COMPOSITION FOR DUST SUPPRESSION

Abstract

The invention relates to an aqueous composition for the suppression of dust, comprising 1) an anionic surfactant; 2) an amphoteric surfactant; 3) a Bacillus species; and 4) a carbohydrate-based feedstock on which the Bacillus can grow. The composition is capable of forming a foam. When mixed with dust, the composition, in particular the foam thereof, is effective in preventing the dust from becoming airborne. Further, when applied before grinding or milling a material, the spreading of dust during and after the grinding or milling is effectively prevented.

Claims

1. Aqueous composition for the suppression of dust, comprising an anionic surfactant; an amphoteric surfactant; a Bacillus species; a carbohydrate-based feedstock on which the Bacillus can grow; wherein the composition is capable of forming a foam.

2. Composition according to claim 1, wherein the anionic surfactant comprises one or more surfactants selected from the group of C10-C20 alpha-olefin sulfonates, linear alkylbenzene sulfonates and branched alkylbenzene sulfonates.

3. Composition according to claim 1, wherein the anionic surfactant constitutes 35-65 wt. % of the total composition, based on the dry matter content, in particular 45-60 wt. %.

4. Composition according to claim 1, wherein the amphoteric surfactant comprises an amphoteric surfactant selected from the group of alkyliminodipropionates, betaine and substituted betaine such as a C12 or C14 dimethyl betaine.

5. Composition according to claim 1, comprising one or more strains or spores of a Bacillus species selected from the group of Bacillus subtilis, Bacillus amyloliquefaciens, Bacillus megaterium, Bacillus licheniformis, Bacillus atropheaus, Bacillus simplex, Bacillus velezensis, Bacillus cereus and Bacillus pumilus.

6. Composition according to claim 1, wherein the carbohydrate-based feedstock comprises a glucoside, in particular an alkyl glucoside such as decyl glucoside or lauryl glucoside.

7. Composition according to claim 1, wherein the dry matter content is in the range of 0.02-1.00 wt. %, in particular in the range of 0.02-0.50 wt. %.

8. A foam comprising the composition according to claim 1, wherein the foam has a density in the range of 1-200 kg/m.sup.3, in particular in the range of 5-100 kg/m.sup.3, more in particular in the range of 10-50 kg/m.sup.3.

9. Dust comprising a composition according to claim 1.

10. Dust comprising a foam of claim 8.

11. Method for preparing a foam according to claim 9, comprising providing a composition; then mixing the composition with air.

12. Method according to claim 11, wherein the composition has a dry matter content in the range of 0.02-1.00 wt. %, in particular in the range of 0.02-0.50 wt. %; and is further diluted by adding at least 50 parts of water prior to mixing it with air, preferably 9 120 parts of water.

13. Method for suppressing dust and for preparing a dust according to claim 9, comprising providing dust; then mixing the dust with a composition.

14. Method according to claim 13, wherein the composition is a foam according to claim 8.

15. Method according to claim 13, wherein the method is followed by sieving the dust.

16. Method for grinding or milling matter and preparing a dust according to claim 9, comprising applying a foam to the matter that needs to be ground or milled; then grinding or milling the resulting matter.

17. Method according to claim 13, wherein the amount of carbohydrate-based feedstock in the foam or composition is in the range of 0.0025-0.025 wt. % of the composition or the foam.

Description

EXAMPLES

Experimental Set-Up

[0074] The amount of dust formation with and without the dust-suppressing composition of the invention was determined with the following set-up. Pieces of stony material are collected on a conveyor belt. Halfway the conveyor belt, eight nozzles (capacity number BF 6530) with an equivalent bore with a diameter of 3.28 mm were positioned above the belt, designed to dose the foam composition of the invention under an angle of 50° with the belt in the direction of translation of the belt. The end part of the conveyor belt is arranged above a dumpster, allowing the material to drop into the dumpster and to collect in the dumpster. The throughput of the material is 60 tons of per hour. The dumpster was covered with plastic, leaving only a small opening for the material to enter the dumpster. In this way, a more or less closed compartment is formed above the surface of the material that is collected in the dumpster. In the compartment, a fine dust measuring device (Fidas® 200 S connected to a GilAir-3 Air Sampling Pump) was placed that can quantitatively measure the presence of PM 10 and PM 2.5 dust, which is defined as particulate matter with a particle size of 10 μm and 2.5 μm, respectively.

Experimental Procedure

[0075] The starting material for the process is formed by a dry mixture of 400 kg of debris with 25 kg of cement. The aqueous composition of the invention comprises, based on the dry matter content, [0076] 40 wt. % of sodium C14-16 olefin sulfonate (CAS Number: 68439-57-6); [0077] 15 wt. % of alcohols, C12-14, ethoxylated, sulfates, sodium salts (CAS Number: 68891-38-3); [0078] 20 wt. % of betaine (CAS Number: 107-43-7); [0079] 1 wt. % of a blend of Bacillus spores; [0080] 24 wt. % of laurylglycoside (CAS Number: 110615-47-9).

[0081] Just prior to its conversion into a foam and its application as a dust-suppressant, a concentrate of the composition with a dry matter content of 0.5 wt. % is diluted 100-fold.

[0082] General procedure: the cement-debris mixture is poured onto the vibrating screen and the matter that passes the screen is collected at the moving conveyor belt. During the transport of the matter over the belt, foam of the invention may be dosed to the matter. When the matter arrives at the end of this belt, it falls into the opening above the dumpster, passes the compartment with the fine dust measuring device and collects in the dumpster. During this process, the concentration of dust particles is measured in the atmosphere of the compartment.

[0083] Two different runs were performed; a first run wherein no means for the suppression of dust were applied (comparative run) and a second run wherein a composition of the invention was applied (dust suppressing run). The latter was performed by spraying the composition of the invention as a foam on the matter on the moving conveyor belt. The consumption of the composition of the invention was 3 kg per hour and the consumption of water as the diluent was 300 L per hour. Thus, given that 0.015 kg of composition, based on the dry matter content, is used to treat 60 tons of material, the mass ratio of the applied composition to the treated material is 1:4,000,000. The mass ratio of the applied composition as such (i.e. including the water) to the treated material is 1:198. The air pressure in the nozzles was 0.75 bars. The experiments were carried out in open air under dry, sunny, and windless weather conditions.

Results

[0084] During both runs, the concentration of dust (PM 10 and PM 2.5) was measured in the air of the compartment. The results are displayed in Table 1; the displayed concentrations are the average of two measurements.

TABLE-US-00001 TABLE 1 Measured concentrations of PM 10 and PM 2.5 Concentration of Concentration of PM 10 (mg m.sup.−3) PM 2.5 (mg m.sup.−3) First run (reference run) 19.3 0.83 Second run (invention run) 1.7 0.47

CONCLUSIONS

[0085] The concentration of PM 10 is decreased by a factor of 11.4 and the concentration of PM 2.5 by a factor of 1.8. Thus, a dust suppression method of the invention is highly effective.