APPENDIX A. SELECTED CHEMICALS and THEIR PROPERTIES
Information is presented in this postposition on the nature of five chemicals used for anti-icing treatments and also instructions because that preparing various liquid concentrations. The five chemicals room calcium chloride, salt chloride, magnesium chloride, calcium magnesium acetate, and also potassium acetate. Lock are detailed here through their eutectic temperatures and also concentrations:
|calcium chloride (CaCl2)||-51 (-60)||29.8|
|sodium chloride (NaCl)||-21 (-5.8)||23.3|
|magnesium chloride (MgCl2)||-33 (-28)||21.6|
|calcium magnesium acetate (CMA)||-27.5 (-17.5)||32.5|
|potassium acetate (KAc)||-60 (-76)||49|
No details is noted on the corrosive properties or environmental facets of the chemicals. Discussions of these items have the right to be found in the literature. Similarly no expense data for the chemicals are given. These data have the right to be acquired readily from distributors.
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A.1 CALCIUM CHLORIDE, CaCl2
Two approaches are used to manufacture advertisement CaCl2: exploit from organic brines acquired from deep wells, principally in Michigan; and by a chemistry process, the Solvay process, in which salt chloride is reacted with calcium carbonate to produce sodium lead carbonate (soda ash) and also calcium chloride.
The American society for Testing and also Materials (ASTM) has actually prepared two standards for calcium chloride: D 98 Specification because that Calcium Chloride, and E 449 Standard Test method of evaluation of Calcium Chloride.
A.1.2 ready of fluid CaCl2
Solid calcium chloride dissolves easily in water with tiny agitation required. Significant heat is given off when it dissolves. Two techniques of mixing have the right to be provided to obtain a specific concentration of fluid CaCl2. An approach 1 is used if the volume that the mixing container is known. Use method 2 if the volume that the mixing container is no known. Each of these approaches is defined below. For both, the water temperature have to be listed below 20°C (68°F).
A.1.2.1 method 1 (Known mixing container volume)native the “per volume solution” column of Table 2 identify the weight in kg (or lb) of heavy calcium chloride forced to make 1 m3 (or 1 gal) of systems at the desired concentration level. This value, multiply by the volume of the container in m3 (or gal), offers the complete weight the calcium chloride required.Fill the container roughly 2/3 complete of water, then include the compelled calcium chloride slowly while stirring carefully with a paddle by hand, v a mechanical agitator, or v an air bubbler. After the calcium chloride has completely dissolved, include water to the container to bring the level to the working volume and also then agitate the solution gradually until a uniform mixture is obtained.
|10||139 (1.16)||146 (1.22)||-5.4 (22.3)||1085 (9.06)|
|15||218 (1.82)||238 (1.99)||-10.3 (13.5)||1133 (9.46)|
|20||303 (2.53)||344 (2.87)||-18.0 (-0.4)||1185 (9.89)|
|25||397 (3.31)||471 (3.93)||-29.4 (-21)||1234 (10.3)|
|29.8*||491 (4.1)||621 (5.18)||-55.0 (-67)||1288 (10.75)|
|30||498 (4.16)||627 (5.23)||-46.0 (-50.8)||1294 (10.8)|
*Note: this is the "eutectic" point, i.e., the concentration that outcomes in the lowest temperature (-55°C (-67°F)) at which a solution can exist while remaining completely liquid.
A.1.2.2 an approach 2 (Unknown mixing container volume)placed a measured volume that water in the container to no more than 2/3 of the container capacity.Dissolve in it the required weight of calcium chloride given in the "per volume water" column of Table 2 for each cubic meter (or gallon) of water used. Include the calcium chloride progressively to the water through agitation.When fully dissolved, the solution will have actually the desired concentration.
A.1.2.3. Additional comments
For those mathematically inclined, the adhering to formula deserve to be provided to determine the volume the water required for a offered level of concentration.
|m3 of water forced to do a systems of a preferred concentration||=||kg dried CaCl2 x %CaCl2desired % solution||- kg dry CaCl2||÷ 1000 kg/m3 water|
Example: to make a 20 percent solution from 500 kg of flake CaCl2 (this is commonly 78 percent concentration),
|500 x 7820||- 500||÷ 1000 = 1.45 m3 water|
(In English units:
|gal of water required to do a equipment of a wanted concentration||=||lb dried CaCl2 x %CaCl2desired % solution|| lb dried CaCl2||÷ 8.34 lb/gal water|
Example: to make a 20 percent solution from 1000 lb the flake CaCl2 (this is typically 78 percent concentration),
|1000 x 7820||- 1000||÷ 8.34 = 348 gal water|
A indigenous of caution. Calcium chloride when liquified gives off heat. This heat of solution causes the brine come expand and also occupy more space than it will certainly after the cools. That’s why the container in method 2 is filled come no an ext than 2/3 capacity. Because that example, additional tank volume of roughly 90 l (23 gal) for every
4 m3 (1000 gal) the 20 percent systems is required. This will boost slightly come 100 together (26 gal) because that every 4 m3 (1000 gal) of a 34 percent solution.
Always add the calcium chloride to the water. If you put the calcium chloride in the container an initial and then include water, the chemical may kind a solid massive which is an overwhelming to dissolve completely.
A.2 salt CHLORIDE, NaCl
A.2.1 heavy NaCl
Sodium chloride has actually been provided as one ice-control chemistry on roads because early in this century. It is developed by three processes: rock salt is mined by conventional hard rock mining equipment and also techniques; solar salt is developed by the evaporation that sea water and may contain only a little amount of impurities; and evaporated or solution or vacuum salt, a really pure type made by dry under vacuum the solution resulting native injection of water right into deep secret deposits. Most salt provided for highway applications in the United claims is absent salt, though some solar salt is created in number of western states and some is imported right into the east US. Naturally arising rock salt is the mineral halite, and also usually contains between 1 percent and 4 percent impurities, greatly gypsum, shale, dolomite, and quartz.
The ASTM designation for salt offered for highway ice manage is D 632 Standard Specification for sodium Chloride.
Two gradations the salt room designated by the ASTM typical as presented in Table 3. Similar but slightly different gradations are offered by the British. These together with the Swedish and Finnish gradations are displayed below, in Tables 4, 5 and also 6, respectively.
|19.0 mm (3/4 in) 12.5 mm (1/2 in) 9.5 mm (3/8 in) 4.75 mm (No. 4) 2.36 mm (No. 8) 600 µm (No. 30)||.... 100 95 come 100 20 to 90 10 come 60 0 come 15||100 ... ... 20 come 100 10 come 60 0 come 15|
Note: grade 1 is the most generally used gradation in the U.S.
|Rock salt||Coarse||10 mm 6.3 mm 2.36 mm 300 μm||100 75 to 95 30 come 70 0 to 20|
|Fine||6.3 mm 2.36 mm 300 μm||100 30 come 80 0 come 20|
|Vacuum salt and marine salt||Coarse||10 mm 1.18 mm 150 μm||100 0 come 80 0 to 10|
|Fine||1.18 mm 150 μm||100 0 to 30|
Table 5. Swedish gradation because that salt.
|3 2 1 0.5 0.16||95-100 65-100 26-50 5-26 0-5|
Table 6. Finnish gradation for salt.
|5 4 3 2 1 0.5||100 90-100 70-100 40-90 15-55 3-25|
A.2.2 preparation of fluid NaCl
Two methods of mixing deserve to be offered to acquire a specific concentration of liquid NaCl. An approach 1 is used if the volume the the mixing container is known and also a wanted volume the salt brine is to it is in produced. Use method 2 if the volume of the mixing container is no known. Every of these techniques is described below.
A.2.2.1 an approach 1 (Known mix container volume)indigenous the “per volume solution” column of Table 7, recognize the identify the weight in kg (or lb) of dried salt required to do 1 m3 (or 1 gal) of systems at the preferred concentration level. This value, multiplied by the volume the the container, provides the complete weight of dried salt required.Fill the container approximately 2/3 full of water, then include the required dry salt progressively while stirring through a paddle by hand, with a mechanical agitator, or with an wait bubbler.After the salt has dissolved, include water come the container to carry the level come the functioning volume and also then agitate the solution slowly until a uniform mixture is obtained. Some insoluble precipitate indigenous the impurities will continue to be in the bottom the the tank until physically removed.Finally, the salt brine should be tested through a hydrometer to recognize the percent of concentration that has been produced. Because that anti-icing operations, the concentration that the salt brine need to be as close to 23.3 percent as possible, however no much more than 25 percent. If the concentration is more than 25 percent, part water have to be added to the mixture to minimize the concentration to the wanted level. If the concentration is less than 23 percent some salt have to be included to the mixture to raise the concentration come the preferred level. The table the hydrometer readings versus percent concentration of salt offered in ar 188.8.131.52 can be offered for these tests.
|10||108 (0.9)||96 (0.8)||-6.7 (20)||1072 (8.95)|
|15||168 (1.4)||156 (1.3)||-11.1 (12)||1112 (9.28)|
|20||228 (1.9)||204 (1.7)||-17.8 (0)||1150 (9.6)|
|23*||276 (2.3)||228 (1.9)||-21.1 (-6)||1169 (9.76)|
|25||300 (2.5)||252 (2.1)||-8.9 (16)||1234 (10.3)|
*Note. This is the almost right eutectic ingredient (see explanation in calcium chloride entry above).
A.2.2.2 an approach 2 (Unknown mixing container volume)fill a hopper tank v dry salt and let water slowly run through the salt by gravity activity to the bottom the the tank. Discharge the brine at the bottom of the hopper tank right into a holding tank listed below the hopper tank. Pump the brine from the stop tank into a bigger storage tank. Stir the mixture in the bigger storage tank v a mechanical agitator or v an waiting bubbler. Proceed to add salt and also water to the hopper tank until the big storage tank is almost full. Recognize the percentage of concentration that the salt brine using a hydrometer and the table in ar 184.108.40.206. An approach 2 will create up come a 100 percent saturation brine solution depending on the rate of water circulation through the salt. A 100 percent saturated brine solution synchronizes to a 27 percent concentration level. Water have to be added now come the warehouse tank to alleviate the concentration of the mixture to the 23 to 25 percent level. Finally, the required variety of pounds the salt offered in method 2 have the right to be approximately calculated by multiplying the total volume the water by the load of salt chloride every volume the water offered in the “per volume water” pillar of Table 7 that coincides to the percent concentration level achieved. This calculation of the quantity of salt used deserve to be provided to generate succeeding volumes that mixture to to fill the warehouse tank when it is totally empty.
A.2.2.3 added comments
Method 2 above has to be used properly by several states to create a salt brine because that anti-icing operations. In practice, the brine generation process operates continuously throughout a storm. This is due to the fact that liquid brine is attracted from the warehouse tank transparent the storm to to fill the tanks ~ above the spreader vehicles. In this situation, it is necessary to commonly monitor the percentage concentration level that the mixture in the storage tank. Adjustments must be made come mixture when vital to achieve the wanted level that concentration.
A.3 MAGNESIUM CHLORIDE, MgCl2
The principal source of this ice manage chemical is brines from great Salt Lake. Though it is available in hard (flake) form, the is provided in liquid kind for ice cream control. Eutectic temperature is about -33°C (-28°F) in ~ a concentration that 21.6 percent. Its ice cream melting volume is about 40 percent higher than CaCl2. Proprietary mixtures are easily accessible containing 20 come 25 percent MgCl2 with miscellaneous corrosion inhibitor additives. One proprietary compound reportedly has an eutectic temperature of -20°C (-4°F). These options are efficient ice-melting agents in ~ temperatures above -7°C (19°F).
A.4 CALCIUM MAGNESIUM ACETATE,
Currently over there is only one commercial resource for CMA, using the reaction that acetic acid v dolomitic limestone for production. The acetic acid, the i have lot of money component of the compound, is made from herbal gas or petroleum, though little quantities have been developed by biodegradation of agricultural wastes. The compound is obtainable as pellets. Though no as dissolve in water together NaCl and CaCl2, solutions can be made at allude of usage for usage as a prewetting agent or right chemical application. That is not a highly effective deicing chemical in solid kind because that its affinity for water and also its light bit mass. Its advantage is that snow is make mealy and also will not compact. CMA is primarily a mixture of calcium and also magnesium acetates, produced with a 3/7 Ca/Mg proportion which was found to be optimum in ahead smashville247.net studies. The eutectic temperature is around -28°C (-18°F) at a concentration of 32.5 percent.
A.4.2 preparation of liquid CMA
Liquid CMA is all set by dissolving pelletized CMA in water. This procedure results in a murky equipment that settles gradually to produce a clear liquid CMA on top and also discardable insolubles on the bottom. A 25 percent concentration of fluid CMA is recommended for anti-icing operations. Specifically, of liquid CMA production are given in ar 220.127.116.11.
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A.5 POTASSIUM ACETATE, KC2H3O2
Potassium acetate, or KAc together it is typically known, is developed by the reaction the acetic acid v potassium carbonate. The resources of acetic acid are the same as are offered in the manufacturing of CMA. Potassium carbonate is just one of the group of salts commercially well-known as potash. Potassium lead carbonate was originally acquired by to run water through wood ashes and boiling the resulting systems in large iron pots. The substance that created was referred to as potash. Potassium lead carbonate is at this time produced by among several procedures that use potassium chloride, one more salt the the potash family. The compound, potassium acetate, is a white, crystalline, deliquescent flour that has actually a saline taste. It is dissolve in water and alcohol. Solutions are alkaline under a litmus test. The dry link is combustible yet is provided as a dehydrating agent, a reagent in analysis chemistry, and in the manufacturing of man-made flavors, in enhancement to various other uses. The eutectic temperature that a KAc and also water equipment is -60°C (-76°F) in ~ a concentration that 49 percent. A commercial type of liquid KAc, comprise a 50 percent concentration by load plus corrosion inhibitors, has actually been offered as a prewetting agent with dry salt or as a straight chemical application. Some experience has been acquired with the directly liquid form during anti-icing experiment (1).