Method for preparing organic environment friendly snow-melting agent by using salt mud from two-alkali method

Abstract

Disclosed is a method for preparing an organic environment-friendly snow-melting agent by using salt mud from a two-alkali method, relates to the field of environmental protection and resource utilization of solid wastes. The method includes the following steps: first, stirring and reacting an organic acid and the salt mud from a two-alkali method at room temperature to obtain a slurry; filtering the slurry to obtain a filtrate; the filtrate is then concentrated and dried by centrifugal spray drying to obtain a solid powder; granulating the solid powder. The method not only realizes the recycling of salt mud solid waste, but also greatly reduces the production cost of organic environment-friendly snow melting agent by turning waste into wealth, moreover, due to the existence of trace ions, the ability of melting snow and ice has obvious synergistic effect.

Claims

1. A method for preparing an organic environment-friendly snow-melting agent by using a salt mud from a two-alkali method, comprising: reacting the salt mud with an organic acid to obtain a slurry; filtering the slurry to obtain a filtrate; wherein the filtrate is then concentrated, dried by centrifugal spray drying, and granulated in sequence to obtain the organic environment-friendly snow-melting agent and wherein the method comprises following specific steps: (1) stirring and reacting the organic acid and the salt mud at room temperature to obtain the slurry; (2) filtering the slurry obtained in step (1) to obtain the filtrate, the filtrate is then concentrated under reduced pressure and dried by centrifugal spray drying to obtain a solid powder; (3) granulating the solid powder obtained in step (2) to obtain the organic environment-friendly snow-melting agent; a composition of the salt mud in step (1) is calculated based on weight parts: 85-95 weight parts of CaCO.sub.3, 0.5-1.5 weight parts of NaCl, 8.5-13.2 weight parts of Mg(OH).sub.2, 1.5-4.0 weight parts of CaSO.sub.4, 0.5-1.5 weight parts of Fe(OH).sub.3, 0.5-1.0 weight parts of Al(OH).sub.3 and 0.1-2.0 weight parts of SiO.sub.2.

2. The method for preparing the organic environment-friendly snow-melting agent according to claim 1, wherein the organic acid in step (1) is selected from one of formic acid, acetic acid, propionic acid or pyroligneous acid.

3. The method for preparing the organic environment-friendly snow-melting agent according to claim 1, wherein a specific operation in step (1) is to disperse the salt mud into the slurry in water, and then add the organic acid to the slurry under stirring until no bubbles appear in the slurry.

4. The method for preparing the organic environment-friendly snow-melting agent according to claim 1, wherein a particle size of the salt mud in step (1) is in a range of 30-85 m.

5. The method for preparing the organic environment-friendly snow-melting agent according to claim 1, wherein when concentrated under reduced pressure, a vacuum degree is in a range of 0.06-0.09 MPa and a temperature is in a range of 70-80 C.

6. The method for preparing the organic environment-friendly snow-melting agent according to claim 1, wherein the solid powder is subjected to roller granulation in step (3) to obtain the organic environment-friendly snow-melting agent in a particle size of 4-7 mm and a shape of ellipsoidal.

Description

DETAILED DESCRIPTION

Embodiment 1

(1) The composition of the salt mud from the two-alkali method is calculated based on weight parts: 94.5 weight parts CaCO.sub.3, 1.2 weight parts of NaCl, 29.5 weight parts of Mg(OH).sub.2, 2.5 weight parts of CaSO.sub.4, 0.7 weight parts of Fe(OH).sub.3, 0.9 weight parts of Al(OH).sub.3 and 2.0 weight parts of SiO.sub.2.

(2) (1) Stirring and dispersing the above salt mud containing 500 g CaCO.sub.3 in 500 mL of water at room temperature (25 C.) into a slurry, and then adding pure acetic acid to the slurry under stirring until no bubbles appeared in the slurry.

(3) (2) Filtering the slurry obtained in step (1) to obtain the filtrate, the filtrate was then concentrated under reduced pressure at 0.06 MPa and 75 C., and dried by centrifugal spray drying to obtain the solid powder.

(4) (3) Roller granulating the solid powder to obtain the organic environment-friendly snow-melting agent in a particle size of 4-6 mm and a shape of ellipsoidal.

Embodiment 2

(5) The composition of the salt mud is calculated based on weight parts: 93 weight parts of CaCO.sub.3, 0.8 weight parts of NaCl, 10 weight parts of Mg(OH).sub.2, 3.2 weight parts of CaSO.sub.4, 0.85 weight parts of Fe(OH).sub.3, 0.8 weight parts of Al(OH).sub.3, 0.5 weight parts of SiO.sub.2.

(6) (1) Stirring and dispersing the above salt mud containing 500 g CaCO.sub.3 in 500 mL of water at room temperature (25 C.) into a slurry and then adding pure formic acid to the slurry under stirring until no bubbles appeared in the slurry.

(7) (2) Filtering the slurry obtained in step (1) to obtain the filtrate, the filtrate was then concentrated under reduced pressure at 0.07 MPa and 80 C., and dried by centrifugal spray drying to obtain the solid powder.

(8) (3) Roller granulating the solid powder obtained in step (2) to obtain the organic environment-friendly snow-melting agent in a particle size of 4-6 mm and a shape of ellipsoidal.

Comparative Embodiment 1

(9) The amounts of CaCO.sub.3, NaCl, Mg(OH).sub.2, CaSO.sub.4, and SiO.sub.2 in the salt mud were added as the amounts of Embodiment 1 in pure form.

(10) (1) Stirring and dispersing the mixture containing 500 g CaCO.sub.3 and the composition based on weight parts of 94.5 weight parts of CaCO.sub.3, 1.2 weight parts of NaCl, 9.5 weight parts of Mg(OH).sub.2, 2.5 weight parts of CaSO.sub.4, 2.0 weight parts of SiO.sub.2 in 500 mL of water at room temperature (25 C.) into a slurry, and then adding pure acetic acid to the slurry under stirring until no bubbles appeared in the slurry.

(11) (2) Filtering the slurry obtained in step (1) to obtain the filtrate, the filtrate was then concentrated under reduced pressure at 0.06 MPa and 75 C., and dried by centrifugal spray drying to obtain the solid powder.

(12) (3) Roller granulating the solid powder obtained in step (2) to obtain the organic environment-friendly snow-melting agent in a particle size of 4-6 mm and a shape of ellipsoidal.

Comparative Embodiment 2

(13) The amounts of CaCO.sub.3, NaCl, Mg(OH).sub.2, CaSO.sub.4, and SiO.sub.2 in the salt mud were added as the amounts of Embodiment 2 in pure form:

(14) (1) Stirring and dispersing the mixture containing 500 g CaCO.sub.3 and the composition based on weight parts of 93 weight parts of CaCO.sub.3, 0.8 weight parts of NaCl, 10 weight parts of Mg(OH).sub.2, 3.2 weight parts of CaSO.sub.4, 0.85 weight parts of Fe(OH).sub.3, 0.5 weight parts of SiO.sub.2 in 500 mL of water at room temperature (25 C.) into a slurry, and then adding pure formic acid to the slurry under stirring until no bubbles appeared in the slurry.

(15) (2) Filtering the slurry obtained in step (1) to obtain the filtrate, the filtrate was then concentrated under reduced pressure at 0.07 MPa and 80 C., and dried by centrifugal spray drying to obtain the solid powder.

(16) (3) Roller granulating the solid powder obtained in step (2) to obtain the organic environment-friendly snow-melting agent in a particle size of 4-6 mm and a shape of ellipsoidal.

Comparative Embodiment 3

(17) On the basis of Embodiment 1, adding the content of Fe(OH).sub.3 and the content of Al(OH).sub.3, the composition of the salt mud is calculated based on weight parts of 94.5 weight parts of CaCO.sub.3, 1.3 weight parts of NaCl, 9.5 weight parts of Mg(OH).sub.2, 2.5 weight parts of CaSO.sub.4, 5 weight parts of Fe(OH).sub.3, 4 weight parts of Al(OH).sub.3, 2.0 weight parts of SiO.sub.2.

(18) (1) Stirring and dispersing the above salt mud containing 500 g CaCO.sub.3 in 500 mL of water at room temperature (25 C.) into a slurry, and then adding pure acetic acid to the slurry under stirring until no bubbles appeared in the slurry.

(19) (2) Filtering the slurry obtained in step (1) to obtain the filtrate, the filtrate was then concentrated under reduced pressure at 0.06 MPa and 75 C., and dried by centrifugal spray drying to obtain the solid powder.

(20) (3) Roller granulating the solid powder obtained in step (2) to obtain the organic environment-friendly snow-melting agent in a particle size of 4-6 mm and a shape of ellipsoidal.

Comparative Embodiment 4

(21) The amounts of CaCO.sub.3, NaCl, Mg(OH).sub.2, CaSO.sub.4, Al(OH).sub.3 and SiO.sub.2 in the salt mud were added as the amounts of Embodiment 2 in pure form:

(22) (1) Stirring and dispersing the mixture containing 500 g CaCO.sub.3 and the composition based on weight parts of 93 weight parts of CaCO.sub.3, 0.8 weight parts of NaCl, 10 weight parts of Mg(OH).sub.2, 3.2 weight parts of CaSO.sub.4, 0.8 weight parts of Al(OH).sub.3, 0.5 weight parts of SiO.sub.2 in 500 mL of water at room temperature (25 C.) into a slurry, and then adding pure formic acid to the slurry with stirring until no bubbles appeared in the slurry.

(23) (2) Filtering the slurry obtained in step (1) to obtain the filtrate, the filtrate was then concentrated under reduced pressure at 0.07 MPa and 80 C., and dried by centrifugal spray drying to obtain the solid powder.

(24) (3) Roller granulating the solid powder obtained in step (2) to obtain the organic environment-friendly snow-melting agent in a particle size of 4-6 mm and a shape of ellipsoidal.

(25) Test Experiment 1

(26) Corroding metal carbon steel by organic environment-friendly snow-melting agent:

(27) First, the corrosion solutions were prepared, the sodium chloride (purity99.9%) and the organic environment-friendly snow-melting agent in embodiment 1, embodiment 2, comparative embodiment 1, comparative embodiment 2, comparative embodiment 3, and comparative embodiment 4 were added to seven 2000 mL beakers respectively, then water was added to prepare test solutions of a solute mass fraction of 18.0%.

(28) The samples were rectangular carbon steel sheets NO. 20 (GB/T699) in the size of 5 mm2.5 mm0.2 mm, before the test, the surface oil of the samples was wiped off with filter paper, then the samples were dried after soaking in acetone and anhydrous ethanol, and finally wrapped in filter paper respectively and placed in a desiccator for later use. After the start of the experiment, each sample was accurately weighed with an analytical balance and then soaked in the above-mentioned corresponding numbered corrosion solution, the experimental temperature was 40 C., and the linear speed of the test strips was 0.35 m/s. Air was not inlet in the soaking process, the surface rust was wiped off after continuous soaking for 48 hours, excess water was removed by using absolute ethanol after acid washing, alkali washing and water washing, the samples were dried and weighed again,

(29) the corrosion inhibition rate was measured according to the corrosion reduction, and the calculation formula of the corrosion rate is as follows:

(30) $X=\frac{8760\left(m-m_1\right)10}{st}$

(31) In the above formula, m is the final mass loss of the quality of the test strips soaked in the corrosion solution prepared above, unit g; m.sub.1 is the average mass loss of the quality of the test strips after the acid washing, alkali washing, water washing and absolute ethyl alcohol washing, unit g;

(32) s was the surface area of the test strips, unit cm.sup.2; p is the density of the test strips, unit g/cm.sup.3; t is the test time, unit h; 8760 is the number of hours equivalent to 1 year, unit h/a; 10 is the number of millimeters equal to 1 cm;

(33) The corrosion inhibition rate X.sub.2 of each sample is calculated by the corrosion rate measured by the above formula (the specific detection and calculation results are shown in table 1):

(34) $X_2\left(\%\right)=\frac{X_0-X_1}{X_0}100$

(35) In the formula: X.sub.0 is the corrosion rate of the sodium chloride corrosion test solution prepared above to the test strip, unit mm/a;

(36) X.sub.i is the corrosion rate of the corrosion test solutions prepared by the finished products of the above embodiments and comparative embodiments to the test strips, unit mm/a.

(37) TABLE-US-00001 TABLE 1 Sodium Comparative Comparative Comparative Comparative chloride Embodiment 1 Embodiment 2 Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Corrosion 0.5058 0.0756 0.0701 0.1385 0.1276 0.1162 0.1289 rate Corrosion / 85.05% 86.14% 72.62% 74.77% 77.03% 74.52% inhibition rate

(38) It can be seen from the corrosion results of carbon steel in Table 1 that the organic environment-friendly snow-melting agent of the present invention can significantly reduce the corrosion of standard carbon steel sheets, and the corrosion rate of sodium chloride to carbon steel is several times that of the organic snow-melting agent of the present invention; and the corrosion inhibition effect of the product of comparative embodiments are worse than that of the present invention.

(39) Test Experiment 2

(40) Ice Melting Speed of the Organic Environment-Friendly Snow-Melting Agent:

(41) According to the test method of snow and ice melting ability in the national standard of snow-melting salt, 200 g organic environment-friendly snow-melting agent products in embodiment 1, embodiment 2, comparative embodiment 1, comparative embodiment 2, comparative embodiment 3 and comparative embodiment 4 were weighed and placed in six 400 ml beakers respectively, and then were transferred to six 1000 ml volumetric flasks after dissolving in water, and then were shaken up and set for later use; the test solutions of the snow-melting agent products of embodiment 1, embodiment 2, comparative embodiment 1, comparative embodiment 2, comparative embodiment 3, and comparative embodiment 4 in each volumetric flask were sequentially marked as: test solution 1, test solution 2, test solution 3, test solution 4, test solution 5, test solution 6;

(42) six 150 mL sample vials of the same diameters and heights were taken and added 100 mL of water and placed in a cryostat at 10 C. to fully freeze; 25 mL of the above-mentioned test solutions 1, 2, 3, 4, 5, 6 were respectively moved into six 50 mL beakers and placed in a cryostat at 8 C. for 12 h for later use;

(43) the fully frozen sample vials were removed from the cryostat and weighed quickly (accurate to 0.1 g) after wiping the water and ice on the outer wall thereof, the standby test solutions 1, 2, 3, 4, 5, 6 were poured into the sample vials containing ice cubes one to one immediately, then the sample vials were put back into the cryostat at 10 C., and were taken out in 20 minutes, 40 minutes and 60 minutes respectively, the liquids in the sample vials were poured immediately, and the mass of the beakers and remaining ice cubes were weighed quickly, then pour the liquids back into the original sample vial, the obtained data of ability of melting snow and ice at each time period are shown in table 2:

(44) TABLE-US-00002 TABLE 2 Time (minutes) 0 20 40 60 Weight Weight of Weight Weight of Weight Weight of Weight Weight of of ice melting ice of ice melting ice of ice melting ice of ice melting ice Embodiment 1 100 0 89.8 10.2 77.5 22.5 65.6 34.4 Embodiment 2 100 0 90.2 9.8 78.6 21.4 66.9 33.1 Comparative 100 0 96.2 3.8 91.3 8.7 86.7 13.3 embodiment 1 Comparative 100 0 96.1 3.9 91.4 8.6 86.8 13.2 embodiment 2 Comparative 100 0 95.9 4.1 91.3 8.7 86.5 13.5 embodiment 3 Comparative 100 0 96.2 3.8 91.5 8.5 86.9 13.1 embodiment 4

(45) It can be seen that the co-existence of trace iron and aluminum can greatly improve the snow and ice melting effect by cooperating with the main components of the snow melting agent.

(46) According to comparative embodiment 3, when the contents of Fe and Al elements are too high, the snow-melting effect is poor.

(47) Test Experiment 3

(48) Freezing Point Test of the Organic Environment-Friendly Snow-Melting Agent:

(49) Sodium chloride (purity99.9%) and the organic environment-friendly snow melting agent products in embodiments 1, 2 and comparative embodiments 1, 2, 3, 4 were added into seven beakers respectively, water was added to prepare test solutions of a solute mass fraction of 18.0%. 70.0 ml of each test solution was removed and measured according to the requirements of SH/T 0090, and tested by B SY-188Z engine coolant freezing point tester, the result are shown in table 3.

(50) TABLE-US-00003 TABLE 3 Sodium Comparative Comparative Comparative Comparative chloride Embodiment 1 Embodiment 2 embodiment 1 embodiment 2 embodiment 3 embodiment 4 Freezing 14.3 19.2 19.7 8.3 8.8 9.1 8.6 point/ C.

(51) From the test data of each comparative embodiment, the freezing point of the salt snow-melting agent of the conventional carboxylic acid calcium magnesium is higher than that of the snow-melting agent of the sodium chloride, which is one aspect that the salt snow-melting agent of carboxylic acid calcium magnesium is inferior to the conventional sodium chloride; however, in the present application, the freezing point of the salt snow-melting agent of carboxylic acid calcium magnesium doped with the related trace elements reduces significantly.