Patent Application
20100090160
A portion of the disclosure of this patent document contains or may contain copyright protected material. The copyright owner has no objection to the photocopy reproduction by anyone of the patent document or the patent disclosure in exactly the form it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
This invention relates to production of a dust control product that over time exhibits residual dust control capabilities. The invention discloses a composition and a method for application of the product onto a surface to provide dust control and further allows for residual dust control after the curing process. The invention not only demonstrates initial and residual dust control it additionally limits moisture re-absorption during storage and transport.
The invention describes a composition for use in dust control on surfaces and it is particularly effective in mineral mining, processing and storage environments. The product is effective for use in the mining sector because it also reduces moisture re-absorption during storage and transport of the minerals. Further the invention relates to the method of use of the composition in relation to dust reduction and long term dust control.
The invention may be used to include dust control where the solids are selected from the group consisting of coal, clean coal, bauxite, iron ore, copper ore, sand, gravel, clay, dirt, phosphate rock, lead/zinc, taconite, beryllium, Trona, kaolin, titania, uranium, precious metals and the like. More than one type of solids may be present to the total surface for dust control.
Dust suppression is the reduction of the extent to which finely divided solid particulate material becomes suspended in the air. A variety of materials such as coal, sulfur, phosphate, clay, potash and other finely divided ores and minerals, generate dust in transfer and handling operations during mining, transportation, storage, and use.
Dust is a particularly severe safety and health hazard in coal mining, handling, and storage operations. Coal often chips into small fragments by the action of wind and rain, frictional movement due to motion in transit, and abrasion in handling. Respirable coal dust has a particle size of less than about 10 microns and its inhalation can lead to pneumoconiosis, i.e., “black lung disease”. Also, dust explosions due to spontaneous combustion may occur when the dust is confined to a small air space such as in coal mining operations.
It is known to suppress dust in mines by spraying with various aqueous systems containing chemical additives to improve working conditions and reduce the toxicological risks and explosion hazards. For example, U.S. Pat. No. 4,425,252 describes a method to abate coal dust using an anionic surfactant, preferably sodium dodecylbenzene sulphonate and a nonionic surfactant, preferably a polyethoxylated nonylphenol, in an aqueous formulation. The method comprises spraying the coal dust area with a formulation comprising water containing up to 0.1% by weight of the mixture of the anionic surfactant, i.e., a water soluble salt of an alkyl aryl sulfonic acid and nonionic surfactant having an HLB of from 10 to 16. Optimally, the mixture contains one or more cosolvents generally of the class of alkylene glycol monoalkyl ethers, C.sub.2 to C.sub.5 alkanols and mixtures thereof.
Furthermore, several techniques have been developed utilizing foamable compositions for suppressing coal dust. For example, U.S. Pat. No. 4,551,261 describes a foam comprising water, a foaming agent, and an elastomeric water insoluble polymer. A variety of anionic and nonionic surfactants and detergent wetting agents are described as useful foaming agents, and a variety of elastomeric and water insoluble synthetic organic polymer binders are described as useful elastomeric water insoluble polymers.
U.S. Pat. No. 4,971,720 relates to a method for suppressing dust process emissions. The method utilizes a foaming agent which may be a low salt tolerant surfactant selected from salts of fatty acids, alkyl sulphates, and alkyl aryl sulphonates.
U.S. Pat. No. 4,561,905 describes a coal dust suppression mixture of oil, water and a surfactant in the form of an emulsion that is diluted and foamed. The foam is then sprayed into a falling mass of coal. The oils suitable for use are described as heavy process oils and include asphalt dissolved in a moderately heavy oil, residual flush oils or relatively high viscosity fuel oil. The preferred oils have a viscosity in the range of from approximately 600 to 7,000 SUS at 38.degree. C., a pour point in the range of approximately −18.degree. to 21.degree. C., a molecular weight of at least 300 and a boiling point of at least 204.degree. C.
U.S. Pat. No. 4,944,892 teaches an aqueous composition which comprises a linear primary alcohol ethoxylate surfactant, a suitable scenting oil such as pine oil or lemon oil and water among other adjuvants.
U.S. Pat. No. 4,929,278 discloses an aqueous bath preparation which comprises essential oils such as orange peel oil, orange oil, lemon oil or the like. Further, the bath preparation comprises a soap or surfactant which may include straight chain alkyl benzenesulfonates, alkyl sulfuric acid ester, alkyl ether sulfuric acid ester and the like.
U.S. Pat. No. 3,367,878 shows a composition which comprises 20.2% by weight water, 1.0% by weight pine oil, 1.8% by weight sodium xylene sulphonate surfactant.
U.S. Pat. No. 4,175,062 teaches an aqueous composition which comprises 7.5% by weight of sodium dodecylbenzene sulfonate, 0.8% by weight of pine oil and other adjuvants.
Japanese Patent 44,495 discloses an aqueous composition which comprises 20% by weight of sodium lauryl benzene sulfonate and 1% by weight of D-limonene along with other adjuvants.
Thus, various techniques have been developed to suppress and control dust especially in the mining of minerals, and many of the techniques are effective for reducing dust. However, there is still a need for improvement in dust suppression. In relation to finely divided ores and mineral mining many of the prior techniques were developed without a need to address problems associated with modern mining practices.
Transport Component (carrier oil, acts to transport other reagents)
These carrier oils of hydrocarbons are extracted from petroleum crude oil (ex: low odor paraffin solvent, Escaid 110 solvent Exxon, Mineral Oils). These oils also come from crop sources, such as, Biodiesel, that is derived from corn or soybeans to name a few. Other crop sources also exist and should not limit this invention.
Dispersant (aids in effective surface coverage)
These materials could be derived from natural or synthetic sources (ex: orange oil, pine oil, essential oils, terpenes, cationic, nonionic, cationic and anionic ethoxylated surfactant materials and blends, thereof).
Surface Modifying Agent (elastomer)
This material is any substance that increases the formulations tackiness such as materials derived from rubber sources either natural (natural rubber latex, Union Carbide, NC-358) or synthetic (polyisoprene suspension, Kraton IR401).
Coupling Agent (aids in homogeneous blending)
These materials are derived from natural sources, such as, soybeans and other crops. These are phospholipids. (ex: ALC, Alcotee S, American Lecithin Company).
The current invention describes the following key aspects:
The current invention relates to a dust control composition comprised of an effective amount of a transport component, a dispersant and a surface modifying agent. This composition is for use on a wide variety of surfaces to assist in the dust reduction in an open or closed environment.
The dust control composition can also include a coupling agent that can assist in the overall appearance of the composition by making it more homogenous. The coupling agent may be a surfactant preferable one or more phospholipids.
The composition contains a transport component that can be a mixture of synthetic oils or natural oils. The preferred transport components are one or more of the following: biodiesel, mineral oils, low odor paraffin solvent, Escaid 110 solvent Exxon and paraffinic oils. Also the composition may include a curing control agent which can be used to control the curing time so it can be varied depending on the surface and the environment.
The dispersant component of the composition is preferably one or more of the following: orange oil, pine oil, essential oil, terpenes, cationic ethoxylates, nonionic ethoxylates, propoxylates and anionic ethoxylates.
The surface modifying agent of the composition can be derived from a natural source, such as natural rubber latex, or a synthetic source, such as a polyisoprene suspension.
The dust control composition contains the components in the following ranges; 50 to 98 percent transport component, 0.05 to 10 percent dispersant, 0.05 to 20 percent surface modifying agent and 0.1 to 50 percent coupling agent. The dust control composition has the components in the preferred range of 80 to 90 percent transport component, 0.5 to 2 percent dispersant, 0.5 to 5 percent surface modifying agent and 5 to 20 percent coupling agent.
The invention further includes a method using the dust control composition wherein it is applied to a surface in an effective amount to allow for the immediate elimination of dust particles and remain effective for an extended period of time. The composition is applied with a properly engineered spray bar or application device. The application of the composition is done with an effective amount to control residual dust for the storage or transportation of the surface and to prevent moisture re-absorption during storage and transport. The composition can be used on a wide variety of surfaces including but not limited to mined minerals, synthesized dry material, roads, coal, potash and/or phosphate.
The foregoing may be better understood by reference to the following examples, which are intended to illustrate methods for carrying out the invention and are not intended to limit the scope of the invention.
It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the invention and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.
The testing is conducted using a drop box apparatus where the dust control effectiveness of the claimed invention is demonstrated. The majority of the drop box apparatus is a hollow aluminum piece with a movable steel plate at the top of the apparatus where the sample is loaded and a detection system at the bottom consisting of a laser, power supply, detector, and removable piece necessary for cleaning. The system sits on a base that has an insert, which fits inside the aluminum part. The following is the test procedure used to evaluate the samples in the examples.
Only dry samples can be tested using this device.
If required, the materials were ground to dust in a ceramic container filled with steel spheres. Numerous spheres were placed into the ceramic container with the material to be tested and allowed to roll for a predetermined time period. The particles are then sifted through a #30 mesh screen to separate out larger particles.
The material is then heated to the appropriate temperature in an 180° F. oven for one hour (if required).
The appropriate amount of dust control agent is applied onto the dust, while still in the oven (if required), and mixed thoroughly.
The dust material dosed with dust control agent is then allowed to cool to room temperature prior to testing in the drop box apparatus.
Turn on the drop box detection system and begin data acquisition system.
Secure the steel tray in a horizontal position using a magnets
Load a predetermined amount of sample onto the swing down tray (sample size of 5-15 g).
Capture the data from data acquisition system.
Begin trial by connecting to the detection system.
Officially start recording optical densities.
The detector will now determine the amount of light scattering over time.
A baseline is found first to ensure no contaminants are in the laser field.
After a baseline is set, the magnet can be removed causing the sample to drop down the apparatus resulting in an increase in optical density.
After a predetermined amount of time the data collecting is stopped.
