CA1142324A - Preparation of useful mgcl.sub.2 solution with subsequent recovery of kc1 from carnallite - Google Patents

Abstract

ABSTRACT
A method of beneficiating a mixed salt mineral ore containing potassium and magnesium values in either the sulfate or the chloride form and either their anhydrous or hydrated form which allows the recovery of anhydrous magnesium chloride and the simultaneous recovery of either commer-cially acceptable potassium chloride or commercially acceptable potassium sulfate. This beneficiation or these mixed salt mineral ores allows the separation and isolation of several critical and economically valuable salts.
These salts are anhydrous magnesium chloride, anhydrous potassium sulfate, and/or anhydrous potassium chloride.

Description

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In the process of manufacturing magnesium nletal, the electrolysis of anhydrous magnesium chloride in a molten salt eutectic is normally practiced.
The magnesium metal is separated from the bath and electrolysis cell by flo-tation in molten baths that contain primarily MgC12, KCl, and NaCl along with additional CaC12 salts. Other eutectic "mixed" salt baths used to recover magnesium metal have included molten baths containing MgC12 - LiCl mixtures with other salts such as KCl, BaC12, NaCl, and CaC12. Various types of trace metal, such as vanadium, may be added to the mixed baths as salts to enhance -their electrolysis characteristics.
One of the more profound difficulties found in operating an elec-trolysis procedure to manufacture magnesium metal is the build up of cell "smut", which is primarily magnesium oxides, in the salt bath. This "smut"
is not soluble in the eutectic molten baths and accumulates on electrodes, in flow paths, and generally throughout the equipment in contact with the molten salt bath. The presence of this "smut" is harmful to the electrolysis cell operation. Its presence is caused primarily by insufEiciently dried magnesium chloride being used as a cell feed during continued electrolysis.
Recentlyl new procedures have been developed to obtain high quality anhydrous magnesium chloride. These processes are described in United States Patent 3,983,22~ and in United States Patent 3,966,888 both issued to ~llain, et al. The patents issued to Allain, et al, describe a process which success-fully manufactures extremely high quality anhydrous MgC12 from MgC12 hydrate salts or concentrated MgC12 aqueous solutions. These starting materials are admixed with ethylene glycol and then exposed to temperatures sufficient to distill from these admixtures all water initially present, thus leaving an anhydrous ethylene glycol solution of MgC12. This anhydro~ls ethylene glycol-MgC12 solution is treated with anhydro-ls ammonia forming the insoluble hexa ammoniate complex o~ formula MgC12 6Nh3 which precipitates, and is then ;,~

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filtered from this glycol - MgCl2 6N~13 slurry. Subsequent unique washing stepsJ solvent recovery steps, and a final roasting process which drives off ammonia ~Eor recycle) and recovers high quality ~gCl2 (anhydrous) completes the process.
One of the difficulties of the economic operation of the above pro-cess is the source of the MgCl2 hydrate salts or concentrated solutions.
Brines, bitterns, and even sea water may be used to recover these hydrated MgCl2 salts or concentrated aqueous solutions. It would be beneficial also to use various types of naturally occurring mineral ores or mixed salts con-taining magnesium values if a process could be found to simply and economical-ly convert these mineral ores and mixed salts to anhydrous MgCl2.
We have discovered that we can easily achieve the beneficiation of certain ores and mixed salts containing magnesium values, and by such bene-ficlation open up many geographic locations to possible economic consideration as sites to manufacture MgCl2 ~anhydrous) and possibly even magnesium metal.
We have particularly discovered a process which converts any common magnesium containing sulfate or chloride salt, double salt, or mixture there-of to anhydrous magnesium chloride o:E exceptionally high purity while simul-taneously recovering either fertilizer grade potassium sulfate or recovering anhydrous and economically valuable potassium chloride. We have also success-fully discovered a combined process which can use the anhydrous potassium chloride recovered from the beneficiation of a carnallite double salt to im-prove the economics of recovering anhydrous magnesium chloride from a mîxed salt containing magnesium sul-fate and potassium sulfate.
We have discovered a method of beneficiating a mixed salt mineral ore containing potassium and magnesium values in either the sulfate or the chloride form and in either their anhydrous or hydrated form which allows the recovery of anhydrous magnesium chloride and the simultaneol1s recovery of either commercially accep-table potassium chloride or commercially acceptable potassium sulfate. This beneficiation of these mixed salt mineral ores allows the separation and isolation of several critical and economica]ly valuable salts. These salts are anhydrous magnesium chloride, anhydrous potassium sulate, and/or anhydrous potassium chloride.
We have simultaneously discovered that we may obtain anhydrous mag-nesium chloride from either mixed chloride ores containing magnesiwn and potassium values, such as carnallite, or independently from mixed salts or magnesium sulfate and potassium sulfate which may also be found in various locations throughout the world. Examples of the mixed sulfate salts contain-ing both magnesium and potassium values are the mineral ores named Langbei-nite, Leonite, Shoenite, and Picromerite. The Langbeinites are often given the formula K2S04 2MgS04. Leonite, on the other hand, is a tetrahydrate having the formula K2S0~ MgS04 4H20. The hexahydrate salt is referred to as shoenite. Picromerite is another mineral name given to a magnesium-potas-sium sulfate ore which is commercially mined.
The potassium-magnesium containing mixed salts which have chloride ion concentrations are normally referred to as carnallites. These materials are most often found containing water of hydration, for example, MgC12 KCl The invention, therefore9 is a combination o~ a method of benefici-ating a mixed salt mineral ore containing potassium chloride and magnesium chloride and/or their hydrates which allows the recovery of anhydrous magne-sium chloride and the simultaneous recovery of commercially acceptable potas-sium chloride, a method of beneficiating a mixed salt mineral ore containing potassium and magnesium sulfate and/or their hydrates which allows the recov-ery of anhydrous magnesium chloride and the simultaneous recovery of commer-cially acceptable potassiwn sulfate, and finally, the combination of these two ~2~

methods of beneficiating magnesium ores of the type mentioned in such a manner that a commercial facility may use either a carnallite ore as a feed material, a mixed potassium/magnesium sulate ore as a feed material, or may use a com-bination of these two mineral ores or types of ores as feed material to the process.
The simplest way of describing our invention is to outline the sep-arate processes involved and then demonstrate their mutual combination.
Toward that end, we initially will describe the process of beneficiating a carnallite type ore primarily containing MgC12 KCl and its various hydrate forms.
The method of beneficiating a mixed salt mineral ore containing potassium chloride and magnesium chloride and/or their hydrates allows the recovery of anhydrous magnesium chloride and the simultaneous recovery of commercially acceptable potassium chloride. This beneficiation of these carnallites allows the separation and isolation of two critical and economic-ally valuable inorganic salts. These two salts are anhydrous magnesium chlo-ride and potassium chloride. This method of beneficiation of these carnallite mineral ores which contain potassium chloride and magnesium chloride comprise the following steps:
(a) Dissolving the carnallite mineral ores in the minimum amount of water required to obtain complete solubility, thereby obtaining a carnallite solu-tion;
(b) Filtering from the carnallite solution of ~a) any residual precipitates which are not soluble in said solution, thereby obtaining a filtered solution;
(c) Adding ethylene glycol to the filtered solution of (b) in sufficient quantities to solubilize all magnesium chloride present in said filtered solu-tion, thereby obtaining an ethylene glycol-water-carnallite solution;
~d) Dehydrating the ethylene glycol-water-carnallite solution of step (c) by 3~

distilling water there-frol~, thereby obtaining an anhydrous solution of mag-nesium chloride in ethylene glycol which may contain up to about 2.0% potas-si~ chloride (by weight) and a precipitate of cmhydrous potassium chloride, said precipitate then being removed and recovered from said solution of mag-nesium chloride in ethylene glycol;
(e) Adding anhydrous ammonia to the anhydrous solution of magnesium chloride in ethylene glycol~ thereby forming a complex precipitate of MgC12 6NH3 which may contain small quantities of KCl, said precipitate being filtered from the solution~ washed with a low molecular weight solvent for ethylene glycol, said solvent having been saturated with anhydrous ammonia prior to washing said precipitate and recovering said washed precipitate of anhydrous MgC12 . 6NH3;
(f) Heating the MgCI2 6NH3 of (e) to temperatures sufficient to drive off all ammonia, thereby recovering anhydrous magnesium chloride.
It is noted in step te~ that it is possible to remove trace quanti-ties of potassium chloride from the MgC12 6NH3/glycol cake by washing it with a low molecular weight solvent, for example methanol, saturated with ammonia in quantities sufficient to remove the potassium chloride. This is a surprising discovery since one would expect that the ammonia saturated solvent would not sPlectively extract the potassium chloride from the magnesium chlo-ride ammoniate-glycol filter cake.
The sequence of steps outlined in the previous paragraphs allows for the production of anhydrous magnesium chloride of sufficient quality to be used as cell feed in an electrolysis cell recovering magnesium metal. In ad-dition, it also allows the recovery of potassium chloride of sufficient quali-ty to be used commercially.
Another operation that is pre:Eerred in this invention is the simul-taneous dissolution and precipitation reactions that occur when water-ethylene glycol solutions are added to the original carnallite mineral ores. This mixture is then stirred and maintained at sufficient temperature to allow the solubilization of the mixed potassium and magnesium chloride making up the carnallite mineral ores. This solution, after treatment to remove any remain-ing suspended solids, is then dehydrated by distilling water therefrom, there-by obtaining an anhydrous solution of magnesium chloride in cthylene glycol which may contain up to about 2% potassium chloride ~by weight). From this point on the procedures outlined above are followed to recover both the anhy-drous rnagnesium chloride, and the potassium chloride, as well as to recover and recycle the ethylene glycol, anhydrous amrnonia, the low molecular weight solvent which is used to recover the glycol that is entrained in the magne-sium chloride ammonia complex precipitate, and to remove KCl from this complex precipitate.
It has been found that the use of a carnallite which contains water of hydration, for example MgC12 KCl 6H2O, allows the use of ethylene gly-col without the addition of more water to solubilize the carnallite material containing water of hydration. As an example of such a procedure, we present the possibility of adding sufficient hydrated carnallite as described above to ethylene glycol, such that a solution of magnesium chloride in the ethylene glycol after dehydration and removal of precipitated KCl would be between 8-10 weight percent. This solution is then heated to temperatures sufficient to distill from this solution the water of hydration contained in the original carnallite. ~s this distillation proceeds, the potassiurn chloride precipi-tates from the solution and may be recovered as described above. ~hen the solution is totally anhydrous, the potassium chloride is removed by techniques described or anticipated above, and the magnesium chloride-ethylene glycol solution which may contain up to 2.0 weight percent potassium chloride is treated with anhydrous ammonia to form the magnesium chloride/ammonia complex 3~

precipitate and recovery steps are followed as described above. Subsequent to the recovery steps mentioned, anhydrous magnesium chloride is recovered, ethylene glycol is recovered and recycled, anhydrous ammonia is recovered and recycled, and the low molecular weight solvent for ethylene glycol is also recovered and recycled.
~ he processes developed for the beneficiation of the magnesium/
potassium sul-~ate ores are previously described as recovering economically valuable salts. These two salts are anhydrous magnesium chloride and potas-sium sulfate. This method of the beneficiation of these mixed salts contain-ing potassium and magnesium sulfates comprise the following steps:
(a) Dissolving the mixed double salt containing magnesium and potassium sul-fate in water at a temperature between 50C and 90C and then filtering the insoluble residue from the soiution;
(b) Adding to and dissolving into the filtered solution of step ~a) a molar equivalent to potassium chloride, the molar equivalent calculated on the basis of the solublized magnesium cation requirement for chloride ion, thereby forming a final solution;
(c) Heating the final solution of step ~b) to a temperature within the range of 50C and 90C for a period of time sufficient to allow chemical equilibrium to be established, thereby ~orming an equilibrated solution;
(d) Adding sufficient ethylene glycol to the equilibrated solution of step ~c) to fully dissolve all magnesium chloride calculated to be present in that solution, then removing from the ethylene glycol-water solution the potassium sulfate which precipitated on the addition of said ethylene glycol;
te) Distilling water from the solution of step (d) thereby forming an anhy-drous magnesium chloride solution in ethylene glycol and an anhydrous precip-itate of potassium sulfate, then removing said K2S0~ precipitate from said solution;

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~f) Combining the potassium sulfate precipita~es of steps (d) and ~e) and washing said combined precipitates with sufficient water ~maintained below 70C) to remove entrained ethylene glycol, and recovering the washed potassium sulfate~
(g) Treating the anhydrous magnesium chloride solution in ethylene glycol formed in step (e) with anhydrous ammonia to form a magnesium chloride ammonia complex which precipitates from the ethylene glycol solution;
~h) Removing the complex precipitate from the ethylene glycol and washing it with a low boiling solvent for ethylene glycol to remove any ethylene glycol entrained in the precipitate;
~ leating the magnesium chloride ammonia complex to drive off ammonia leav-ing as a finished product completely anhydrous magnesium chloride.
The sequence of steps outline~ in the previous paragraphs also allows for the production of anhydrous magnesium chloride of sufficient quality to be used as cell feed in an electrolysis cell recovering magnesium metal. In addition it allows for the recovery of potassium sulfate of sufficient quality to be used in commercial grade fertilizers.
Another operation that is preferred in this invention is the simul-taneous dissolution and exchange reactions that occur when the mixed magne-sium and potassium sulfates mineral ores previously mentioned are added to amixture of water and glycol. This mixture is then stirred and maintained at a temperature between 50C and ~0C for a period of time sufficient to dis-solve the mixed double salt of magnesium and potassium sulfates.
To this mixture, after removal of any insoluble residues, either by filtration, centrifigation, or any other technique commonly used to separate solids from liquid solutions, is added sufficient potassium chloride to pro-vide a molar e~uivalent of chloride ion for the solublized magnesiu~n cation present in this mixed solution. The potassium chloride may be commercially .3~'~

obtained or may be obtained from the previously outlined process for the bene-ficiation of carnallite ores, if the two processes are operated simultaneously.
The rate of the dissolution of the added potassium chloride is enhanced by increasing the temperature to at least 50C. A period of time sufficient to allow chemical e~u;libration has been found to be at least 15 minutes at these temperatures.
After chemical equilibration has been established in this solution mixture, any residual precipitates are removed by common solid~ uid separa~
tion procedures. These precipitates contain primarily potassium sulfate. At -~
this point the mixture is dehydrated by a distillation process such that the final solution derived following this distillatioll process is a mixture of an anhydrous potassium sulfate solid precipitate in a solution of anhydrous MgC12 in ethylene glycol.
Again the anhydrous potassium sulfate is removed from this mixture, washed with cold water to recover ethylene glycol, and isolated for sale as a fertilizer. The remaining anhydrous magnesium chloride in ethylene glycol is treated as above, that is, by addition of anhydrous ammonia, separation of the magnesium chloride-ammonia complex from the ethylene glycol, washing the anhy-drous magnesium chloride complex precipitate with a low boiling solvent for ethylene glycol to remove the ethylene glycol entrained in this precipitate, and finally heating the MgC12 ammonia complex to drive off and recover the ammonia and leave as a finished product a completely anhydrous magnesium chloride.
In the practice of this invention, the source of the mixed salts is not particularly important. It is, however, important that the minerals used as raw materials be somewhat free of impurities. ~lowever, it has been found that by following the procedures outlined previously, even these impurities can be precipitated and isolated from the products of these reactions. The _ g _ . .

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impurities normally would be isolated either by initial filtration of a water solution, by the second filtrations or solids isolation following the first addition of glycol to the water solution, or finally isolated following the total dehydration step leading to the magnesium chloride glycol solutions mentioned above.
The reactions mentioned above are limited to those solutions that contain water. A demonstration of this is found in an attempt to accomplish the above reactions and the above beneficiation of the mixed salts containing potassium and magnesium sulfates by the procedures outlined above in totally anhydrous and non-aqueous solvent systems. Those solvent systems checked included methanol, acetone, ethylene glycol, the diethylether of tetraethylene glycol, and tetraethylene glycol. Without the presence of water, no metathet-ical exchange reactions occurred that would be of more than nominal interest.
The organic solvent systems mentioned above were checked both as is and in the presence of aqueous mixtures. There was no reaction between the potassium chloride and the mine~als containing potassium and magnesium sulfate in the organic solvents as is. Water had to be added for the metathetical exchange reactions to occur. However, those reactions made using the solvent as an aqueoussolution provided no additional benefit to the metathetical reactions or their rates that occurred when using only an equivalent amount of water.
The presence of the organic compounds were not found to enhance the metatheti-cal exchange reaction rates.
Various additives were used, and none used seemed to improve the yield or the final brine concentration. The addition of small amounts of polyacrylic acid, ammonium chloride, magnesium chloride, sodium chloride, and calcium chloride had no effect on the extent of the metathetical reaction or the rate of the metathetical reactions. Trace amounts of inorganic acids, such as sulfuric acid and hydrochloric acid, seemed to depress the extent of the reaction as well as the rate of the metathetical exchange reactions.
~ rom the work that we have completed, it would appear that ~he potassium sul~ate ~ormed by the metathetical reactions outlined above or initially present in the mixed salts must be removed from the solution as the reaction proceeds to allow the maximum degree of this metathetical reaction to occur.
~XAMPLES
50 Grams of carnallite ~MgC12 KCl 6~120) was added to 250 grams of ethylene glycol. This solution was heated to the point at which water began to distill from the solu~ion. This distillation was continued until all of the water that had been contained in this precipitate was removed, leaving behind an anhydrous solution which contained magnesium chloride, potassium chloride and ethylene glycol. In this solution was suspended anhydrous potassium chloride. This KCl was removed by filtration and the remaining solution was then cooled to room temperature, and sufficient anllydrous ammonia was added to precipitate from this solution all of the magnesium chloride values obtained therein. After the precipitation of the magnesium chloride/ammonia complex was complete? the complex precipitate was filtered from the solution and washed with methanol saturated with ammonia. This washing removed all of the entrained ethylene glycol contained in the mag-nesium chloride ammonia complex precipitate. The precipitate cake also contains some potassium chloride. Howevcr, this potassium chloride may also be removed by washing with additional methanol saturated with amtnonia.
The potassium chloride recovered in the methanol wash as a solution in methanol may be recovered from said solution by distillation procedures.
Table I presents the results o~ treating the original carnallite-ethylene glyco] mixture mentioned above as outlined.

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TABLE _ Complex Ethylene Glycol Filter Cake Filtrate -Mg 8.75% Mg 0.05%
K0.86% K 1.04%
Cl ~7.26% Cl 2.22%
NH3 56.39%

After MeOH ~sat. NH~ Wash Complex* Filtrate 10Filter Cake Wash Li~uor Mg 11.27% Mg None Detected K 0.43% K 0.09%
Cl 33.82% Cl 0.13%
NH3 ~remainder) * Additional washing can rid the complex filter cake completely of KCl.
EXAMPLES
A typical example of the beneficiation of the mixed double salt con-taining magnesium sulfate and potassium sulfate is outlined below.
2g.5 Grams of a double salt which analy~ed as containing 10.7% mag-nesium and 18.2% potassium, the remainder being sulfate and trace quantities o other salts, was added to 60 grams of water and heated to 80C. This mix-ture was stirred and allowed to dissolve (approximately 5 min.). To this mixture was added 14.9 grams of potassium chloride followed by additional stirring and heating. A reaction time and equilibration time of rom 3 to 10 minutes was allowed. This mixture was then filtered to accomplish a removal of insoluble salts. To the filtrate was added 90 grams of ethylene glycol.
This mixture was then heated until the water began to distill from these mixed :
.~ , ;3~(a solutions. As the water is removed, anhydrous potassium sulfate precipitates from the solution remaining. The distillation is complete when no further water can be removed from the solution mixture remaining~ At that time the entire amount of potassium sulfate initially present has precipitated and the remaining solution is com~osed of anhydrous magnesium chloride in ethylene glycol. This anhydrous solution of magnesium chloride in ~lycol is recovered through a fi~tration or any solids~ uid separation technique of choice while simultaneously recovering the glycol wetted potassium sulfate precipitate.
The potassium sulfate precipitate is given a cold water wash ~temperatures are maintained below 70C) and analyzes at a sufficient quality to be sold as a potassium sulfate fertilizer. The MgC12 solution in ethylene glycol is ex-posed to anhydrous ammonium chloride which precipitates the MgCL2 as a complex whose formula is thought to be MgC12 6NH3. This MgC12 ammonia precipitate is removed from the glycol solu~ion, washed with a solvent for ethylene glycol that is a low boiling solvent, and then heated to temperatures that are suf-ficient to drive off the complexed ammonia. These reactions to isolate the anhydrous MgC12 from the MgC12 ammonia complex are outlined in United States patents 3~983,244 and United States 3~966,888.
Additional work was done which allowed the definition of reactions which would lead to a higher concentration of MgC12 in both the initial brines as well as the ethylene glycol-MgC12 brines. The summary of the reactions `
are given in Table II. This table will outline the amount of double salt reaction with KCl, the amount of water and ethylene glycol used in the reac-tion, the temperatures of the reaction, the extent of the metathetical ex-change, and the effects of any added salts such as magnesium chloride, sodium chloride and calcium chloride.

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~ xamination of Table II and observations made when at~empting to work with more concen~rated solutions of the double salt containing MgS0~ and K2S04 allow us to conceive of a process that would convert only a portion of the double salt magnesium values to anhydrous MgC12 in glycol. The portion of unreacted double salt, unreacted potassium chloride, and the potassium sul-fate product derived from the metathetical excharlge reaction that would be present in the precipitates in the previously described process steps could be recycled back to earlier process steps and s~ill derive the benefits of the invention.
The combination of the above techniques allows the recovery of anhy-drous magnesium chloride by simultaneously treating carnallite ores, as pre-viously described, and mixed sulfate ores containing magnesium and potassium values. Figure I outlines in block diagram form a potential process for accomplishing this benficiation and recovery of high purity, high quality, anhydrous MgC12 suitable for use as electrolysis cell feed in the recovery of magnesium metal. Either anhydrous KCl or anhydrous K2S0~ or a combination of the two may be recovered by this process, depending on the relative amounts of either type of mixed ores are being processed.
; The blocks in the process outlined in ~igure I are meant to repre-sent each of the steps previously described in the separate detailed outline of the individual processes. The benefits of the combined process are as follows: First, only a single processing scheme is necessary to isolate MgC12 (anhydrous) from the MgC12 . 6NH~/glycol slurry formed in both processes.
This eliminates equipment duplication and has obvious economic adv~mtages;
Secondly, the KCl byproduct obtained from the carnallite beneficiation may be used advantageously as a raw material in the initial metathetical exchange reactions required for the beneficiation of the mixed Mg/K sulfate salts;
Lastly, the combination of the two processes allows technical, processing, and economic variability which may be used to advantage depending on pricingand availability of all raw materials.
Although Figure I describes, in diagram form a combination, it is not our intention to be limited by its particular schematic design. Many flexabilities may be anticipated from the diagram as well as the previous descriptions.

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Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the beneficiation of mineral ores contain-ing magnesium and potassium to provide anhydrous magnesium chloride and potassium salt by products which process comprises either:
(A) (a) Dissolving a carnallite mineral ore containing magnesium and potassium chlorides in the minimum amount of water required to obtain complete solubility, thereby obtaining a carnal-lite solution;
(b) Filtering from the carnallite solution of (a) any residual precipitates which are not soluble in said solution, there-by obtaining a filtered solution;
(c) Adding ethylene glycol to the filtered solution of (b) in sufficient quantity to solubilize all MgCl2 present in said filtered solution, thereby obtaining an ethylene glycol-water-carnallite solution;
(d) Dehydrating the ethylene glycol-water-carnallite solution of step (c) by distilling water therefrom, thereby obtain-ing an anhydrous solution of MgCl2 in ethylene glycol which may contain up to about 2.0% KCl (by weight) and a precipitate of anhydrous potassium chloride, said precipitate then being removed and recovered from said solution of MgCl2 in ethylene glycol, thereby obtaining an anhydrous solution of MgCl2 in ethylene glycol; and/or (B) (e) Dissolving a mixed double salt of magnesium and potassium sulfates in water at a temperature between 50°C and 90°C
and then filtering the residue from the solution;
(f) Adding to and dissolving into the filtered solution of (e), a molar equivalent of potassium chloride, the molar equiva-lent calculated on the solubilized magnesium cation requirement for chloride ion, thereby forming a final solution;
(g) Heating the solution produced in step (f) within the range of 50°C - 90°C for a period of time to allow equilibrium to be established, thereby forming an equilibrated solution;
(h) Adding sufficient ethylene glycol to the equilibrated solution of (g) to fully dissolve all MgCl2 calculated to be pres-ent, then removing from solution the K2SO4 which precipitated on the addition of said ethylene glycol;
(i) Distilling water from the solution of step (k) there-by forming an anhydrous MgCl2 solution in ethylene glycol and a precipitate of K2SO4, then removing said precipitate from said solution; and (C) (m) Adding to the anhydrous solution of MgCl2 in ethyl-ene glycol anhydrous ammonia thereby forming a precipitate of MgCl2 6NH3, said precipitate being filtered from solution, washed with a low molecular weight solvent for ethylene glycol, said solvent having been saturated with anhydrous ammonia prior to washing said precipitate, and recovering said washed precipitate of anhydrous MgCl2.6NH3; and (n) Heating the MgCl2.6NH3 of (m) to temperatures suff-icient to drive off all ammonia, thereby recovering anhydrous MgCl2.

2. A process to beneficiate carnallite mineral ores for the purpose of recovering anhydrous MgCl2 and KCl said process comprising the following steps:
(a) Dissolving a carnallite mineral ore containing mag-nesium and potassium chlorides in the minimum amount of water required to obtain complete solubility, thereby obtaining a carn-allite solution;
(b) Filtering from the carnallite solution of (a) any residual precipitates which are not soluble in said solution, there-by obtaining a filtered solution;
(c) Adding ethylene glycol to the filtered solution of (b) in sufficient quantity to solubilize all MgCl2 present in said filtered solution, thereby obtaining an ethylene glycol-water-carnallite solution;
(d) Dehydrating the ethylene glycol-water-carnallite solution of step (c) by distilling water therefrom, thereby obtain-ing an anhydrous solution of MgCl2 in ethylene glycol which may contain up to about 2.0% KCl (by weight) and a precipitate of anhydrous potassium chloride, said precipitate then being removed and recovered from said solution of MgCl2 in ethylene glycol, thereby obtaining an anhydrous solution of MgCl2 in ethylene glycol;
(m) Adding to the anhydrous solution of MgCl2 in ethy-lene glycol anhydrous ammonia thereby forming a precipitate of MgCl2.6NH3, said precipitate being filtered from solution, washed with a low molecular weight solvent for ethylene glycol, said sol-vent having been saturated with anhydrous ammonia prior to washing said precipitate, and recovering said washed precipitate of anhy-drous MgCl2.6NH3; and (n) Heating the MgCl2.6NH3 of (m) to temperatures sufficient to drive off all ammonia, thereby recovering anhydrous MgCl2.

3. A method for the beneficiation of mixed double salts con-taining potassium and magnesium sulfates which allows the recovery of anhydrous MgCl2 and the recovery of potassium sulfate, said method comprising the steps:
(e) Dissolving a mixed double salt of magnesium and potassium sulfates in water at a temperature between 50°C and 30°C
and then filtering the residue from the solution;
(f) Adding to and dissolving into the filtered solution of (e), a molar equivalent of potassium chloride, the molar equiv-alent calculated on the solubilized magnesium cation requirement for chloride ion, thereby forming a final solution;
(g) Heating the solution produced in step (f) within the range of 50°C - 90°C for a period of time to allow equilibrium to be established, thereby forming an equilibrated solution;
(h) Adding sufficient ethylene glycol to the equilibrated solution of (g) to fully dissolve all MgCl2 calculated to be pre-sent, then removing from solution the K2SO4 which precipitated on the addition of said ethylene glycol;
(i) Distilling water from the solution of step (h) thereby forming an anhydrous MgCl2 solution in ethylene glycol and a precipitate of K2SO4, then removing said precipitate from said solution;
(j) Treating the anhydrous MgCl2 solution in ethylene glycol formed in step (i) with anhydrous ammonia to form a MgCl2 -ammonia complex which precipitates from the ethylene glycol solu-tion;
(k) Removing the complex precipitate from the ethylene glycol and washing it with a low boiling solvent for ethylene glycol to remove any ethylene glycol entrained in the precipitate;
(1) Heating the magnesium chloride ammonia complex to drive off ammonia leaving as a finished product completely anhy-drous magnesium chloride.

4. A method according to claim 1, 2 or 3 including the add-itional step of removing trace quantities of potassium chloride from the glycol wet filter cakes of MgCl2.6NH3 which comprises wash-ing said cakes with methanol saturated with ammonia in a quantity sufficient to remove the potassium chloride and the ethylene glycol from said cake.

5. A process for the beneficiation of mineral ores contain-ing magnesium and potassium to provide anhydrous magnesium chloride and potassium salt by products which process comprises:
(A) (a) Dissolving a carnallite mineral ore containing mag-nesium and potassium chlorides in the minimum amount of water re-quired to obtain complete solubility, thereby obtaining a carnal-lite solution;
(b) Filtering from the carnallite solution of (a) any residual precipitates which are not soluble in said solution, there-by obtaining a filtered solution;
(c) Adding ethylene glycol to the filtered solution of (b) in sufficient quantity to solubilize all MgCl2 present in said filtered solution, thereby obtaining an ethylene glycol-water-carnallite solution;
(d) Dehydrating the ethylene glycol-water carnallite solution of step (c) by distilling water therefrom, thereby obtain-ing an anhydrous solution of MgCl2 in ethylene glycol which may con-tain up to about 2.0% KCl (by weight) and a precipitate of anhy-drous potassium chloride, said precipitate then being removed and recovered from said solution of MgCl2 in ethylene glycol, thereby obtaining an anhydrous solution of MgCl2 in ethylene glycol;
(B) (e) Dissolving a mixed double salt of magnesium and potassium sulfates in water at a temperature between 50°C and 90°C
and then filtering the residue from the solution;
(f) Adding to and dissolving into the filtered solution of (e), a molar equivalent of potassium chloride, the molar equiv-alent calculated on the solubilized magnesium cation requirement for chloride ion, thereby forming a final solution;
(g) Heating the solution produced in step (f) within the range of 50°C - 90°C for a period of time to allow equilibrium to be established, thereby forming an equilibrated solution;
(h) Adding sufficient ethylene glycol to the equilibra-ted solution of (g) to fully dissolve all MgCl2 calculated to be present, then removing from solution the K2SO4 which precipitated on the addition of said ethylene glycol;
(i) Distilling water from the solution of step (h) there-by forming an anhydrous MgCl2 solution in ethylene glycol and a precipitate of K2SO4, then removing said precipitate from said solution; and (C) (m) Adding to the anhydrous solution of MgCl2 in ethy-lene glycol obtained in steps (A)(d) and (B)(i) anhydrous ammonia thereby forming a precipitate of MgCl2.6NH3, said precipitate being filtered from solution, washed with a low molecular weight solvent for ethylene glycol, said solvent having been saturated with anhy-drous ammonia prior to washing said precipitate, and recovering said washed precipitate of anhydrous MgCl2.6NH3; and (n) Heating the MgCl2.6NH3 of (m) to temperatures sufficient to drive off all ammonia, thereby recovering anhydrous MgCl2.

6. A process according to claim 1, 3 or 5 including the additional step of washing the K2SO4 precipitates obtained in steps (h) and (i) with sufficient water maintained below 70°C to remove entrained ethylene glycol, and recovering the washed K2SO4.

7. A process according to claim 5, wherein the potassium chloride used in step B(f) is derived from step A(d).

8. A method according to claim 5 including the additional step of removing trace quantities of potassium chloride from the glycol wet filter cakes of MgCl2.6NH3 which comprises washing said cakes with methanol saturated with ammonia in a quantity sufficient to remove the potassium chloride and the ethylene glycol from said cake.

9. In the method of claim 1, 3 or 5, the use of Langbeinite material ore as the source of the mixed double salts containing potassium and magnesium sulfates.

10. In the method of claim 1, 3 or 5, the use of a Leonite mineral ore as the source of the mixed double salts containing potassium and magnesium sulfates.

11. In the method of claim 1, 3 or 5, the use of Schoenite mineral ore as the source of the mixed double salts containing potassium and magnesium sulfates.

12. In the method of claim 1, 3 or 5, the use of Picromerite mineral ore as the source of the mixed double salts containing potassium and magenesium sulfates.