JP2507504C - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Background of the Invention roads, bridges, removal of snow and ice on the sidewalk, and the like, and / or melting is a major work in many areas. Various chemicals have been used to help remove and / or melt snow and ice. Conventional road salts are widely used, in part due to their meltability and also due to their relatively low cost. However, the low cost of salt is offset by the damage caused by its use on roads, bridges, underground cables (e.g., telephone lines or wires), let alone cars. The corrosive nature of the salt damages the pavement and bridge steel structures and surrounding structures. In addition, accumulation in running water causes problems for plant growth. Groundwater accumulation causes health problems in drinking water as the sodium content increases. Other salts, such as calcium chloride, have been used, however, calcium chloride also has similar problems, causing chloride ion accumulation in the environment, which is undesirable. Accordingly, there has been extensive research on alternative non-corrosive, environmentally acceptable and economically viable deicing chemicals. Federal Highway Administration Bjorksten Research on Deicing Chemicals
Sponsored extensive research by the Laboratory (BRL). The report of this study, “Altern
ative Highway Deicing Chemicals, 1980, March, identified calcium magnesium acetate (CMA) as an excellent alternative to road salt.
Since the publication of the L report, various groups and individuals have been studying the preparation and testing of calcium magnesium acetate, deicing agents containing calcium acetate and / or magnesium acetate. (See, for example, U.S. Pat.
, 444,672, 4,511,485 and 4,606,836). However, economically producing CMA on a commercial scale has been problematic. For example, Gancy, Alan B “Preparation of High Quality Calcium
Magnesium Acetate Using a Pilot Plant Process ", Federal Highway Adminis
See tration (1986, January). Dry, large lumps of CMA in the product were problematic as they produced unacceptable levels of temporary dust from the product. For example, 1985, 6, 3, Cedarapids for the Iowa Highway Research Board
Inc. "Continuous Production Calcium Magnesium Acetate / S"
and Deicer ”. Conventional methods have shown unacceptable levels of acid gradients and vapor problems in powdered lime dust and recycled materials, bed materials and products. Conventional calcium magnesium acetate coatings The sand deicing agent used a wetting agent, such as a cement grinding aid, as a binder.Rippie U.S. Patent No. 4,588,512.
See issue. Gancy, U.S. Pat. No. 4,699,725, discloses a magnesium calcium acetate composition and method of making the same. Applicant's U.S. Patent Application No. 003,097, filed January 14, 1987, discloses a deicing composition comprising alkaline earth or alkali metal carboxylate and a method for making the same. The disclosure of US Patent Application No. 003,097 is hereby incorporated by reference. Applicant's U.S. Patent Application No. 77,148, filed July 24, 1987, discloses a deicing composition comprising a calcium magnesium acetate double salt. This US Patent Application No. 77,148 is hereby incorporated by reference. SUMMARY OF THE INVENTION The present invention is directed to compositions containing calcium magnesium acetate double salts that are useful as deicing compositions and methods of making the deicing compositions. The deicing composition of the present invention comprises crystalline calcium acetate, magnesium acetate and a substantially pure double CMA salt substantially free of unreacted magnesium base. In one embodiment, these compositions comprise a CMA double salt that is substantially anhydrous. "Substantially anhydrous" means containing up to about 5% water [or up to about 0.45 moles of water for each mole of calcium or magnesium; for example, CMA double salt is CaMg ₂ (C ₂ H
_With an approximate empirical formula of ₃ O ₂ ) ₆ , this double salt will have no more than 1.35 moles of water per mole of CMA double salt. Compositions containing up to about 2.5% by weight of water are preferred (compositions having the above empirical formula have 0.65 mole of water per mole of calcium or magnesium or about 0.21 mole of water per mole. ). Applicants' finding contrasts with the teaching that CMA compositions desirably have 3 to 4 moles of water per mole of magnesium (thus, CMA compositions having a calcium: magnesium ratio of 1: 2 are about 6 To 8 moles of water or about 20 to 25% by weight of water). See Grancy U.S. Pat. No. 4,694,725. The CMA double salt of the present invention has an approximate empirical formula: Ca _x Mg _y (C ₂ H ₃ O ₂ ) ₂ (x + y) (where x =
3 to 4 and y = 7 to 6). Thus, the calcium: magnesium ratio ranges from about 4: 6 to about 3: 7, preferably from about 3: 6 to about 3: 7. The compositions of the present invention comprise a substantially pure CMA double salt substantially free of crystalline CA and crystalline MA as demonstrated by X-ray diffraction. These compositions also have a thermogravimetric analysis
It is substantially free of amorphous (also crystalline) MA and unreacted magnesium base as measured by gas chromatography-mass selective detector ("TGA-GC-MSD"). (This technique removes the evolved gas through thermogravimetric analysis and
Gas chromatography using a mass selective detector set to 0-200 atomic weight units. See Examples 14 and 15 for further explanation). X-ray diffraction patterns (FIGS. 7C, 7D and 7G) of the compositions of the invention against CA, MA and other CMA compositions (see FIGS. 7A, 7B, 7G and 7F).
Comparison of CA, MA, physical mixtures of CA and MA and other compositions (FIGS. 5A-5C, FIGS. 6B, 6C, 10A-10D,
11A to 11D and 12A to 12D) and the TGA of the present invention.
-GC-MSD spectra (see Figures 6A, 8A to 8D and 9A to 9D) show that the CMA double salt of the present invention is clearly different from other compositions. The CMA double salts described herein have properties that are different from calcium acetate or magnesium acetate or any physical mixture of the two. For example, this C
The MA double salt differs from calcium acetate and / or magnesium acetate in solubility in water. Laboratory studies indicate that this CMA double salt is much less soluble in water than CA or MA. In addition, this CMA double salt was subjected to X-ray crystallography (see the procedure described in Example 16 and FIGS. 7C, 7D and 7F) and TGA-G
C-MSD analysis (step described in Example 15 and FIGS. 8A to 8D and 9A to 9
It seems to have a characteristic crystal structure as evidenced by analytical techniques such as those in Figure D). In addition, these deicing compositions exhibit improved ice-melting behavior beyond that expected for a mixture of calcium acetate and magnesium acetate on a molar basis. This is surprising in view of the poor solubility of the CMA double salt in water. According to a preferred embodiment of the present invention, a bulk density of at least 40 pounds per cubic foot particle specific gravity of 1.2 or greater and an attrition of less than about 3% (ASTM D 4058).
(Measured at -81) is provided. Other excellent handling characteristics of these compositions include having a fairly uniform particle size distribution and low dust and low acetic acid odor. Thus, conventional machines for spraying deicing chemicals, such as road salt, can be used to spray the deicing composition of the present invention. In addition, due to this relatively high bulk density, CMs conventionally used
Unlike compositions containing A, these deicing compositions are less likely to be blown off once applied to snow or ice. (“High Sierra Is Site For Calfrans CMA Tests”, Roads
& Bridges , June 1987, pp. 48-49). In one embodiment, these deicing compositions comprise multiple layers of the CMA composition of the present invention on discrete substrate particles. The substrate particles optionally include a friction aid and / or CMA particles. The present invention also relates to calcium and magnesium bases (a) comprising about 40% by weight of water and having a calcium: magnesium ratio of about 4: 6 to about 3: 7, preferably about 3: 6 to about 3: 7 ("" (B) mixing the mixture of step (a) with about 70 to about 110% of the stoichiometric amount of acetic acid to produce an aqueous mixture of at least about 50% by weight. Producing a CM slurry with water; (c) adding, if necessary, additional acetic acid to give a stoichiometric amount to the CM base; and (d) the slurry of step (c). Aging to allow substantially complete reaction of acetic acid with calcium and magnesium bases; crystalline calcium acetate, magnesium acetate and calcium magnesium acetate double salt substantially free of unreacted magnesium base. It provides a method for forming. Optionally, said method comprises (e)
Drying and pelletizing the slurry of step (d). By "stoichiometric amount" is meant the number of moles of acetic acid (or acetate) required to completely react with calcium or magnesium ions or 2 moles of acetic acid or moles for each mole of calcium and magnesium ions. Acetate. In a preferred embodiment of the method of the invention, in step (b) about 70 to about 95%, more preferably about 90% of the stoichiometric amount of acetic acid is added at once and after mixing the pH is measured (pH is determined). Dilute the CMA slurry with 1 part slurry to 2 parts water before measuring) and about 8
Above 8.5, the pH is increased to about 7 to about 8 by adding more acetic acid.
. 5, preferably from about 7.5 to about 8. Optionally, if obtained is low too pH after aging step (about 6 _^1/2 or less), an increase in the more preferred range by the addition of water reslurried CMA dust (from the following dust collecting device) it can. In a preferred embodiment of the method of the invention, a continuous process is used. In this continuous method,
The slurry is aged by flowing through a reaction train having a sufficient residence time to allow complete reaction of the acetic acid with the CM base. Suitable residence times are in the range of about 3 _^1/2 or 4 hours. Longer residence times can be used if desired. It has been disclosed that hot slurries have advantageous handling properties. Since the reaction between the CM base and acetic acid is exothermic, the heat of the reaction alone results in a slurry temperature in the range of about 130 to 150 ° F. However, if the temperature of the slurry begins to fall below this range, it is beneficial to heat the slurry to at least 130 to 150 ° F, preferably from about 170 to about 200 ° F. If desired, temperatures above 200 ° F. can be used. In the process of the present invention, by simultaneously mixing CM base and acetic acid in essentially stoichiometric amounts in a reasonably diluted aqueous medium, and then aging the resulting slurry,
Substantially complete reaction is obtained and is substantially free of unreacted magnesium base and is substantially anhydrous and also, according to the data obtained by X-ray diffraction and TGA-GC-MSD, indicates that either calcium acetate or magnesium acetate itself can be used. And a CMA double salt composition substantially free of CMA. The result is that the other disclosed methods result in a product having a significant amount of unreacted magnesium base and / or a significant amount of calcium acetate and / or magnesium acetate as determined by the analytical method described above. That's amazing. (See FIGS. 6B, 6C, 10A-10D, 11A-11D, and 12A-12D). As mentioned above, the CMA double salt produced by the method of the preferred embodiment of the present invention is substantially anhydrous and has water on the order of about 5% by weight or less, preferably 2.5% by weight or less (or calcium). And less than about 0.45 mole, preferably less than about 0.21 mole of water for each mole of magnesium and magnesium). This is in contrast to the teaching that CMA compositions desirably have 3 to 4 moles of water per mole of magnesium, and thus at least about 6 to 8 moles of water. For example, US Patent No. 4,699,7 to Gancy.
See No. 25. CMA slurries having a slightly alkaline pH are suitable. About 7 to 8.5
Slurries having a pH are more suitable. A pH having a pH of about 7.5 to about 8 is particularly suitable. This slurry produces a deicing composition with beneficial alkaline pH values that reduces damage to the pavement surface. The slurry also reduces the formation of particles of too large a size in the dispensing and drying process and also advantageously reduces the acetic acid emissions which have to be controlled for environmental reasons. In one embodiment of the method of the present invention, the drying and pelletizing step comprises distributing the CMA slurry in a thin layer over the discrete substrate particles, and drying the substrate particles. The substrate particles may be inert supports, such as abrasion aids, fertilizers (eg, urea, ammonium phosphate, phosphate rock, etc.) or other aggregates; or preformed AEC.
Any of the particles can be included. The distribution and drying steps are repeated to provide multiple thin layers of AEC until the deicing agent has reached the desired particle size. To be fluid and pumpable, the slurry generally contains at least about 50% water by weight. Slurries containing about 55 to about 68% water are suitable. Preferably, the slurry of step (b) is heated to a temperature of about 100 to about 250 ° F; more preferably, about 170 ° C.
To a temperature of about 200 ° F. To be fluid and pumpable, the slurry with low moisture needs to be heated to a higher temperature. The dispensing and drying steps can be performed at substantially the same time. Various materials can be used as the substrate on which the CMA slurry is distributed. Suitable substrates include abrasion aids and preformed CMA particles. Therefore, the method described above rapidly penetrates into ice and has a high enough density to have dimensional uniformity, a substantially isometric shape, and a dust problem with minimal deicing during handling and application. To provide a granular CMA double-salt deicing composition having a pellet hardness as obtained in (1). The deicing compositions produced by the above methods are substantially isometric and have a particle size within a wide or narrow size range with a large or small average size as desired. For example, from a small 48 Tyler mesh (diameter of about 0.295 mm) to
. Deicing compositions having a size range of 371 (5) inches (about 9.5 mm in diameter) can be prepared. In one embodiment, this dimension is in the range of -5 to +28 mesh dimensions. This particle size is suitable because in some cases it is easy to use on conventional machines for spraying deicing compositions. Product size can be adjusted by selecting the appropriate mesh size product sieve. For example, 7-mesh product meets the 90% + 8 mesh specification using (fines); meets the 90% minimum +9 mesh specifications using 7 _^1/2 mesh sieve. Definitions As used herein, the following terms have the following meanings, unless explicitly stated to the contrary. The term "slurry" refers to a solution that contains or does not contain an insoluble suspension.
Shown is a solution of soluble material as high as possible above the saturation point of the soluble material. (See, for example, US Pat. No. 3,333,297). For example, an AEC slurry is an AEC solution or a solution containing both dissolved and undissolved AEC and unreacted raw materials. The use "alkaline earth" refers to an element of group IIa of the periodic table, and includes, for example, beryllium, calcium, magnesium, strontium, barium, radium and the like. The term "alkali metal" refers to an element of Group Ia of the Periodic Table, including, for example, lithium, sodium, potassium, rubidium, cesium, francium, and the like. The term "AE base" refers to an alkaline earth or alkali metal base or a mixture thereof that can react with a carboxylic acid to form a carboxylate salt. Typical AE
Bases include oxides, hydroxides, carbonates and the like of alkaline earth and alkali metal elements. The AE base can include one or more of the individual alkaline earth or alkali metal elements in various combinations and molar ratios. The term "calcium and magnesium base" or "CM base" refers to an AE base in which the alkaline earth or alkali metal moiety comprises calcium, magnesium or a mixture thereof. The term "magnesium base" refers to an AE base wherein the alkaline earth or alkali metal moiety contains magnesium. The term "AEC" refers to an alkaline earth or alkali metal carboxylate in which the carboxylate group has 1 to 4 carbon atoms or mixtures thereof. The term AEC refers to single salts such as calcium acetate, magnesium acetate and potassium acetate, and mixed salts such as calcium magnesium acetate, and the physical mixture or crystallization of single and / or mixed salts. Including things. The term "CA" or "calcium acetate" refers to both anhydrous calcium acetate and its hydrates. The term "MA" or "magnesium acetate" refers to both anhydrous magnesium acetate and its hydrates. The term "calcium magnesium acetate" or "CMA" is an empirical formula Ca _w M
g _z (acetate) _{2 (w + z) wherein} w is moles of calcium and z is moles of magnesium, thus indicating a calcium magnesium acetate composition, and thus of essentially any molar ratio 1 shows a calcium magnesium acetate composition having calcium to magnesium. The terms "calcium magnesium acetate double salt" or "CMA double salt" refers to a salt of calcium magnesium acetate that does not contain a physical mixture of calcium acetate and magnesium acetate when calcium and magnesium are co-crystallized, and this salt is CMA Has an empirical formula consistent with that described above. The CMA double salt appears to have the following approximate empirical formula: Ca _x Mg _y (acetate) _{2 (x + y)} , where x = 3-4 and y = 7-6. The term "calcium-magnesium ratio" or "calcium to magnesium ratio" refers to the ratio of moles of calcium to moles of magnesium. All percentages are weight percentages unless otherwise specified. The term "abrasion aid" refers to a substance that aids and improves abrasion when applied to a slippery surface. Thus, the term includes inert supports having good anti-slip properties and includes sand, ground lime, powdered corn cobs, nut shells (eg, walnut shells, pecan shells, almond shells, etc.), expanded shale, Includes materials such as vermiculite, pumice, cinder, and other substantially insoluble materials having good anti-slip properties. The term "mesh" refers to the mesh size as measured by the Tyler standard sieve series. The term "slurry pH" refers to the pH of a CMA slurry measured by diluting one part slurry to two parts water.

[Brief description of the drawings]   FIG. 1 is a schematic view showing the steps of one embodiment of the present invention.   FIG. 2 illustrates a distributor-dryer combination used in one embodiment of the method of the present invention.
It is an elevation view of a diagram characteristic.   FIG. 3 is a longitudinal section through the drum element of FIG. 2 and its end fittings.   FIG. 4 is a cross-sectional view of the drum element of FIG.   FIG. 5A shows TGA-GC-MSD for crystalline calcium acetate hemihydrate
It is a figure showing a spectrum.   FIG. 5B shows TGA-GC-MS for crystalline magnesium acetate tetrahydrate
It is a figure which shows a D spectrum.   FIG. 5C shows crystalline calcium acetate hemihydrate having a 1: 1 weight ratio and crystallinity
TGA-GC-MSD scan for physical mixture of magnesium acetate tetrahydrate
It is a figure showing a spectrum.   FIG. For the CMA double salt sample of the present invention having B8105-02-6
It is a figure which shows the TGA-GC-MSD spectrum with respect to.   FIG. 6B shows a 1: 1 calcium: magnesium ratio and sample no. B8105-40
CMA sample prepared according to U.S. Patent No. 4,606,836
It is a figure which shows the TGA-GC-MSD spectrum with respect to.   FIG. 6C shows the calcium: magnesium ratio of 3: 7 and the sample no. B8105-40
CMA sample prepared according to U.S. Pat. No. 4,606,836 having -5
It is a figure which shows the TGA-GC-MSD spectrum with respect to.   FIG. 7A shows the X-ray diffraction pattern for crystalline calcium acetate hemihydrate.
FIG.   FIG. 7B shows the X-ray diffraction pattern for crystalline magnesium acetate tetrahydrate.
FIG.   FIG. CMA double salt sample of the present invention having B8105-02-5
FIG. 4 is a diagram showing an X-ray diffraction pattern for   FIG. CMA double salt sample of the present invention having B8105-02-6
FIG. 4 is a diagram showing an X-ray diffraction pattern for   FIG. 7E has a calcium: magnesium ratio of 1: 1 and a sample no. B810
FIG. 4 shows an X-ray diffraction pattern for a CMA sample having 5-02-4.   FIG. 7F has a calcium: magnesium ratio of 3.3: 67 and is prepared at low temperature.
And sample No. X-ray diffraction pattern for CMA sample with B5669-23-2
FIG.   FIG. 7G shows the CMA double salt sample of the present invention without the stacked crystalline CA peak points.
FIG. 3 is a diagram showing an X-ray diffraction pattern according to the present invention.   8A to 8D show CMA double salts of the present invention prepared by the method described in Example 10.
It is a figure which shows the TGA-GC-MSD spectrum with respect to a sample.   9A to 9D show CMA composites of the present invention prepared by the method described in Example 10A.
It is a figure which shows the TGA-GC-MSD spectrum with respect to a salt sample.   FIGS. 10A to 10D show TGA-G for commercial CMA samples from Verdugt.
It is a figure which shows a C-MSD spectrum.   Figures 11A-11D were prepared according to U.S. Patent No. 4,699,725 2:
TGA-GC-M on CMA sample with calcium: magnesium ratio of 8 It is a figure showing SD.   Figures 12A-12D were prepared according to U.S. Patent No. 4,699,725:
TGA-GC-M for CMA samples with a calcium: magnesium ratio of 2
It is a figure showing SD.   Detailed description of the invention   Preparing a fluid, pumpable CMA slurry and then the CMA
The method according to the invention comprises drying the slurry and pelletizing the slurry.
A CMA double salt composition was prepared. Discontinuous substrate particles (optionally CMA or abrasive
At least about 130 to about 150 ° in a thin layer.
F, preferably CMA having a temperature of about 170 to 200 ° F.
Drying the substrate particles to produce a granular (or pelletized) deicing composition.
Therefore, it is preferable to dry and pelletize the CMA slurry.   Manufacture of CMA slurry   Typically, the CM base, acetic acid and water are mixed, preferably in a stirred vessel.
To prepare a CMA slurry. Preferably the CM base and water are mixed first
And a flowable aqueous CM base mixture typically comprising at least about 40% by weight of water
Acetic acid is then added. The CM base is reacted with a sufficient stoichiometric amount of acetic acid.
Provides complete reaction of CM base and minimal acid vapor loss and also has low corrosivity
A CMA slurry having a pH that results in a CMA composition that does Preferably acetic acid pair
The ratio of CM bases is carefully adjusted to produce a substantially complete reaction of CM bases and
Minimize volatilization of unreacted acids during distribution and drying steps. Therefore, adding enough acetic acid to add C
PH from about 7 to about 8.5, more preferably from about 7.5 to 8.0 upon reaction with M base.
(When 1 part slurry was diluted in 2 parts water) resulting in a CMA slurry having
There is no acid odor. Optionally, re-collected (during the distribution and drying process) by dust collection equipment
Slurry CMA dust may be added to the slurry. This addition is usually about 8.5 or less.
The slurry pH can be increased to 8.5 or higher without increasing the insolubles seen at the above pH values.
You. This slurry has a pH of about 9 to about 10 (when 1 part product is diluted in 9 parts water,
) To give the finished CMA product.   Slurries with low pH values (approximately 5 to 6) may produce products that are too large during the distribution and drying process Of acetic acid and results in high acetic acid emissions which are unacceptable from an environmental point of view. This slurry
Produces unacceptable corrosive products which, when used for deicing, are not
Causes screeching.   A pump that does not solidify by adding sufficient water, either alone or as part of an acetic acid solution
Produces usable slurry. Slurry that does not have enough water suddenly, especially when heated
To solidify. Water having a slurry of about 50% by weight or less (about 30 moles of water per mole of CMA)
Excessive thickening of the slurry occurs at about 170 ° F.
As lower slurry moisture is used, the resulting slurry is heated to a higher temperature
Must. Thus, a slurry having at least about 50% water is suitable
I have. CMA slurries having about 55 to about 68% water are particularly suitable. Greater than
A CMA slurry with a significant amount of water can be used, but this extra water is later dried
Slurries that must be removed in the process and therefore have a high water content will have increased drying
Cost is less economical and beneficial. Also use lower slurry moisture
Requires heating the resulting slurry to a higher temperature before the distribution and drying steps.   Suitable CM bases are calcium, magnesium oxides, hydroxides, carbonates and the like.
Include these mixtures in various molar ratios.   Preferred CM bases are dolomite lime, hydrated dolomite lime, preferably S-form hydrated lime.
Contains lomite lime and magnesium oxide.   Suitable CM bases include insoluble acetate salts, such as iron and aluminum.
It has low impurities.   The preferred form of acetic acid is a dilute solution of acetic acid (as low as about 10%) and concentrated acetic acid, such as vinegar.
Acid and acetic acid solutions with intermediate concentrations. Acetic acid used here is a chemical method
Or by another method such as fermentation of cellulosic substances by microorganisms etc.
Wear. Acetic acid produced by another method, such as microbial fermentation, is a conventional method used in chemical engineering
Is more cost-effective than the more concentrated acetic acid produced in
Possible increase due to the need to further evaporate the water in order to obtain a dry product
The economic disadvantages of reduced drying costs will be overcome.   Suitable acetic acid includes glacial acetic acid.   The CMA slurry is aged to allow complete reaction of acetic acid and CM base. Acetic acid Aging the slurry when using reactive CM bases with relatively short reaction times
Preferably. This may take several containers before reaching the drying and pelletizing process.
By flowing through the reactor train. From about 3.5
Reactor train with 4 hours residence time allows complete reaction of CM base with acetic acid
Give more than enough time. On the order of about 10 to about 13 hours, as desired
Or longer reactor trains having longer residence times can be used.   Production of deicing composition from CMA slurry   Preferably, the fluid, pumpable CMA slurry is from about 100 to about 250
° F, preferably about 150 ° F, more preferably about 170 to about 200 ° F.
Heat each time. Surprisingly, relatively high temperatures, preferably from about 170 to about 2
Heating the CMA slurry to 00 ° F. results in efficiency in the dispensing process that follows, and therefore yield.
Found to improve the rate. In addition, when preparing CMA, high slurry temperatures
Has been found to result in the production of a higher proportion of CMA as a CMA double salt.
Was. Further, when the slurry is not heated to a sufficiently high temperature, for example, at about 100 ° F.
When heating below, most of the slurry in the distribution process forms a thin layer on the substrate particles.
It becomes dust rather than forming. Use this dust in a baghouse or wet scrubber
Must be collected in a highly efficient dust collector such as
Recirculate. Thus, the overall amount of water that must be removed in the drying process increases.
In addition, this increases manufacturing costs.   In addition, another beneficial effect of operation at high slurry temperatures is the low hardness of the CMA coating.
50% increase in high slurry temperature operation compared to slurry temperature operation
did. The increase in hardness of the CMA coating is due to product transport and dust during storage.
A product was provided that could well resist degradation to form fines.   As mentioned above, the CMA slurry remains fluid and pumpable and solidifies
The CMA slurry must contain enough water to avoid. This slurry is
Generally contains at least about 50% water. In particular, about 55 to about 68% water
Slurry is suitable. Low slurry water content also results in higher dust and fines in the distribution process.
This causes the formation of fines. Slurry water content higher than necessary reduces drying costs and increases
Production efficiency.   In one embodiment of the method of the present invention, the CMA slurry is distributed over discrete substrate particles.
To form a thin layer of CMA on the substrate particles. About 0 to 100 psig, preferably about 0
Approximately 20 psig of atomizing air can be used. Surprisingly, slurry on substrate particles
The elimination of the use of excess atomizing air when dispensing results in an increased product and also
It has been found that it reduces the amount of dust and slurry that becomes fine. Preferably, CM
The thin layer of A substantially surrounds the substrate particles and forms a substantially continuous layer.
You. Next, the layered substrate particles are dried. The desired particle size is obtained for the deicing composition
Dispensing and drying steps while adding an additional thin layer of CMA at each dispensing and drying cycle
The layered substrate particles are recirculated through the substrate to produce multiple CMA layers on the substrate particles.
Cheating.   Suitable base particles are inert supports such as abrasion aids, fertilizers (eg urea, phosphoric acid)
Ammonium, phosphate rock, etc.) or other aggregates or preformed CMA
Particles. Particularly preferred substrate particles are sand, especially sand of -10 to +20 mesh size.
, And preformed CMA particles. Preformed CMA particles are used in this method
Crushing and deactivating deicing compositions having a layer of CMA, such as those made from
Obtained by separating the CMA material from the sexual support (if any). Place
Recycle a designated portion of the desired sized product to obtain oversized particles, which are then ground
To provide a source of preformed CMA particles
Is provided.   The dispensing and drying steps can optionally be performed simultaneously, e.g. in the presence of heated gas
Distribute the thin layer of CMA slurry on the substrate particles by using
Can be done separately.   In one preferred embodiment, the dispensing and drying steps are performed substantially simultaneously. In this specific example,
In the presence of a heated gas (e.g., air)
Distribute the slurry. This occurs at substantially the same time that the slurry is distributed in a thin layer on the substrate particles.
The heated gas contacts the substrate particles. Slurry droplets are distributed over the substrate particles
And the water spatters leaving a dry coating of CMA on the substrate particles. Base
Flow rate and temperature of the gas heated so that water scatters from the thin layer of CMA slurry on the material particles
Adjust the degree. Optionally, the small substrate particles are re-combined through a combined distribution and drying process.
Circulation C. to the extent necessary to produce the desired particle size for the product of substantially equal size
Provides an additional layer of MA. Product if preformed CMA constitutes substrate
Of large or large particles to obtain a continuous source of preformed CMA particles
Alternatively, small particles can be used without grinding.   The layered substrate particles are sieved to remove fines, which are recirculated to remove CMA
Accept additional layers; feed bulk material to suitable grinder.   Having various ratios of individual alkaline earths and alkali metals using this method
Since deicing agent can be prepared, adjust the type and amount of alkaline earth and alkali metal.
The desired content of individual alkaline earths and alkali metals is produced. Therefore, it is used here.
The alkaline earth base used can be adjusted from about 4: 6 to about 3: 7, preferably about 3: 6
Deicing composition comprising a CMA double salt having a calcium to magnesium ratio of from about 3: 7
Produce things.   FIG. 1 shows one embodiment of the method of the present invention.   FIG. 1 shows a preferred device for controlling the speed of flow to the mixing tank 12.
Water is supplied through line 10. At the same time, the CM base (“A
E base No. 1 ") and if more than one CM base is used, line 16
Through the CM base No. 2 (“AE base No. 2”) into tank 12. Additional
If additional CM bases are used, they may be added to tank 1 through additional supply lines.
2 can be supplied. This mixture is passed through line 18 to an optionally stirred reactor 22.
To fill. Acetic acid ("carboxylic acid") is fed to reactor 22 through line 20
, Thereby reacting with the CM base to produce a CMA slurry. This CMA slurry
The surge tank 26 is filled through the line 24. Collected from dust collector 66
Dust is supplied to the surge tank 26 together with additional water when instructed.
The heating device 28 heats the slurry in the surge tank 26. A suitable heating device 28 is
Including a steam jacket, steam coil or other heating device. Sprayed slurry contacts
Strikes a dense curtain of cascaded substrate particles from lifter 36 in vessel 34
Surge through line 30 through spray nozzle 32 located in contactor 34 as
Pump heated CMA slurry from tank 26. Substrate particles pass through line 38
To enter the contactor 34 or the layered substrate particles enter through the recirculation line 40. This layer
Conversion The substrate particles are dried in the dryer 42. The gas flow is passed through line 44 through heating device 4.
6 (where heated by natural gas or other suitable heating device),
The heated gas is then withdrawn through line 48 into dryer 42. Suitable
In a specific example, the contactor and dryer are used to dry the substrate particles immediately after coating.
(See FIGS. 2 to 4). In another embodiment, the contactor and dryer are
is seperated. The layered substrate exits the dryer through line 50 and enters separator apparatus 52
. Separator device 52 is removed and lined into contactor 34 for additional coating
Remove the fines returned through 54-40. Larger substances pass through line 56
Enter mill 58 (preferred mills include hammer mills or roll mills) and then
And returns to contactor 34 through line 60-40. Draw the product through line 62
Discharge and then send to transport and storage. (If the base particles contain CMA particles,
If desired, the designated portion of the product is recycled to contactor 34 to obtain a large material which is
To yield CMA substrate particles). Alternatively, rotating drum cooler or flow
The product can be cooled in a floor cooler or other suitable cooling device.   Continuous supply of substrate particles to contactor 34 through line 38 (or recirculation 40)
I do. By adjusting the amount of material in the contactor 34 and the internal structure of the contactor 34,
Minimize return and provide the most uniform level of coating on each particle.   Air and dust are removed from dryer 42 through line 64. Dust collector
The dust is collected by the device 66. A suitable dust collector device 66 is, for example, a bag house.
, Wet scrubbers or other conventional dust removal systems. Through line 68
To discharge air to the atmosphere (outside). Recover dust collected by the dust collector
Return to the surge tank 26 through line 70. (Alternatively, dust collection
If the equipment includes a wet scrubber, run a mixture of CMA dust and water through a conduit.
To the mixing tank 12).   In the method for producing the deicing composition of the present invention, a preform comprising a friction aid
Either small or small CMA particles or inert supports can be used as substrate particles
.   2 to 4 show a combination dispensing-drying suitable for use with the preferred embodiment of the present invention.
1 shows a drying device. This device is more fully described in U.S. Pat. No. 3,333,297 to Tytus et al.
Minutes, which is here inserted as a reference.   In summary, the combination dispensing-drying device shown in FIGS. 2 to 4 is mounted for rotation.
Including a hollow elongated drum 102. The substrate is passed through the conduit 104 through the drum 10
Enter 2. The vanes 106 are conduits 104 towards vanes 108 lining the drum 102.
To help transfer substrate transferred. The blade 108 is shown in cross section in FIG. Conduit 11
0 to transfer the CMA slurry to the spray nozzle 112. About 0 to about 100 psig, good
Preferably, a spray air pressure of about 0 to about 20 psig can be used. Extra spray with spray nozzle
It is particularly preferred not to use mist air. Do not use extra atomizing air.
It has been found that it reduces the amount of slurry that becomes strikes and fines. About 20 with spray nozzle
To 80 psig atomizing air is used because the coated substrate product does not stick to the lifter and
This was thought to be necessary to help the slurry adhere to the material particles.
It is amazing. A conduit 113 provides hot gas to the drum. Drum 10
2 rotates, the blades 108 vertically and vertically extend the drum to separate the substrate particles with a curtain.
Acting as a shower, the curtain moves across the drum. Slurry
Is sprayed through a nozzle onto a plurality of moving curtains of substrate particles and onto the particles
The thin layer is dispensed, which is dried by hot drying gas passing through the drum.
Substrate particles traverse drum 102 and reach dam 114 at the exit end of drum 102
This spraying and drying action is repeated as the temperature increases. Manifold 116 is hot gas and substrate
Accept both particles. The substrate particles enter the receiving device 118 and are sieved therefrom.
And, if indicated, recirculated through drum 102.   In another embodiment of the present invention, separate dispensing and drying devices are used. Separation distribution
Appropriate equipment for drum granulators, bread granulators, pug mills and other conventional granulators
And pelletizer. Suitable separation dryers include rotary drums and fluid bed dryers.
And devices for drying other conventional pelletized or granulated materials. Slurry on top
Use of this device with sufficient substrate particles to produce a rotating bed of substrate particles
You. Enough to build up a layer on the substrate particles to give the product of the desired dimensions
The device is adjusted to produce a recirculation ratio.   Continuous production of CMA double salt   In a preferred embodiment of the present invention, the unreacted magnesium base is substantially free and free of magnesium.
A substantially pure CMA double salt that is anhydrous in nature is produced by a continuous process.   Water, calcium and magnesium bases (eg, calcium oxide, magnesia
C. and dolomite lime) are continuously mixed to produce an aqueous CM base mixture.
Sufficient water, at least about 40% by weight water, is added to produce a flowable mixture.   The CM base mixture and about 70 to about 110% stoichiometric acetic acid are co-
About 1.8 moles of acetic acid per mole of calcium and magnesium (stoichiometric
(90% of the amount). The rate at which too little acid is added or acid is too slow
If it is added as a by-product, by-products form and precipitate (for example, calcium precipitate as a white precipitate).
Um acetate and magnesium acetate as an amorphous precipitate).   Maintain a slurry pH of about 7 to 8.5, preferably about 7.5 to 8, as needed
Add additional acetic acid for Monitor slurry pH; 2 parts water and 1 part slurry
After diluting the slurry, the pH of the slurry thus diluted is measured.   This slurry is then ionized with acetic acid and for a time sufficient to permit substantially complete reaction.
Let the ri ripen. Make sure that the total residence time is sufficient for a virtually complete reaction.
This aging can be accomplished by flowing the slurry through a vessel of
. A residence time on the order of about 3.5 to 4 hours has been found to be sufficient:
Longer times (on the order of about 10 to about 15 hours) can be used. Acetic acid and CM salt
The heat of reaction of the group produces a slurry temperature of 150 ° F. or higher and about 170 to 200 °
F; however, maintaining the temperature within the preferred range during the aging step;
It is desirable to heat the slurry to maintain its fluidity.   After aging, a temperature of at least 150 ° F., preferably from about 170 to about 200 ° F.
Heat the slurry each time (if necessary). Next, this slurry was used as described above.
Distribute onto the timber particles and dry.   Calcium magnesium acetate double salt   A substantially pure crystalline CMA complex having a calcium to magnesium ratio of about 1: 2
Compositions of the invention comprising salts differ from CA, MA and physical mixtures of CA and MA
Not only, but also not made from other methods and not substantially pure CMA double salt.
Shows several properties that differ from the CMA composition.   The substantially pure CMA double salt of the present invention has a crystalline CMA as demonstrated by X-ray diffraction.
A and substantially no crystalline MA. This X-ray diffraction technique is described in Example 16. The substantial absence of CA is about 5.2 ° and 7.4 ° 2θ, with the strongest peak of crystalline CA.
Marked by the substantial absence of the mark. The substantial absence of crystalline MA is about 12.5
From 13 ° 2θ by the substantial absence of the strongest peak of crystalline MA
It is. Instead, the characteristic very strong dual-pi within the range of 2.75-8.
Are observed for the crystalline double salt; these peak positions are about 9.1 and 9.1.
The center is at 8 ° 2θ.   The amounts of the crystalline CA and MA impurities can be specified from the X-ray diffraction pattern. so
Then, the peak intensities for the CMA peaks located at about 9.1 and 9.8 ° are both changed.
Plus the peak intensity plus the CA peak located at about 5.2 and 7.4 °
Compare to twice the peak intensity for MA centered at about 12.7 ° 2θ. Real
The above pure crystalline double CMA salt is less than about 8%, preferably less than
Has a percentage of impurity peaks equal to or less than about 5%.   The substantially pure crystalline CMA double salt of the present invention can also be measured by TGA-GC-MSD.
An amorphous (and crystalline) MA-free and unreacted magnesium salt
Contains no groups. This technique removes the released base from thermogravimetric analysis (TGA) and removes it.
Selective detector (TGA-GC-M) set at 15 to 200 atomic weight units
These are subjected to gas chromatography using SD).   As discussed in Examples 14 and 15, CO_TwoAnd / or T by mass with respect to acetone
When monitoring GA-GC-MSD, the substantial absence of MA is 29-35 minutes
Ie, at about 290 to 350 ° C., as evidenced by the substantial absence of a peak. same
Sometimes unreacted magnesium base, Mg (OH_Two) Or magnesium oxide hydrate
Produces a peak at about 300 ° C. when present. Approximately 1 layer compared to CMA
Unreacted magnesium base in an amount of at least% by volume can be detected by this technique. Unreacted salt
The group is found in some of the products generated by the direct reaction method disclosed by others
Are not found in the products produced using the slurry method of the present invention.   The amount of MA and magnesium base impurities can be calculated from TGA-GC-MSD
. The resulting acetone spectrum is monitored to calculate the amount of MA impurity. M
Surface under peak at about 29 to 39 minutes (about 290 to 350 ° C.) corresponding to impurity A
Area under all acetone peaks from 20 to 45 minutes (200 to 450 ° C.)
To Compare. Thus, MA acetone release can be measured as a percentage of total acetone release.
You. Calculated in this manner, substantially pure crystalline CMA double salt contains 5% of this MA impurity.
% Or more. To calculate the amount of magnesium base impurities, the resulting water
Monitor the spectrum. The area under the peak that appears at about 300 ° C is magnesium hydroxide
Corresponds to water from uranium or magnesium oxide impurities. Substantially pure crystalline CM
Double salt A is less than about 3% by weight of CMA, preferably less than about 1% by weight of magnesium.
Has this percentage of base impurities.   As noted above, the substantially pure CMA double salt of the present invention includes substantially all of the following:
None: crystalline CA; crystalline and amorphous MA; and unreacted magnesium base.   More particularly, a substantially pure CMA double salt meets the following criteria: 1. As demonstrated by the X-ray diffraction pattern, this is the difference between crystalline CA and crystalline M
Substantially free of A, ie the sum of two strong CM peaks (as discussed above)
The sum of the impurity peaks for CA and MA is about 8% or less, preferably about 8%.
5% or less. 2. As determined by TGA-GC-MSD, this converts amorphous (and crystalline) MA
Substantially free and free of magnesium base, i.e. MA acetone release is
Less than 5% of the ton emission; and magnesium base impurities (water release at about 300 ° C.).
Is less than about 3% by weight of the CMA sample, preferably less than 1% by weight.
.   A substantially pure CMA double salt composition comprises crystalline CA, crystalline MA, and crystalline CA.
Comparing with a physical mixture of MA (see FIGS. 5A, 5B and 5C, respectively); or
Compared to CMA compositions made by other methods (see FIGS. 6B and 6C)
, When performing a TGA-GC-MSD analysis (see FIG. 6A)
Show.   The TGA-GC-MSD analysis shown in FIGS. 5A to 5C and FIGS. 6A to 6C
Acetone and carbon dioxide (acetate over time) at a constant heating rate of 10 ° / min.
The relative ion abundance of the main degradation product) is plotted. Acetone present
GC-MS by reducing carbon dioxide abundance by a factor of 3 to match the degree scale
2 shows the fine structure of the D chromatogram. A description of this method is further seen in Examples 14 and 15.
It is.   FIG. 5A shows a TGA-GC-MSD analysis for crystalline CA hemihydrate. Base
Essentially, CA decomposes on heating to produce acetone and calcium carbonate:
Lucium further decomposes to form carbon dioxide. Very small amount of carbon dioxide plotted
Note that it is detected during the specified time frame. Most of the carbon dioxide is in the fifth
Emitted at higher temperatures (approximately 600-800 ° C.) than those shown in FIG.   FIG. 5B shows TGA-GC-MSD for crystalline MA. MA is almost CA
, Except that magnesium carbonate decomposes at lower temperatures and therefore
CO generated_TwoIs detected during the plotted time frame.   FIG. 5C shows the TGA-GC-MSD for a physical mixture of CA and MA.
Mixture was prepared by grinding together CA and MA with 1: 1 weight ratio
.   FIG. 6A shows TGA-GC-MSD analysis for CMA double salt according to the present invention.
. Comparison with the analysis shown in FIGS. 5A, 5B and 5C shows that this sample has the least amount of CA and M
A is shown.   The proposed decomposition mechanism or reaction scheme is as follows:       Ca_xMg_y(C_TwoH_ThreeO_Two)_{2 (x + y)}  → xCaCO_Three  + YMgO +                2 (x + y) CH_ThreeCOCH_Three   + YCO_Two (At 300-500 ℃)                xCaCO_Three → xCaO + xCO_Two (At 500-800 ℃)   Assuming the above equation, the x / y ratio was calculated from the TGA data to be 0.55.
This is in good agreement with the result of elemental analysis of the 0.52 sample. Therefore, TGA-G
C-MSD indicates that this sample has a calcium to magnesium molar ratio of about 1 to about 2.
It is a substantially pure calcium magnesium acetate double salt.   FIG. 6B illustrates the process disclosed in U.S. Pat. No. 4,606,836 ("Direct Reaction").
Has a calcium to magnesium acetate ratio of about 1: 1 produced by
2 shows a TGA-GC-MSD analysis of a CMA sample. 5A and 6A ratio
By comparison, this sample shows peaks monitored at about 40 and 42 minutes with the molecular weight of acetone.
, Contains significant amounts of residual CA.   FIG. 6C shows a 3: 7 calcite produced by the same direct reaction method as the sample of FIG. 6B.
4 shows a TGA-GC-MSD analysis of a CMA sample having a ratio of U to Mg.
This sample is also not of the present invention. From comparison with Figures 5A, 5B and 6A
, It can be seen that this trial contains significant amounts of both residual CA and MA.   When subjected to analysis by powder X-ray diffraction, the crystalline CMA double salt of the present invention has a crystalline C
A and crystalline MA and a CMA composition that is a substantially impure CMA double salt (No. 7)
A to 7G) have a characteristic pattern.   From the X-ray diffraction patterns shown in FIGS. 7A to 7F, crystalline CA, crystalline MA and
It can be seen that all CMA double salts show characteristic X-ray diffraction patterns. Further explanation of the method
Is described in Example 16. Table XIII summarizes the peak positions for the CMA double salts of the present invention.
I do.   FIG. 7A has two strongest peaks at 2θ of about 5.2 ° and about 7.4 °,
3 shows an X-ray diffraction pattern for crystalline CA hemihydrate.   FIG. 7B shows the X-ray diffraction pattern for crystalline MA tetrahydrate. This is 2θ
It shows the strongest peak from 12.5 to 13 °. Amorphous MA is centered at about 10 ° 2θ
Shows a strong and broad diffraction peak.   FIG. 7C shows the X-ray diffraction for CMA double salt according to the present invention. In this figure the crystal
The sharp vertical lines to the peak position corresponding to the gender are stacked. Double salt is 2θ8.
It shows a characteristic very strong double peak in the range of 75 ° to 10.5 °. these
Are centered at about 91 ° and 9.8 °. Strongest crystalline MA peak present
No, indicating that this sample appears to contain substantially no residual crystalline MA. two
Very low, consistent with the 2θ range of the two strongest CA peaks (5.2 ° and 7.4 °)
High intensity peaks indicate that this sample contains only very small amounts of residual crystalline CA.
Thus, it appears to consist of substantially pure CA double salt.   7D also shows the X of the CMA double salt according to the present invention stacked with crystalline CA peak points.
2 shows line diffraction. This sample has a 2θ of 8.75 to 10.5 ° characteristic of CMA double salt.
A strong double peak is shown within the range. Match 2θ range for strongest crystalline peak
Strongest crystalline MA peak associated with the presence of a very very low intensity peak
Is that this sample has virtually no residual crystalline MA and only a very small amount
4 shows that it contains substantially pure CMA double salt with crystalline CA.   FIG. 7E shows a 1: 1 calcium to magnesium produced by the slurry method of Example 7.
3 shows an X-ray diffraction pattern of a non-inventive CMA sample having a film ratio. This trial The diffraction pattern of the material shows the double peak characteristics of the CMA double salt, but also
Peaks of moderate intensity corresponding to the two theta values of the two strongest peaks and of the crystalline MA
The low intensity peak corresponding to the 2θ range of the strongest peak is shown. Hence that
Examination of the X-ray diffraction pattern shows that while this sample contains a CMA double salt,
It also contains moderate amounts of crystalline CA and some crystalline MA, so this is
It does not appear to be a qualitatively pure CMA double salt.   FIG. 7F has a calcium to magnesium ratio of 3 to 7 but low temperature according to Example 11;
2 shows an X-ray diffraction pattern of a CMA sample not of the present invention manufactured by the method of the present invention. this
The diffraction pattern of the sample shows a double peak characteristic of CMA double salt,
A shows a peak of moderate intensity corresponding to the 2θ range of the two strongest peaks of A.
Thus, this sample contains a moderate amount of crystalline CA and substantially pure CMA
It is not a double salt.   FIG. 7G shows the present invention without a stacked line corresponding to the peak position of crystalline CA.
Figure 3 shows the X-ray diffraction pattern of a bright CMA sample. In this example, the pattern is crystalline CA and
And the absence of MA. As mentioned above, Table XIII shows these peak positions and intensities.
Summarize.   Further, heating the CMA slurry to a relatively high temperature during the process of manufacturing the deicing composition.
Has a higher proportion of crystalline CMA double salt compared to CA and / or MA
It has been discovered that this results in a deicing composition. See Figures 7C, 7D, 7F and 7G
.   FIG. 8 shows the TGA-GC-MSD spectrum for the CMA sample produced according to Example 10.
Indicate the coutle. FIG. 9 shows TGA-G for CMA samples prepared according to Example 10A.
3 shows a C-MSD spectrum. FIG. 10 shows a commercially available CMA manufactured by Verdugt.
3 shows a TGA-GC-MSD spectrum for a sample. Figure 11 shows Gancy's United States
Patent No. 4,699,725, Example II containing about 2 to 8 calcium to magnesium
1 shows a CMA sample produced by the method of I. FIG. 12 shows Gancy U.S. Pat.
No. 699,725, to the method of Example IIB containing about 1: 2 calcium to magnesium.
3 shows a CMA sample produced from   Part A of each of these figures shows the total ion count. Part B in the figure is time
Therefore CO generated as a function of temperature_TwoIs shown. Part C of the figure is time, and therefore temperature Shows the water generated as a function. Part D of the figure is emitted as a function of time and hence temperature.
Indicates the produced acetone.   As can be seen by comparing FIGS. 8 to 11, the book is shown in FIGS. 8D and 9D.
Samples produced by the method of the invention produce acetone spectra in less than 35 minutes (about 350 °).
Virtually no peaks in the cuttle, and therefore substantially magnesium acetate
Absent. As shown in Figures 10D, 11D and 12D, commercially available samples and opened by others
All of the samples prepared by the indicated method show significant MA peaks.   Table 16 shows X-ray diffraction and TGA-GC-MSD for some samples of CMA.
Show data. The data are X-rays for CMA double salt at 9.1 and 9.8 ° 2θ
The peak intensities and the peak intensities for the crystalline CA impurities in these samples (5.2
And a peak located at 7.4 ° 2θ). In this table, measured by TGA
The amount of water in the sample and the
The amount of MA is indicated as measured by the ratio of ton peaks. This MA aceto
Release is calculated as a percentage of total acetone release. None of these samples
It has no reactive magnesium base and therefore does not show this data.   Samples A00636, B00796, B00801, and K-10-11-87
A sample of substantially pure crystalline CMA double salt. Other samples were marked by X-ray diffraction data.
MA was determined from acetone data generated from large amounts of crystalline CA or TGA-GC-MSD.
Shown; these samples clearly show that they are not substantially pure crystalline double salts.   An example   The following non-limiting examples are representative of deicing compositions made by the method of the present invention. Virtually
Using an apparatus having a combination dispensing and drying device as shown in FIGS.
Examples 1 to 7 and Example 10 were produced.   Unless otherwise specified, after diluting the slurry with one part slurry to two parts water,
The pH of the diluted slurry was measured.                                 Example 1 Batch production of calcium magnesium acetate on sand   Calcium Magnesium Acetate (CMA) slurry
Manufactured by the H method. The ventilated reaction tank was stirred with 72 gallons of water. S type water 150 pounds of Japanese dolomite lime was gradually added. Raw suspension of lime in water
I did Pump technical grade glacial acetic acid into the tank at a rate of approximately 1.0 lb / min.
Was sent. As the acid is added, the heat of acid-lime reaction increases the temperature of the mixture
Occurred. When 186.5 pounds of acid was added, the slurry became too thick. Sura
The re-temperature was 130 °. An additional 8 gallons of water was added to dilute the slurry. Acid total
Acid addition was resumed until 239 pounds were added. The slurry pH is 8.2 at first and
It rose to 8.8 after passing through. The slurry moisture was 68%. This water is mass
Slightly lower than calculated by balance, indicating that a small amount of evaporation had occurred
. Subsequent batches of slurry were made similarly, but to avoid thickening during the reaction stage
More water was added at the start.   Next, CM was added to the granular deicing composition containing CMA coated on sand by the following method.
Convert A slurry. Pilot plant 3 feet in diameter and 12 feet in length
A rotating drum was used. This drum has internal lifters, internal dams and external solids
Equipped with a circulation system. Bag How on fan, inlet air heater and outlet air
An air system consisting of a dust collector was also included.   No. Charge 500 pounds of 2 sand blasting grade sand into this rotating drum
Was. The system was preheated to about 150 ° F. Falling car of sand particles in rotating drum
A CMA scan at a temperature of about 112 ° F. is applied to a spray nozzle arranged to spray on the balance.
Lari was pumped in. The inlet air was heated to 575 ° F. Magnetic slurry spray speed
Adjusted to 0.3 gpm as indicated on the air flow meter. Slurry with 50 psig atomizing air pressure
Spraying system nozzle, body number 60150 and cap
Loop number 120 was used. Solid discharged from the outlet of the rotating drum is fed to the drum inlet
Returned and recirculated. The spray slurry coated the sand particles and dried at the same time.
As this process continues, a uniform off-white coating of CMA
Formed on sand particles. There was no sign of particle aggregation. A lot of bug house inspections
Very fine and light dust was shown to be collected in the baghouse hopper. Jet
As the fog continued, the CMA coating on the sand steadily increased over time. Continue spraying
, Granules with 16%, 27%, 36% and 56% CM coating
Samples consisting of offspring were withdrawn over time. Calculation of spray yield (from dust to Rather, the weight percent of CMA sprayed by the coating on sand is only 42%.
It was shown to be. (This requires very high dust recirculation in commercial methods
Waxing and production rates are significantly reduced and drying costs are low due to their low spray yield.
It would increase significantly).   The composite particles consisted of individual sand particles substantially uniformly coated with the outer shell of CMA
. When the crushing strength of the CMA shell is measured, it decreases as the CMA percentage increases.
I understood. With the highest percentage of CMA and the softest shell, the shell is usually without appreciable damage
Hard enough to withstand storage and handling. Crushing of outer shell of 56% CMA pellet
The strength was 2.8 pounds force as measured with a force gauge.   The pH of the product solution was 10.1 for 1 part of 27% CMA product mixed with 3 parts of water.
It was 2. Final product containing 56% CMA tests 60.8 pounds / cubic
Indicate the bulk density of feet.   The 36% CMA product was tested for ice melting tendency at 27 ° F. This pellet is on ice
Immediately adhered. A visible liquid forms in 5 minutes and a visible melt takes 90 minutes
Followed. 129 ml of liquid effluent with 36% CMA pellet 100 after 90 minutes of melting time
g.                                 Example 2 Production of CMA in sand deicing compositions with increased yield   The basic steps outlined in Example 1 were as follows. Large CMA during slurry spraying
Because it was clear that the parts would be dust rather than the coating on the particles
, Spray coating efficiency at various slurry temperatures (CM during spraying with substrate particles coated)
A test was performed to determine the percentage of A). To measure the amount of CMA input
Analyze slurry for water percentage combined with reading slurry tank level
Measuring the initial weight of the sand in the rotating drum,
To analyze the CMA-coated sand for the percentage of CMA present as
So we did this. Spray yield was found to depend primarily on slurry temperature
Was. Other variables such as slurry moisture, excessive unreacted lime, particle temperature and spray atomization
The number had a much smaller effect on the coating efficiency. Dolomite lime and acetic acid anti
Table I shows the results of the runs on the CMA slurries produced accordingly. This data is
fog Coating yields show much higher when slurry is heated above 155 ° F
You.   The actual method is to collect the formed dust and slurry tank with additional water
Must be recycled. Make and test all of the slurry from reslurried dust
Was performed. The coating yield for this case is also
Very dependent on temperature.   The data in Table II shows that spray coating yields are much higher for reheated slurries.
However, the slurry made by reacting lime and acid re-slurries
Not high for chemical dust. Dust type due to small change in slurry temperature
The ability to adjust the composition was surprising. Slurry appearance does not change significantly by heating
This dramatic effect on coating yield can be obtained from solubility data or
Would not be expected from previous experience with   Another beneficial effect of operating at higher slurry temperatures is higher compared to operating at lower slurry temperatures
Hardness of CMA coating increased by 50% over slurry temperature operation
Was found. During transport and storage of product due to increased hardness of CMA coating
A product was provided that was well resistant to degradation forming dust and fines. Example 3 Continuous production of CMA coated sand   CMA coating was performed by a continuous method using the same pelletizing apparatus as described in Example 1.
Sand cover was manufactured.   Sand was continuously fed to the inlet end of the rotating drum. Slurry at the front of the drum
Sprayed on a moving solid. Under the conditions used in the initial run, fix the drum from the outlet end.
These solids are continuously returned to the inlet end of the drum, resulting in a high rate of body release.
Was. A portion of the exit solids was removed frequently to keep a certain amount of solids in the drum. High solids
It is easy for coated sand particles to have a wide range of coating thicknesses under conditions of recirculation rate
I understand. Dramatically moving the drums off a portion of the new sand supply and many CMA coats
Did not receive the ringing. Another part of the sand supply has a longer residence time in the drum
And received higher coating levels. This product is less covered sand
And a mixture of larger coated sand particles, which gives the appearance of salt and pepper
I had.   An intermediate dam consisting of a tubular member having a depth of about 15% of the drum diameter
Was provided. So that most of it is available on the floor in the spray impingement zone of the drum.
The dam ensures that the particulate matter in the drum rises. The dam has a floor at the end of the run
A gate was provided that could be opened to the public.   After the above test, the gate in the dam does not seal properly, which is low rise and high
It has been found to cause a solids recycle rate. The dam is sealed and a continuous sand supply A new run was made with continuous product withdrawal. Can be operated without recirculation
It turned out to be noh. This is a product with a uniform level of CMA coating
Was found to occur. The operating conditions for this run are shown in Table III.   After 3.5 hours of operation, the product removed is sieved into fractions of different sizes and
Each fraction was then analyzed for CMA coating percentage. The results are shown in Table IV
.   The result is that most of the product is in the size range of -6 to +20 mesh
This shows that the coating level is reasonably uniform within this dimensional range.
You.   Continuous reactor operation was shown in another test run. No unusual operation problems occurred. Operation
The working conditions are summarized in Table V.   As the data in Table V shows, the lime and excess reaction resulted in a reactor and slurry tank.
There was a rise in the pH during. Example 4 Relationship between slurry pH and product pH   In the course of producing the CMA-coated sand composition by the process described in the above example,
The product pH was found to be significantly higher than the pH of the slurry from which the product was made. Slightly
A test was performed to see what the product pH was for the operation with an acidic slurry.
Was. This slightly acidic slurry reacts completely with the lime, leaving minimal insoluble material.
Is expected. A slurry having a pH of 6.3 to 6.8 has a pH of 9.8 to 10.
It was found to give a product with a pH of 0. Has a pH of 6.3 to 6.8
Table VI shows the results for operation with different slurries.   The outlet gas from the rotating drum is tested at the baghouse outlet for acetic acid and acid volatilization
It was measured whether there was. The result is between 30 and 80 by volume, depending on the slurry pH.
It showed ppm acetic acid. At slurry pH levels of 6.6 or higher, the outlet gas acetic acid
The concentration was 30 ppm. At a slurry pH level of 6.3, the outlet gas acid concentration is 80
ppm. Thus, the apparent excess acid in the slurry was volatilized;
There was some acid loss even when there was no excess acid in the slurry. However
These acid losses are determined by the measured outlet gas flow rate and 30-50 ppm in the outlet gas.
Very small based on the measured concentration of acetic acid. This weight loss is equal to the total
It was calculated to be less than 1% of acetic acid. This acid weight loss is not a significant economic factor.   Nevertheless, this increase in pH during the coating operation is sufficient due to the aforementioned acid vapor loss.
Not explained in minutes, so this is amazing. (A small amount of basic magnesium
It is possible that acetate is formed by this acid weight loss, but this is observed
It does not seem to be a sufficient explanation for the increase in pH). However, this increase in pH
Very beneficial and desirable because the least insoluble, unreacted lime is neutral or
Obtained by neutralization to a slightly acidic final slurry, but at the same time W. Schenk “Ice-Me
lting Charactertstics of Calcium Magnesium Acetate, Final Reports, Execut
ive Summary "Concrete that occurs below pH 8 in February 1985
By obtaining a product pH with a pH high enough to avoid peeling. Example 5 Production of calcium acetate coated on sand   High calcium content lime using high calcium content lime
The procedure outlined in Example 1 was followed to produce the calcium acetate. Described in Example 1
A slurry was made by the process. Charge 70 gallons of water to the reaction tank and
Hydrated lime (Genstar Lime Co., San Mateo, California, 85% Ca (OH)_Two
(Minimum) 150 pounds was added. 200 pounds of glacial acetic acid was slowly added. Acid addition
Later, the slurry became very viscous. The slurry was diluted by adding 2 gallons of water.   Convert this slurry to calcium acetate coated sand according to the process outlined in Example 1.
did. The test run conditions and results are summarized in Table VII. No operational problems occurred. La
Forty-four pounds of dust was recycled to the slurry. The results shown in Table VII are for acetate.
Sand coating method is similar to the result for calcium magnesium acetate
Shows that it produces results for calcium acetate. Slurry temperature is low, 82
94 ° F., and therefore the spray coating yield was low, 34%.
This finding, which produces low yields at low slurry temperatures, is
Consistent with the results for the Example 6 Production of high magnesium content CMA-coated sand   Referring to Table VIII, run numbers 46, 48 and similar to those described in Example 1
45, produces CMA-coated sand using the process, however, dolomite stone
A higher magnesium content was produced using a mixture of ash and magnesium oxide. Use
The magnesium oxide used was grade 20,325 type (National Magnesia Corpor
ation, Moss Landing, California). In addition, the slurry is slightly acidic
To obtain a complete lime reaction. Heat the slurry before spraying to increase spray yield
Was.   As shown in Table VIII, the pH of the final product is between 9.8 and 10.0,
The residual base level in the product was very low. This product is also
It has a high crushing strength and high product bulk density for the ringing.                                 Example 7 Production of "Neat-CMA"   Using run steps similar to Example 1, run numbers 35, 40, 47 and 44 in Table VIII
Performed, but essentially did not use sand. Solid CMA particles in a rotating drum The first material used to establish a concrete floor is to break 56% CMA coated sand
Then, crush the crushed material with a 24 mesh sieve to separate the CMA particles from the sand.
It was obtained by doing. Use -24 mesh CMA particles as starting bed
did. In commercial operation, a large product or a portion of a product
It provides small particles that can be circulated and coated by the slurry feed. Discharged from the drum
Small particles can also be removed from the material to be sieved and then ground.
Recirculate with feed.   As the data in Table VIII shows, the bulk density of the product was 38.80 cubic feet.
4 to 44 pounds, lower than for sand-coated products, but better handling
High enough as a characteristic. Runs 35 and 45 have 24 meshes that produce small size products.
A sieving product sieve was used. Runs 47 and 44 yield much larger products.
A shear 10 mesh product sieve was used. Product sieve with larger aperture
Even larger sized products can be produced by the use of a metal. Stray
The crushing strength of smart CMA pellets along with the higher slurry temperature operation (Run 40)
And improved with lower calcium to magnesium ratios (Runs 47 and 44).
The pellet abrasion test shows very good resistance to abrasion, which is
Medium dust formation was not a problem. Example 8   De-icing composition by simultaneous coating process using cement mixer
Manufacturing of   Calcium calcium is produced by a direct reaction method using a cement mixer according to the following process.
Gnesium acetate coated sand was produced.   25 pounds of sand (No. 2 sandblasting grade) into a cement mixer
I put it. The internal lifter of the mixer produced a tight curtain of sand. Squirt a pound of water
It was sprayed on sand using an atomizing nozzle. Powdered lime, S-type hydrated dolomite lime 1
. 79 pounds were added to the wet sand. Using an atomizing nozzle, glacial acetic acid 2.47 po
Was sprayed onto the sand-lime mixture. After the acid addition is completed, mix for about 30 minutes
Continued.   The compositions prepared according to the above steps are disclosed as sample numbers 1 and 2 in Table X
You.                                 Example 9   Rotary Drum Pelletizer-Calcium Magnesium Acetate Using Dryer
Production of coated sand   According to the following process, a direct reaction method using a rotary drum pelletizer-dryer is used.
Calcium magnesium acetate coated sand was produced.   Rotary drum pelletizer so that sand is recirculated from the drum outlet to the drum inlet
-Dryer was charged with 500 pounds of sand (No. 2 sandblasting grade)
. Spray water continuously on the sand in the front part of the drum before the sand reaches the lifter
did. Lime (S-type hydrated dolomite) was continuously supplied to this front part (48 points).
To India). After the wet sand and dry lime mixture are sent to the lifter section,
Acetic acid (up to 67 pounds) was sprayed onto the mixture using an air atomization spray nozzle
. A free-flowing mass of discrete particles with some acid odor was obtained.   Table X shows the compositions prepared according to the above procedures as sample nos. 3 is disclosed.                                 Example 10 Continuous production of "neat CMA"   Calcium magnesium acetate (CM) on a commercial scale by the following continuous method A) A deicing agent was produced. S-type hydrated dolomite lime about 1440 pounds / hour and oxide
Cover with about 750 pounds / hour of gnesium and stir mixed tank (reaction chain)
Water is added continuously (at a rate sufficient to maintain about 32% by weight of the CMA slurry at the outlet).
I got it. The solid acid is added to the eductor throat using water as the educting medium.
Magnesium oxide as a slurry with water, produced by pulling in magnesium oxide
Cium was added. The resulting mixture is gravity driven through a series of four additional mixing vessels.
Flowed. Overflow through trough to:   Overflow the fifth mixing tank and add about 9.6 gal / min to the reactor.
Glacial acetic acid is then added and complete high shear mixing produces an outlet pH of about 5.6. High energy
The reactor is vented through a Ruggy wet scrubber to reduce acetic acid emissions to the atmosphere.
Water is continuously blown out from this scrubber to supply water to the first mixing tank.
used. As the slurry overflows to the second reactor, excess acetic acid is
This flow was added to maintain a slurry pH of about 6.0 in the slurry tank.   The overall average formula for the CMA slurry was as follows:     0.8 pounds acetic acid / pound dry CMA     S-type lime 0.23 pounds / dry CMA pounds     0.11 pound magnesium oxide / pound CMA dry   Keeping the resulting slurry at a temperature of about 186 ° F, pumping into the spray nozzle and
The CMA pellets were sprayed onto a falling bed in front of a rotating drum. This drum has internal
A lifter, internal dam and external solids recirculation system were provided. Also fan, entrance empty
Also included are a gas heater and a baghouse dust collector on the outlet air. About 700 ° F
Introduce air at a temperature and flow rate of about 29,000 standard cubic feet per minute (SCFM)
I do. Air exited the drum at about 151 ° F and was allowed to dust before entering the atmosphere.
I entered the bug house. Approximately 1500 pounds of dust collected from this Bakuhouse
/ Hour is recirculated to the slurry tank and maintained to maintain about a 68% by weight moisture slurry.
Additional water was added.   CMA pellets formed or enlarged in a drum with a sieving system
Classified. Crush the pellets that do not pass through a 3/8 inch sieve and before the drum
Recirculated toward. Pellets passing through a 30 mesh sieve were also recycled.
. About 5% of the pellets within the 3/8 inch + 30 mesh product range are product
Withdrawal and transfer to storage and the remaining 95% is recycled to the front of the drum.   The product made from this run has a calcium / magnesium molar ratio of about 0.45.
(Ie, 3.1 to 6.9 [about 1: 2.2]), has a pH of about 9.5, and
About 1.86% by weight of a water-insoluble substance.                                 Example 10A Continuous production of "neat CMA"   Calcium magnesium acetate (C
MA) Deicing agent was produced.   S-hydrated dolomite lime at about 2120 pounds / hour and oxidation at about 990 pounds / hour
About 42% by weight of CMA slurry on exiting the reactor train with magnesium
Water was added continuously to the stirred mixing vessel at a rate sufficient to keep. The resulting mix
The object flows by gravity through the additional mixing vessel and through the trough from the first to the next.
Overflowed to   When overflowing to the second mixing vessel, about 11
. Glacial acetic acid was added at a rate of 3 gal / min, resulting in an outlet pH of about 9. Slurry is second anti
When the overflow occurs in the reactor, keep about 7.5 slurry in the slurry tank
A small stream of additional acetic acid was added to the mixture. This reactor is a high energy wet scrubber
To reduce the release of acetic acid to the atmosphere. Use this as supply water to the first mixing vessel.
Water from the scrubber was used continuously.   The overall formula for the CMA slurry was as follows:     0.79 pounds acetic acid / pound dry CMA     S-type lime 0.26 pounds / dry CMA pounds     0.12 lbs magnesium oxide / lb dry CMA   Keep the resulting slurry at a temperature of about 190 ° F (88 ° C) and pump to the spray nozzle
And sprayed onto a falling bed of CMA pellets in front of a rotating drum. This dora
The system was equipped with an internal lifter, internal dam and external solid recirculation system. Also a fan
Air system consisting of an inlet air heater and a baghouse dust collector on the outlet air
Also included. At a temperature of about 800 ° F (427 ° C) and about 32,000 standard cubic
ー Of air per minute (SCFM). Air at about 200 ° F (93 ° C)
Exited the drum and entered the baghouse to remove dust before entering the atmosphere. bug
About 500 pounds / hour of dust collected from the house is recirculated to the slurry tank and
Additional water was added to maintain a slurry of about 58% by weight moisture.   After exiting the drum, the CMA pellets formed or used in the drum are removed.
Classification was performed using a sorting system. Powder pellets larger than 6 mesh sieve
Crushed and recycled to the front of the drum. Pellet smaller than 8 mesh sieve
Was also recirculated. Approximately 5% of pellets from drums are from -6 mesh to +8 mesh
Within the product range of the product, withdrawn as product and transferred to storage, the remaining 95
% Recirculated forward of the drum.   The product produced from this orchid has about 0.46 (about 1: 2.2) calcium / ma
It has a gnesium molar ratio, a pH of about 9.5, and about 2.1% by weight of water insoluble
Substance.                                 Example 11 CMA production at low temperature   Combine lime (S-type dolomite), magnesium oxide and water in a beaker
A slurry was produced. Glacial acetic acid was added to the slurry. 1/2 hour of the resulting slurry
Heat with mixing to give a final slurry temperature of about 130-140 ° F. Slurry
PH was measured; if necessary, additional acetic acid was added to range from about 5.0 to 7.0
PH was given within. The slurry was filtered through filter paper to remove insolubles. About 95
The filtrate was dried overnight in a vacuum oven at -100 ° C to yield a low temperature CMA sample.   Samples prepared according to the above steps are disclosed in Table IX.   The X-ray pattern in FIG. 7F shows an incomplete reaction to CMA double salt at this low temperature.
Indicated.                                 Example 12 Measurement of crushing strength   C of the deicing composition using Chatilon DPP-1 force gauge (durometer)
The crush strength of the MA layer was measured. One revolution around the gauge equals 10 pounds of force.
(Segments were 0.1 lb / f increments). Force gauge the particles to be processed
Was placed in the lab jack just below the plunger / disk assembly. Should be processed
The lab jack was raised using a height adjustment screw until the particles were properly held.
The force gauge was set to zero. Pressure was applied to the particles until the CMA layer broke: force was applied at this point
read. The results are shown in Table X.                                 Example 13 Measurement of wear resistance   Using ASTM D4058-81 to measure the attrition resistance of the CMA deicing composition
Was.   The results for various CMA compositions, reported in percentage weight loss for attrition, are listed below. Displayed in Table X. Example 14 Emission gas analysis by TGA-GC-MSD   Direct reaction and slurry method using outgassing analysis by TGA-GC-MSD (
CMAs produced according to both Examples 1 to 9) were compared. This technology has spread over time
Withdrawing outgassing from a standard thermogravimetric analyzer (TGA) as it is manufactured
This gas was subjected to capillary gas chromatography (GC). Mass selection detector (M
The gas was analyzed at the end of the GC column using SD). Some preset mass
Monitored the total ion count over time. Typical analysis performed in about 50 minutes
became.   The TGA used was DuPont 951 TGA, which was
Set to be controlled by computer. GC-MSD is 5970 Quadra
Hewlett Packard 5890 AGC with a pull MSD. This GC is 1
A 5 or 50 meter SC-32 capillary column was used (cross-linked methyl silicon
, Film thickness 0.33 microns, inner diameter 0.30 microns). G at TGA exit
Connected to C injector. GC inlet system set at 100: 1 split ratio
. All transfer lines between the TGA and GC injector were wrapped with heating tape.   The GC-MSD continuously monitored the TGA outgassing.   Monitor outgassing at mass 18 (water) to detect unreacted magnesium base.
I did. At a temperature of about 300 ° C. by TGA or after about 14 to 16 minutes,
Reaction of magnesium hydroxide (or hydrated magnesium oxide) to calcium was observed
. The lower limit of detection of unreacted magnesium base by the above method was about 1%.
.   A sample of CMA produced by the direct reaction method (Examples 8 and 9) was unreacted magnesium
It showed about 5% (of CMA) as base.   Samples of CMA produced by the slurry process method (Examples 1 to 7) are essentially detectable
No magnesium base.                                 Example 15 Analysis of CA, MA and CMA by TGA-GC-MSD analysis   Emission gas analysis by TGA-GC-MSD using CA and MA standards and direct
CMA samples produced by both the contact reaction method and the slurry method were compared. When this technology Gas emitted from a standard thermogravimetric analyzer (TGA)
The gas was removed and subjected to low resolution gas chromatography (GC). mass
The gas was recorded at the end of the GC column using a selective detector (MSD). Presset
The total ion count can be monitored over time by mass.   The TGA-GC-MSD device used was described in Example 14.   Unless otherwise specified, use a heating rate of 10 ° C / min and use a helium carrier gas.
Lever TGA-GC-MSD analysis was performed. Helium flow rate set to 80cc / min
I did it. The GC-MSD chromatogram was plotted as a function of time. TGA
The starting temperature was kept at 25 ° C.   Monitor the relative ionic abundance by the molecular weight of acetone, carbon dioxide and water and
Plotted over time. In addition, a graph showing total ion count (TIC) versus time.
The spectra are also plotted. For some plots, the two plots are identical
2.5 to match the scale of acetone abundance as superimposed in the figure
Carbon dioxide abundance was reduced by a factor of three.   CA hemihydrate and MA tetrahydrate standard were purchased from J.I. T. Purchased from Baker. 1: 1 ratio
Produced a CA-MA mixture by mixing CA and MA. Examples 1 to 1
Other CMA preparations were made by processes such as those described in OA. TGA-
The samples used for GC-MSD analysis are listed in Table XI.   Monitor outgassing with masses corresponding to acetone and carbon dioxide and time relationships
Plotted as   The TGA-GC-MSD chromatograph shown in FIGS. 5A to 5C and FIGS. 6A to 6C.
The matogram is a gas with a mass corresponding to acetone and carbon dioxide as a function of time.
Plot out.   8A to 8D, 9A to 9D, 10A to 10D, 11A to
TGA-GC-MSD chromatogram shown in FIG. 11D and FIGS. 12A to 12D.
The ram gas is released as a function of time with masses corresponding to water, acetone and carbon dioxide.
Output and total ion content are plotted. Example 16 X-ray diffraction analysis   Crystalline calcium acetate hemihydrate, crystalline magnesium acetate hemihydrate
X-ray diffraction analysis of crystalline, crystalline magnesium acetate tetrahydrate and various CMA samples
Done.   X-ray diffraction peaks of crystalline CA are superimposed on FIGS. 7A, 7C, 7D, 7E and 7F.
Assisted in locating any crystalline CA impurities. X-ray of CMA double salt
The diffraction patterns are summarized in Table XIII. 2θ peak position in degrees; d interval and relative intensity
Indicates the degree.   This analysis was performed using a Siemens D500 diffractometer equipped with copper tubes (so
The 2θ values shown in FIGS. 7A-7F are for Cu Ka radiation). Peak position
Use the Siemens DIFFRAC 11 software package for installation
Was.   The samples used for X-ray diffraction studies are shown in Table XII.   7A to 7F show the X-ray diffraction patterns for the samples shown in Table XII.

Claims (1)

[Claims] 1. Up to 8% by weight of crystalline calcium acetate, up to 8% by weight of magnesium acetate , up to 3% by weight of unreacted magnesium base and up to 5% by weight of water
A deicing composition comprising substantially pure calcium magnesium acetate double salt containing or not containing. 2. 5 wt% or less of crystalline calcium acetate, deicing composition according to claim 1, wherein containing 5 wt% or less of magnesium acetate and 1 wt% or less of unreacted magnesium base. 3. 3. The deicing composition according to claim 2, comprising not more than 2.5% by weight of water. 4. 6A, 8A to 8D or 9A to 9D, substantially the same TGA-GC-
3. The deicing composition according to claim 1 or 2, which exhibits an MSD spectrum and an X-ray diffraction pattern substantially identical to those of Figs. 7C, 7D or 7G. 5. Claim 1 having a calcium: magnesium ratio of 4: 6 to 3: 7.
Deicing composition according to paragraph or 2 . 6. Claim 5 having a calcium: magnesium ratio of 3: 6 to 3: 7.
Deicing composition according to paragraph. 7. TGA-GC-MSD substantially identical to Figures 8A to 8D or 9A to 9D
And an X-ray diffraction pattern that is substantially the same as 7C, 7D or 7G.
Deicing composition according to clause 6 . 8. Claim 1 having the empirical formula: Ca _x Mg _y (C ₂ H ₃ O ₂ ) ₂ (x + y), wherein x is 3 to 4 and y is 7 to 6.
Deicing composition according to paragraph or 2 . 9. TGA-GC-M substantially identical to 6A, 8A to 8D or 9A to 9D
9. The deicing composition according to claim 8, which exhibits an SD spectrum and an X-ray diffraction pattern substantially identical to those of FIGS. 10 ． 9. The deicing composition according to claim 8, comprising not more than 2.5% by weight of water. 11 ． 9. The deicing according to claim 8, which exhibits a TGA-GC-MSD spectrum substantially identical to FIGS. 6A, 8A to 8D or 9A to 9D and an X-ray diffraction pattern substantially identical to FIGS. Composition. 12 ． A deicing composition comprising a plurality of layers of the composition according to claim 8 on discontinuous substrate particles. 13 ． 13. The deicing composition according to claim 12, wherein said base particles comprise a friction aid. 14 ． 13. The deicing composition according to claim 12, wherein said base particles include particles of a calcium magnesium acetate double salt. 15 ． 9. A deicing composition comprising a composition according to claim 8 having a bulk density of at least 40 pounds / cubic foot, a particle specific gravity greater than 1.2, and an attrition of less than 3%. 16 ． A pelletized deicing composition comprising a composition according to claim 8 having a bulk density of at least 40 pounds / cubic foot, a particle specific gravity greater than 1.2, and an attrition of less than 3%. 17 ． A process for preparing a deicing composition comprising crystalline calcium acetate, magnesium acetate and a calcium magnesium acetate double salt substantially free of unreacted magnesium base, comprising: (a) containing at least 40% by weight of water, from 4: 6 to 3; : Calcium of 7:
Preparing an aqueous mixture of CM base having a magnesium ratio; (b) 70-110% of the stoichiometric amount of acetic acid required to convert said CM base to said double salt and step (a) And mixing the resulting mixture to at least 5
Producing a CMA slurry containing 0% by weight of water; (c) if necessary, the total amount of acetic acid is approximately the stoichiometric amount of acetic acid required to convert the CM base to the double salt. Adding sufficient acetic acid to the slurry to be in an amount; and (d) aging the CM slurry to effect a substantially complete reaction of the acetic acid with the CM base. Recipe. 18 ． 18. The method according to claim 17 , further comprising: (e) drying and pelletizing the slurry of step (d) to produce a dry, free-flowing product. 19 . Wherein the drying and pelletizing of step (e) comprises distributing the slurry of step (d) into a thin layer on the discontinuous substrate particles and drying the substrate particles. The method according to clause 18, 20 . Claims: In step (e), the slurry of step (d) is distributed in a thin layer on a falling curtain of discontinuous substrate particles in the presence of the heated gas to produce stratified particles.
Method according to clause 19 . 21 . 21. The method according to claim 20 , further comprising: (f) repeating step (e) to produce a layered particle having a plurality of layers on said particle. 22 . 18. The method according to claim 17 , wherein step (b) further comprises mixing the mixture of step (a) with said amount of acetic acid. 23 . Step (c) measures the pH of the slurry of step (b), and optionally,
22. The method of claim 22 , further comprising adding sufficient acetic acid to produce a pH of 7 to 8.5.
By term. 24 . 18. The method according to claim 17 , wherein step (d) is performed at a temperature of at least 150 ° F. 25 . 18. The method according to claim 17 , wherein step (d) is performed at a temperature between 170 and 200 ° F. 26 . 26. The method according to claim 25 , wherein the CMA slurry contains 55 to 68% by weight water. 27 . 26. The method according to claim 25 , wherein step (b) further comprises mixing a stoichiometric amount of 90% by weight acetic acid. 28 . 28. The method according to claim 27, wherein step (d) comprises aging said slurry for at least 3.5 hours. 29 . In the preparation of a deicing composition comprising a calcium magnesium acetate double salt substantially free of crystalline calcium acetate, magnesium acetate and unreacted magnesium base and substantially anhydrous; (a) containing at least 40% by weight of water And preparing an aqueous mixture of the CM base having a calcium: magnesium ratio of 4: 6 to 3: 7; (b) the stoichiometric amount required to convert the CM base to the double salt Simultaneously mixing the mixture of step (a) with 90% of the acetic acid;
Producing a CMA slurry containing 0% by weight of water; (c) adding, if necessary, additional acetic acid to produce a pH of 7 to 8.5; (d) aging the CM slurry to obtain acetic acid. Effecting substantially complete reaction of the CM with the CM base; and (e) drying and pelletizing the slurry of step (d) to yield a dry, free-flowing product. Recipe. 30 . 30. The method according to claim 29 , wherein step (d) is performed at a temperature of at least 150F. 31 . 30. The method according to claim 29 , wherein step (d) is performed at a temperature between 170 and 200 ° F. 32 . Wherein the drying and pelletizing of step (e) comprises distributing the slurry of step (d) in a thin layer over the discontinuous substrate particles and drying the substrate particles. The method according to paragraph 30 . 33 . 32. The method according to claim 32 , wherein said distributing in step (e) is performed without excess atomizing air.
By term. 34 . It is substantially free of crystalline calcium acetate, magnesium acetate and unreacted magnesium base, and has an empirical formula: Ca _x Mg _y (C ₂ H ₃ O ₂ ) ₂ (x + y) (where x is 3 to 4) And y is from 7 to 6). In a process for preparing a deicing composition comprising a calcium magnesium double salt having: (a) an aqueous flowable mixture of a CM base having a calcium: magnesium ratio of 4: 6 to 3: 7; (B) admixing the mixture of step (a) with 70-110% of the stoichiometric amount of acetic acid required to convert the CM base to the double salt to form a CMA slurry That the slurry is fluid and contains enough water to be pumpable; (c) If necessary, the total amount of acetic acid added will convert approximately the CM salt to the double salt. The stoichiometric amount of acetic acid required for By adding a sufficient additional acetic acid to the slurry; and (d) CM slurry is left to age by possible to perform a substantially complete reaction of acetic acid and CM base, method of the deicing composition comprising a. 35 . 35. The method according to claim 34 , further comprising the step (e) of drying and pelletizing the slurry of step (d) to produce a dry, free flowing product that is substantially anhydrous. 36 . A process for preparing a deicing composition comprising crystalline calcium acetate, magnesium acetate and a calcium magnesium acetate double salt substantially free of unreacted magnesium base; (a ') containing at least 40% by weight of water, 4: 6 From 3: 7 calcium:
Preparing an aqueous mixture of CM base having a magnesium ratio; (b ') the stoichiometric amount of 70 required to convert said CM base to said double salt;
To 110% of acetic acid and the mixture of step (a '), and if necessary, the total amount of acetic acid is approximately the stoichiometric amount required to convert the CM base to the double salt. Adding sufficient additional acetic acid to said slurry such that a substantially complete reaction takes place such that: 37 . 37. The method according to claim 36 , further comprising drying and pelletizing the slurry of step (b) to produce a dry, free flowing product that is substantially anhydrous.