycine is between 95-100%. The following examples are provided by way of illustration and should not be constructed to limit the scope of the invention.

EXAMPLE 1 An excess amount of commercially available NaCl is added to 150 ml of distilled water and the mixture is stirred at room temperature for 0.5 hour. The solid / liquid mixture is then filtered and 100 ml of said saturated brine filtered for crystallization is maintained in an open oven under ambient conditions in the laboratory. After 90% evaporation, the resulting crystals are collected by filtration and dried in a fluidized bed type dryer. Microscopic observation reveals that the crystals are cubic in shape.

EXAMPLE 2 Saturated brine is prepared as in Example 1 above. 10 g of commercially available glycine are added in 100 ml of brine and stirred at room temperature. The resulting solution containing 10% (w / v) of glycine in saturated brine is evaporated under otherwise identical condition as in Example 1 above and the crystals are isolated by filtration and dried in a fluidized bed type dryer. The crystals obtained are largely cubic and octahedral.

EXAMPLE 3 The experiment of Example 2 is repeated with the initial glycine concentration of 15% instead of 10%. NaCl crystals are mainly octahedral in shape. Some glycine crystals are also observed. EXAMPLE 4 The experiment of Example 2 is repeated with the initial glycine concentration of 25% instead of 10%. The crystals of NaCl are mainly in the form of a rhombic dodecahedron. A significant amount of glycine crystals is also found to be co-crystallized with NaCl. The flow properties of the salt crystals are compared qualitatively with those of the salt of Example 1 above and the former are found to be more clearly free-flowing. Salt also has much less tendency to adhere to the surface of the plastic container in which it is stored.

EXAMPLE 5 The experiment of Example 4 is repeated except that the evaporation is carried out at 50 ° C instead of under ambient conditions. The resulting salt crystals are found to be cubic in shape and similarly as described in Example 1. The glycine crystals are also present in the salt.

EXAMPLE 6 The crystals obtained in Example 4 are washed with 90 ml of brine prepared in the above example 1. After washing, the resulting crystals are isolated and dried as described in example 1. The observation of said crystals reveals that the crystals of the salt retain the morphology of rhombic dodecahedron but many of the glycine crystals have disappeared. The IR analysis of the salt using a quantitative calibration technique indicates that the glycine content is 0.83% (w / w).

EXAMPLE 7 The mother liquor obtained from Example 4 is combined with the washes of Example 6 and left for evaporation under ambient conditions. Then the crystals are collected and dried. It is found that the salt crystals are rhombic dodecahedrons in the form and contain significant amounts of glycine crystals in a manner identical to the salt described in example 4. This procedure of recycling the mother liquor and washings is repeated seven times and each time it is found that the salt crystals are rhombic dodecahedrons in the form, with glycine contents of 0.5-1.0.

EXAMPLE 8 The experiment of Example 4 is repeated with 500 ml of sub-surface brine instead of pure brine. The specific gravity of the brine is 1,208 kg / ml. The brine is evaporated to a specific gravity of 1,239 kg / l. The resulting crystals of salt are in the form of a rhombic dodecahedron with significant amounts of co-crystallized glycine crystals. The salt is washed with fresh subsoil brine of 1,208 kg / l and it is found that the morphology of the crystal is retained while it is found that the glycine crystals have largely disappeared. The main advantages of the present invention they are: 1. A process for the generation of salt enriched with glycine with improved flow characteristics due to the almost spherical nature of the crystals. 2.- The use of a permissible additive as a modifier of the dominant form of the crystal. 3.- Versatility of the process as impurities in natural brine have no adverse effect on the modification of the dominant shape of the crystal that leads to improved flow characteristics. 4.- That the production of salt can be allowed through solar evaporation. 5.- Almost quantitative glycine recycling for practicality.

Claims (12)

NOVELTY OF THE INVENTION CLAIMS

1. - A simple, economical and efficient cyclic process for the production of free flowing common salt, enriched with glycine in the form of rhombic dodecahedron from brine, said process comprises the steps of: (i) adding glycine of concentration varying between 10 25% to the saturated brine, (ii) evaporate the saturated brine containing glycine to obtain crystals that have high content of glycine, with mother liquor, (iii) wash the crystals with saturated brine to obtain free flowing common salt, enriched with glycine in the form of a rhombic dodecahedron that has a glycine content ranging from 0.5 to 1.0% and a washed brine, (iv) combining the mother liquor and the washed brine to obtain the resulting brine, (v) subjecting the resulting brine to evaporation solar, and (vi) repeating the stages of (iii) to (v) to obtain free flowing common salt, enriched with glycine in the form of rhombic dodecahedron from brine with concentration glycine ion that varies between 0.5 to 1.0%.

2. The process according to claim 1, further characterized in that the brine is selected from a group comprising synthetic brines, natural brines that include sea brine, sub-soil and lake.

3. The process according to claim 1, further characterized in that the evaporation is conducted on the temperature scale of 20-40 ° C and more preferably the solar evaporation under ambient conditions.

4. The process according to claim 1, further characterized in that the initial concentration of glycine in saturated brine is maintained in the range of 22-25% (w / v).

5. The process according to claim 1, further characterized in that the co-crystallized glycine can be largely removed from the salt by washing with saturated brine.

6. The process according to claim 1, further characterized in that the volume of saturated brine taken for washing is such that the glycine content of the brine becomes 22-25% after washing.

7. The process according to claim 1, further characterized in that the washes can be subjected to solar evaporation to once again produce the modified salt of the dominant form or combined with the remaining mother liquor after the preparation of the salt and then subject to solar evaporation.

8. The process according to claim 1, further characterized in that the washing of the salt with saturated brine has no harmful effect on the morphology of the modified salt of the dominant form.

9. The process according to claim 1, further characterized in that the modified salt of the dominant form has improved flow characteristics due to its almost spherical shape.

10. The process according to claim 1, further characterized in that the modified salt of the dominant form has less tendency to adhere to the plastic surface.

11. The method according to claim 1, further characterized in that glycine utilization efficiency is in the range of 95 to 100%.

12. The process according to claim 1, further characterized in that the glycine in the salt can serve as flavoring, preservative and micronutrient as presented in the prior art in glycine properties.