USE OF AQUEOUS SOLUTION OF ORGANIC AMMONIUM CARBOXYLATE IN PREVENTING DUSTING OF FINE MATERIAL AND COMBINATION OF AN AQUEOUS SOLUTION OF ORGANIC AMMONIUM CARBOXYLATE AND FINE MATERIAL

Abstract

A method to control dusting of sand, crushed stone, mineral dust, metal powder and the like by using an aqueous solution of organic of ammonium carboxylate is disclosed.

Claims

1. A method to prevent dusting of fine materials, said method comprising the steps of providing a mist of an aqueous solution of organic ammonium carboxylate of formula (I):
[NR.sup.1R.sup.2R.sup.3R.sup.4].sup.+.sub.n [R.sup.5(COO)].sup.n, (I), in which R.sup.1, R.sup.2, and R.sup.3 are selected from the group composing of hydrogen and methyl, R.sup.4 is a C.sub.1-C.sub.4-alkyl substituted with a hydroxyl group, R.sup.5 is hydrogen or methyl and n is 1, applying the mist on the fine material, wherein the fine material is selected from the group composing of sand, crushed stone, minerals and metal powder.

2. The method of claim 1, wherein R.sup.1, R.sup.2 and R.sup.3 are all hydrogen and R.sup.4 is an ethyl substituted with a hydroxyl group, preferably 2-hydroxy ethyl.

3. The method of claim 1, wherein R.sup.1, R.sup.2 and R.sup.3 are all methyl and R.sup.4 is an ethyl substituted with a hydroxyl group, preferably 2-hydroxy ethyl.

4. The method of claim 1, wherein the organic ammonium carboxylate of formula (I) is a salt of formic acid and monoethanolamine or a salt of acetic acid and monoethanolamine.

5. The method of claim 1, wherein the concentration of the organic ammonium carboxylate of formula (I) in the aqueous solution, is in the range of 1-7% wt-%, preferably in the range of 3-5 wt-% while the freezing point of the composition is kept in the range of 5 to 50 C.

6. The use as defined in claim 1, wherein the aqueous solution of organic ammonium carboxylate of formula (I) contains organic ammonium carboxylate of formula (1) and water in a weight ratio in the range of 1:50-1:15, preferably in the range of 1:33-1:20.

7. The method of claim 1, wherein the aqueous solution of organic ammonium carboxylate of formula (I) contains distilled water only.

8. The method of claim 1, wherein concentration of sodium, potassium, calcium and magnesium is 0 M.

9. The method of claim 1, wherein aqueous organic ammonium carboxylate of formula (I) is additionally admixed with compounds selected from the group comprising glycols, preferably ethylene glycol or propylene glycol, glycerols and viscosity modifying polymers, so that said aqueous composition contains 5 to 97.5 wt-% of water.

10. The method of claim 1, wherein aqueous organic ammonium carboxylate of formula (I) is additionally admixed with auxiliary substances such as additional corrosion inhibitors, biocides, coloring agents, surfactants, and viscosity intensifiers, so that the concentration of auxiliary substances will be in the range of 0.001 to 10 wt-% from the total weight of aqueous solution.

11. The method of claim 1, wherein the organic ammonium carboxylate of formula (1) contains formic acid, acetic acid and monoethanolamine or trimethylmonoethanolamine.

12. The method of claim 1, wherein aqueous organic ammonium carboxylate of formula (I) is used 1-2 I per 1000 kg of crushed stone, preferably 1.2-1.5 I per 1000 kg of crushed stone.

13. The method of claim 1, wherein freezing point of said aqueous solution is from 3 C. to 15 C. preferably from 5 C. to 10 C.

14. The method of claim 1 further including a step wherein aqueous organic ammonium carboxylate of formula (I) is prepared by diluting, in situ, concentrated solution of water and organic ammonium carboxylate of formula (I) with water, in which said concentrated solution the concentration of organic ammonium carboxylate of formula (I) is 50 wt-% or 85 wt-%

15. The method of claim 1, further including a step wherein the aqueous organic ammonium carboxylate of formula (I) is prepared by mixing, in situ, an aqueous solution of 1-5 wt-% of amine with an aqueous solution of 1-5 wt-% of acid

16. A combination of droplets of aqueous solution of organic ammonium carboxylate of formula (I):
[NR.sup.1R.sup.2R.sup.3R.sup.4].sup.+.sub.n [R.sup.5(COO)].sup.n, (I), in which R.sup.1, R.sup.2, and R.sup.3 are selected from the group composing of hydrogen and methyl, R.sup.4 is a C.sub.1-C.sub.4-alkyl substituted with a hydroxyl group, R.sup.5 is hydrogen or methyl and n is 1, and fine material selected from the group composing of sand, crushed stone, minerals and metal powder, wherein said aqueous solution of organic ammonium carboxylate of formula (I) has been sprayed as a mist onto the surface of said fine material.

17. The combination defined in claim 16 comprising of droplets aqueous solution of organic ammonium carboxylate of formula (I) and fine material, wherein drying of said combination will lead on the one hand to water loss and on the other hand absorbing of water by way of the organic ammonium carboxylate of formula (I) resulting in keeping the surface of said fine material moist.

18. The combination defined in claim 16, comprising droplets of aqueous solution of organic ammonium carboxylate of formula (I) and fine material, wherein organic ammonium carboxylate of formula (I) will absorb water after water content of said aqueous solution have dropped at or below 15 wt-%.

19. The combination defined in claim 16 comprising droplets of aqueous solution of organic ammonium carboxylate of formula (I), and fine material, wherein carboxylate originate from acetic acid, in form of fluid and having BOD (biological oxygen demand) of 0.64 mg of O.sub.2 at 20 C. for liter of said fluid in 5 days.

20. The combination defined in claim 16 comprising droplets of aqueous solution of organic ammonium carboxylate of formula (I), and fine material, wherein carboxylate originate from acetic acid, in form of fluid, and having COD (chemical oxygen demand) of 0.64 mg O.sub.2 at 20 C. for liter of said fluid in 5 days.

Description

SHORT DESCRIPTION OF THE FIGURES

[0044] FIG. 1 shows the freezing points of aqueous solutions of organic ammonium carboxylate of formula (I), wherein R.sup.5=H (formiate).

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0045] The invention is described below in more greater details with the help of examples. Person skilled in the art will recognize that the properties of the compositions studied are such that they will make ideal mineral dust control aqueous solutions having also freezing point depressant properties for binding dusting of streets, ore mines, horse tracks etc.

[0046] In the following non-restricting examples we have presented some specific applications and properties of aqueous solutions comprising organic ammonium carboxylate of formula (I) as well as combinations comprising aqueous solution of organic ammonium carboxylate of formula (I) and fine material selected from the group composing of sand, crushed stone, minerals and metal powder.

EXAMPLE 1

[0047] An ionogenic solution for controlling mineral dust formation was prepared by mixing 1 mole of formic acid (99%) with 1 mole of monoethanolamine (99%). Distilled water was added to the fluid mixture in order to made 3-5% by weight aqueous solution.

[0048] The freezing point of the solution was below 5 C., the electrical conductivity of the fluid was 61 mS/cm at 26 C., and pH of the fluid was 7.55 (measured directly from the solution).

EXAMPLE 2

[0049] An aqueous solution was prepared by mixing 1 mole of formic acid (99%) with 1 mole of monoethanolamine (99%). Distilled water was added to the fluid mixture in order to made 3-5 by weight solution in water.

[0050] The freezing point of the solution was below 5 C., the Brookfield DV-I viscosity (20 rpm) was 10 mPas at 20 C., 10 mPas at 10 C., 10 mPas at 0 C., and Bohlin VOR viscosity (shear rate 23.1 1/s) was 4 mPas at 10 C., 3 mPas at 20 C., 2 mPas at 40 C., and 1.5 mPas at 60 C. The electrical conductivity of the fluid was 65 mS/cm at 26 C., and pH of the fluid was 7.54 (measured directly from the solution).

EXAMPLE 3

[0051] Solutions in examples 6 and 7 in the below tables have been made in the same way as presented in examples 1-2, that is, by mixing 1 mole of an ammonium cation source and 1 mole of a carboxyl anion source (unless otherwise shown) together for obtaining a concentrated fluid and then adding water to the concentrated fluid, for obtaining diluted solutions.

TABLE-US-00001 TABLE 1 In table 1 formation of possible precipitates from fluids and diluted solutions obtained from fluids is shown. Temperature was 20-25 C. fluid Wt-% from solution pH of 2% Code/ex fluid 100 90 80 60 40 20 5 solution EAE/6 ethanolamine/ Clear Clear Clear Clear Clear Clear Clear 6.8 acetic acid EAM/7 ethanolamine/ Clear Clear Clear Clear Clear Clear Clear 3.7 formic acid

TABLE-US-00002 TABLE 2 The fluid and solution samples from selected examples of table 1 were subjected to chilling to a temperature of +4 C. and then to further cooling to a temperature of 20 C. In these temperatures the possible turbidity, precipitation of these samples was observed. ex 100 90 80 60 40 20 5 Temperature +4 C. 6 ethanolamine/ Clear Clear Clear Clear Clear Clear Clear acetic acid 7 ethanolamine/ Clear Clear Clear Clear Clear Clear Clear formic acid Temperature 20 C. 6 ethanolamine/ Clear/liquid Clear/liquid Clear/liquid Clear/ Clear/liquid frozen frozen acetic acid state state state liquid state state 7 ethanolamine/ Clear/ Clear/ Clear/liquid Clear/ frozen frozen frozen formic acid liquid liquid state liquid state state state

[0052] As can be seen from table 1 and table 2 water based solutions of organic of ammonium carboxylates are clear solutions independent whether they are diluted or not. This means that when they are used in controlling mineral dust they have no tendency to salt out after sprayed onto surface of crushed stones, sand, soil or metal. Therefore they do not interfere for example vehicle brakes or transport belts used in mining processes.

[0053] Table 3

[0054] In table 3 results from viscosity measurements compositions of examples 6 and 7 are given. Viscosity was measured with Bohlin method (bold numbers) at shear rate 23.1 1/s and with Brookefield method (normal numbers) at shear rate 20 rpm. Additionally, electrical conductivity, pH and redox potential was measured for these compositions comprising fluids and solutions prepared from these fluids by adding distilled water.

TABLE-US-00003 TABLE 3 monoethanolamine/acetic acid fluid Wt-% 100 90 80 60 40 20 5 from solution water water wt-% 0 10 20 40 60 80 95 C. VISCOSITY Bohlin shear rate mPas VOR 23.1 1/s viscosity 20 rpm sp3 Brookfield DV-I viscosity viscosity mPas/ 20 >20000 >20000 12450 170 35 X X (repeat) 20 >20000 16740 1700 80 20 X X 10 >20000 5150 700 60 15 10 5 0 27850 2160 330 40 10 10 5 10 15250 1152 210 23 6 2 1.7 20 5665 556 118 15 5 2 1.3 40 1220 154 41 8 3 1.5 1.1 60 345 63 20 5 2 1 0.7 conductivity mS/cm 0.534 2.24 7.1 25.9 46.9 47.8 20.2 T C. 25.4 25.9 26 25.6 25.4 25.1 24.9 pH C. 22 7.96 7.81 7.68 7.34 7.07 6.87 6.79 REDOX +31 +54 +69 +107 +146 +179 +216 fluid Wt-% 100 90 80 60 40 20 5 Composition: from monoethanolamine/formic acid solution water water wt-% 0 10 20 40 60 80 95 pale oily VISCOSITY Bohlin shear rate light liquid mPas VOR 23.1 1/s C. viscosity 20 rpm sp3 Brookfield DV-I viscosity viscosity mPas/ 30 20 4350 680 230 30 10 X X 10 2830 410 130 20 10 5 X 0 1335 240 75 15 10 5 5 10 646 123 41 9 4 2 1.5 20 325 72 26 6 3 1.7 1.2 40 119 31 13 4 2 1.2 0.95 60 47 17 7 3 1.5 1.1 0.9 conductivity mS/cm 15.9 27.3 40.4 61 65 46.9 16 T C. 26.1 25.9 25.8 25.6 25.5 25.5 25.8 pH/22 C. 7.75 7.67 7.6 7.55 7.54 7.53 7.51 REDOX potential 321 244 164 110 75 48 +4

[0055] As can be seen from table 3 the viscosity of compositions varies considerably depending on the quality of the fluid in a composition and fluidsolvent proportion (w/w). No solid crystals will be formed for instance if one uses combination ethanol amine/formic acid. Avoiding solid crystals is also a beneficial property for instance for an aqueous solution used for dust control.

[0056] FIG. 1 shows the freezing points of aqueous solutions of organic ammonium carboxylate of formula (I), wherein R.sup.5=H (formiate). Table 4 below shows the freezing points of selected aqueous solutions of organic ammonium carboxylate of formula (I), wherein R.sup.5=H (formiate).

TABLE-US-00004 TABLE 4 Samples of organic ammonium carboxylate of formula (I) in water and their freezing points: Sample Concentration (wt-%) Freezing point ( C.) Water 0 0 HTF-20 20 8.96 HTF-25 25 12.44 HTF-30 30 16.51 HTF-35 35 20.13 HTF-40 40 29.33 HTF-45 45 39.48 HTF-50 50 54.95 HTF-55 55 63.01 HTF-60 60 84.50

[0057] As can be seen from FIG. 1 and table 4: as the concentration of water solutions of organic ammonium carboxylate of formula (I) increases it will readily lead to lower freezing points. For example, those aqueous solutions of organic ammonium carboxylate of formula (I) presented in FIG. 1 and table 4 having concentration about 10 wt-% have a freezing point about 5 C. However, when the concentration of organic ammonium carboxylate of formula (I) in the aqueous solution increases, the freezing point of the aqueous solutions falls considerably, for example when the concentration of aqueous solution is 30 (wt-%) the freezing point of said aqueous solution is about 20 C. When the concentration of aqueous solution is 60 wt-%) the freezing point of said aqueous solution is about 85 C. The freezing point of 5 C. corresponds the freezing point of aqueous solutions of organic ammonium carboxylate of formula (I) which is ready-to-use (1-7 wt % aqueous solution). The freezing point of 30 C and 85% corresponds the freezing point of the aqueous solution of organic ammonium carboxylate of formula (I) which has been sprayed onto surface of fine material when water has been evaporated.

[0058] The invention is illustrated by following embodiments:

[0059] 1. The use of aqueous solution of organic ammonium carboxylate of formula (I):

[NR.sup.1R.sup.2R.sup.3R.sup.4].sup.+.sub.n [R.sup.5(COO)].sup.n, (I),

[0060] in which R.sup.1, R.sup.2, and R.sup.3 are selected from the group composing of hydrogen and methyl, R.sup.4 is a C.sub.1-C.sub.4-alkyl substituted with a hydroxyl group, R.sup.5 is hydrogen or methyl and n is 1,

[0061] as a mist, in preventing dusting of fine material selected from the group composing of sand, crushed stone, minerals and metal powder and in lowering the freezing point of said aqueous solution.

[0062] 2. The use defined in above embodiment, wherein R.sup.1, R.sup.2 and R.sup.3 are all hydrogen and R.sup.4 is an ethyl substituted with a hydroxyl group, preferably 2-hydroxy ethyl.

[0063] 3. The use defined in above embodiments, wherein R.sup.1, R.sup.2 and R.sup.3 are all methyl and R.sup.4 is an ethyl substituted with a hydroxyl group, preferably 2-hydroxy ethyl.

[0064] 4. The use defined in above embodiments, wherein the organic ammonium carboxylate of formula (I) is a salt of formic acid and monoethanolamine or a salt of acetic acid and monoethanolamine.

[0065] 5. The use as defined in above embodiments, wherein the concentration of the organic ammonium carboxylate of formula (I) in the aqueous solution, is in the range of 1-7% wt-%, preferably in the range of 3-5 wt-% while the freezing point of the composition is kept in the range of 5 to 50 C.

[0066] 6. The use as defined in above embodiments, wherein the aqueous solution of organic ammonium carboxylate of formula (I) contains organic ammonium carboxylate of formula (1) and water in a weight ratio in the range of 1:50-1:15, preferably in the range of 1:33-1:20.

[0067] 7. The use as defined in above embodiments, wherein the aqueous solution of organic ammonium carboxylate of formula (I) contains distilled water only.

[0068] 8. The use as defined in above embodiments wherein the concentration of sodium, potassium, calcium and magnesium is 0 M.

[0069] 9. The use as defined in any of above embodiments, wherein aqueous organic ammonium carboxylate of formula (I) is additionally admixed with compounds selected from the group comprising glycols, preferably ethylene glycol or propylene glycol, glycerols and viscosity modifying polymers, so that said aqueous composition contains 5 to 97.5 wt-% of water.

[0070] 10. The use as defined in above embodiments, wherein aqueous organic ammonium carboxylate of formula (I) is additionally admixed with auxiliary substances such as additional corrosion inhibitors, biocides, coloring agents, surfactants, and viscosity intensifiers, so that the concentration of auxiliary substances will be in the range of 0.001 to 10 wt-% from the total weight of aqueous solution.

[0071] 11. The use defined in above embodiments, wherein the organic ammonium carboxylate of formula (1) contains formic acid, acetic acid and monoethanolamine or trimethylmonoethanolamine.

[0072] 12. The use defined in above embodiments, wherein aqueous organic ammonium carboxylate of formula (I) is used 1-2 I per 1000 kg of crushed stone, preferably 1.2-1.5 I per 1000 kg of crushed stone.

[0073] 13. The use defined in above embodiments, wherein freezing point of said aqueous solution is from 3 C. to 15 C. preferably from 5 C. to 10 C.

[0074] 14. The use defined in above embodiments, further including a step wherein aqueous organic ammonium carboxylate of formula (I) is prepared by diluting, in situ, concentrated solution of water and organic ammonium carboxylate of formula (I) with water, in which said concentrated solution the concentration of organic ammonium carboxylate of formula (I) is 50 wt-% or 85 wt-%

[0075] 15. The use defined in above embodiments, further including a step wherein the aqueous organic ammonium carboxylate of formula (I) is prepared by mixing, in situ, an aqueous solution of 1-5 wt-% of amine with an aqueous solution of 1-5 wt-% of acid

[0076] 16. A combination of droplets of aqueous solution of organic ammonium carboxylate of formula (I):

[NR.sup.1R.sup.2R.sup.3R.sup.4].sup.+.sub.n [R.sup.5(COO)].sup.n, (I),

[0077] in which R.sup.1, R.sup.2, and R.sup.3 are selected from the group composing of hydrogen and methyl, R.sup.4 is a C.sub.1-C.sub.4-alkyl substituted with a hydroxyl group, R.sup.5 is hydrogen or methyl and n is 1,

[0078] and fine material selected from the group composing of sand, crushed stone, minerals and metal powder,

[0079] wherein said aqueous solution of organic ammonium carboxylate of formula (I) has been sprayed as a mist onto the surface of said fine material.

[0080] 17. The combination defined in above embodiment comprising of droplets aqueous solution of organic ammonium carboxylate of formula (I) and fine material, wherein drying of said combination will lead on the one hand to water loss and on the other hand absorbing of water by way of the organic ammonium carboxylate of formula (I) resulting in keeping the surface of said fine material moist.

[0081] 18. The combination defined in above embodiments, comprising droplets of aqueous solution of organic ammonium carboxylate of formula (I) and fine material, wherein organic ammonium carboxylate of formula (I) will absorb water after water content of said aqueous solution have dropped at or below 15 wt-%,

[0082] 19. The combination defined in above embodiments comprising droplets of aqueous solution of organic ammonium carboxylate of formula (I), and fine material, wherein carboxylate originate from acetic acid, in form of fluid and having BOD (biological oxygen demand) of 0.64 mg of O.sub.2 at 20 C. for liter of said fluid in 5 days.

[0083] 20. The combination defined in above embodiments comprising droplets of aqueous solution of organic ammonium carboxylate of formula (I), and fine material, wherein carboxylate originate from acetic acid, in form of fluid, and having COD (chemical oxygen demand) of 0.64 mg O.sub.2 at 20 C. for liter of said fluid in 5 days.