GB2279079A - Aqueous dust suppressant composition comprising oil and emulsifier - Google Patents

Abstract

A dust suppressant composition comprises an oil or mixture thereof, emulsifier, water and optionally other additives, especially a wax.

Description

DUST SUPPRESSANT COMPOSITION The present invention relates to dust suppressant compositions and more particularly to compositions for suppressing dust on dirt roads and in the general area of mining operations where there is likely to be substantial creation of dust as a result of the mining activities.

It has been proposed to suppress dust by application of a bitumen solution and emulsion over a dust laden area. However, the use of such a product can give rise to health and safety problems and also may cause potential environmental problems. Conventional dust suppressants also tend to dry to form a crust which does not permit combination with fresh dust which may settle.

According to one aspect of the present invention there is provided a dust suppressant composition comprising: an oil or mixture of oils; emulsifier; water; and optionally other additives.

According to another aspect of the present invention there is provided a method for suppressing dust on a dust laden area which comprises applying the dust suppressant composition defined above to the dust laden area.

Preferably the composition also contains wax and, optionally, additives such as wetting agent, biocide, anti-foaming agent, antioxidant. The oil may be a biodegradable oil, a non-biodegradable oil or a mixture of biodegradable and/or non-biogradableoils. However, for environmental reasons the use of a biodegradable oil or a mixture of such oils is preferred.

The composition is mixed with water to form an emulsion which is applied usually by means of a spray process. The composition may be mixed with water in an amount ranging from (by weight) 50% water and 50% composition to 95% water and 5% composition. The suppressant composition may be applied by a spray process and when sprayed onto an area subject to traffic (particularly vehicular traffic) will be subject to mechanical agitation by the action of the vehicle tyres whereby the composition will be inter-mixed with dust and rock particles to form a waterproof, pliable, sealed surface for the road. The sealed surface thus formed will also entrap further dust which settles and which will be subject to mechanical action by the passage of vehicular and other traffic.

The invention will now be further described by way of example only.

The dust suppressant composition, in accordance with preferred embodiments of the invention, comprises: biodegradable oil and/or non-biodegradable oil; wax; emulsifier; water; and optionally other additives as may be required.

It is preferred that the oil used in the composition is only biodegradable in order to minimise potential environmental problems, the characteristics of the biodegradable oil being such that the oil exhibits improved biodegradability and lower toxicity than conventional mineral oils. The biodegradable oil may be a synthetic ester, a vegetable oil, an animal oil, or a mixture of vegetable and animal oils.

In circumstances where a non-biodegradable oil is used, the oil should exhibit a slow rate of decomposition when subjected to naturally occurring organisms. Suitable oils for this purpose are heavy mineral oils, for example, those known as solvent brightstocks.

The wax used in the composition is preferably obtained from vegetable material such as canuba or bees wax or from mined materials such as montan or petroleum derived products such as paraffin wax.

The emulsifier in the composition provides stability and the composition of the emulsifier can be such that it is biodegradable or non-biodegradable. Suitable emulsifiers include nonylphenol ethoxylates such as TERIC GN9 (registered trade mark), ammonium salt of sulphated-4-ethoxy-nonylphenol e.g. RHODAPEX CO 436 (registered trade mark), naphthalene sulfonates, e.g. TAMMOL NN9104 (registered trade mark), oleic acid, triethanolamine and quaternary amine salts.

Optional additives may include wetting agents, a suitable wetting agent being ethoxylated alcohol, for example, TERIC G9A6 (registered trade mark). Other additives may include biocides, antifoaming agents and antioxidants.

In some instances the wax may be omitted and this may provide a satisfactory dust suppressant on surfaces where there is substantially no traffic. However, the wax tends to act as a binder for dirt and rock particles and is necessary on surfaces which are subject to traffic Preferably, the components of the composition are present in the following amounts (by weight): oil 10% to 70% wax 5 to 50% emulsifier 0.01 to 10% water 10% to 80%.

The characteristics of the composition will, of course, be dependent on the proportion of the constituents and also on the nature of the constituents and these are capable of wide variation within the parameters specified in order to obtain desired characteristics. For example, the composition may be required to remain in a pliable state so that dust falling on the composition after application is absorbed.

This may be particularly desirable on areas subject to vehicular traffic.

On areas subjected to pedestrian traffic it may alternatively be desirable for the composition to harden in order to prevent the composition from being picked up on the soles of the feet. The composition is mixed with water in the proportions indicated previously to form an emulsion and, preferably, is sprayed onto the surfaces to be treated. When the composition is sprayed onto a surface subject to vehicular traffic, the passage of vehicles will tend to mechanically agitate the composition and mix it with the underlying dust and rock particles to form a soft pliable surface which can absorb further dust which may settle.

Examples of specific compositions, in accordance with preferred embodiments of the invention, will now be described.

EXAMPLE 1 Weight % solvent brightstock mineral oil 52.3 water 34.2 montan wax 5.0 nonylphenol ethoxylate (emulsifier) 4.0 naphthalene sulphonate (emulsifier) 3.0 ammonium salt of sulphated-4-ethoxy nonylphenol (emulsifier) 1.5 The emulsifiers used in the above composition provides a suppressant composition which sets to a relatively, soft, pliable state which can reabsorb dust.

EXAMPLE 2 Weight % water 47 montan wax 5 solvent brightstock mineral oil 45 nonylphenol ethoxylate (emulsifier) 2.0 fatty quaternary amine salt (emulsifier) 1.0 This composition will tend to set to a relatively hard state.

EXAMPLE 3 Weight % water 48.7 solvent brightstock mineral oil 37.3 paraffin wax 10.0 nonylphenol ethoxylate (emulsifier) 4.0 The constituents of the composition are such that it will set to a relatively soft, pliable state which can reabsorb dust.

EXAMPLE 4 WeiAht % rapeseed oil 52.3 water 34.2 stearic acid (emulsifier and wax) 10.00 triethanolamine (emulsifier) 3.00 Irganox L1 18 (antioxidant) 0.5 This composition provides a material when mixed with road base to form a pliable, biodegradable mixture which reabsorbs dust.

EXAMPLE 5 Weight % water 47 montan wax 5 blown canola 45 fatty acid ethoxylate (emulsifier) 2.0 fatty quaternary amine salt (emulsifier) 1.0 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Claims (16)

1. A dust suppressant composition comprising: an oil or a mixture of oils; an emulsifier; water; and optionally other additives.

2. A dust suppressant composition according to Claim 1, wherein the oil or mixture of oils is a biodegradable oil, a nonbiodegradable oil or a mixture of biodegradable and/or nonbiodegradable oils.

3. A dust suppressant composition according to Claim 2, wherein the biodegradable oil is a synthetic ester, vegetable oil, animal oil or mixture thereof.

4. A dust suppressant composition according to Claim 2, wherein the non-biodegradable oil is a heavy mineral oil.

5. A dust suppressant composition according to Claim 4, wherein the heavy mineral oil is a solvent brightstock.

6. A dust suppressant composition according to any one of the preceding claims, wherein the amount of oil or mixture of oils is about 10% to about 70% by weight of the total composition.

7. A dust suppressant composition according to any one of the preceding claims, wherein the emulsifier is selected from nonylphenol ethoxylates, ammonium salt of sulphated 4 ethoxy-nonylphenol, naphthalene sulphonates, oleic acid, triethanol amine and quaternary amine salts.

8. A dust suppressant composition according to any one of the preceding claims, wherein the amount of emulsifier is about 0.01% to about 10% by weight of the total composition.

9. A dust suppressant composition according to any one of the preceding claims, wherein the other additives are selected from wetting agents, biocides, anti-foaming agents and anti-oxidants.

10. A dust suppressant composition according to Claim 9, wherein the wetting agent is an ethoxylated alcohol.

11. A dust suppressant composition according to any one of the preceding claims which further comprises a wax.

12. A dust suppressant composition according to Claim 11, wherein the wax is obtained from vegetable or mined materials.

13. A dust suppressant composition according to Claim 11 or Claim 12, wherein the wax is canuba wax, bees wax or paraffin wax.

14. A dust suppressant composition according to any one of Claims 11 to 13, wherein the amount of wax is about 5% to about 50% by weight of the total composition.

15. A method for suppressing dust on a dust laden area which comprises applying a dust suppressant composition, according to any one the preceding claims, to the dust laden area.

16. Dust suppressant compositions or methods involving them, substantially as hereinbefore described with reference to the Examples.