Experimental Research On Compound Coal Dust Suppressant Based On Molecular Modification Technology

Dust has been a serious problem in coal mine,both underground coal mine and open pit coal mine,suffered by dust hazards.The diffuse dust has a great impact on the health of the workers.The dust diffuses with wind and causes serious environmental pollution.With the national attention to occupational health and environmental protection,dust control has become a hot spot in recent years.Chemical dust suppression technology is an important means of dust prevention and control,and has a broad prospect of development,but there are some drawbacks in the common chemical dust suppressants in the market at present.This paper aims at two main ways of dust suppression:controlling dust source to prevent dust raising and spray dust lowering,taking sodium alginate,a natural organic polymer,as the modified raw material,according to the required characteristics of dust suppressant,a new type of dust suppressant suitable for two kinds of operation was prepared by free radical polymerization.A phase change adhesive dust suppressant suitable for coal mine transportation and stowage is developed.The new dust suppressant can change from liquid to gel state in a short time under the condition of water loss.With this characteristic of the material,the liquid product is advantageous to wetting dust and permeating into the void,and the solid product can bond dust and cover the surface to catch a long-term suppression of dust effect.Specifically,caprolactam and acrylic acid are selected as the grafting monomers.Single factor experiments are conducted to determine the optimal conditions,i.e.,reaction temperature being 60?;the optimal mass ratio of sodium alginate to caprolactam being 1:4;the mass ratio of sodium alginate to acrylic acid being 1:2.67;the amount of initiator being 0.8 mol%of monomer;and the amount of cross-linking agent being 0.25 mol%of monomer.Each step of reaction takes 1 h.FTIR is employed to analyze the reaction process and the functional groups associated with the product.The structure and thermal stability of the product were analyzed by X-ray diffraction and thermogravimetric differential thermal scanning.Sedimentation experiment and contact angle measurement are conducted to test the wetting characteristics of the product.In accordance with the results of the contact angle measurement,0.1%of amphiprotic surfactant Dodecyl dimethyl betaine is added to the final product so as to further optimize the product's wetting effect on coal dust.Furthermore,an ultra-depth microscope and a scanning microscope are utilized to conduct microscopic analysis over the product,with the practical performance of the product tested as well.A kind of wetting-conglomeration dust suppressant was prepared for spray dust control,which not only has good wettability to coal dust,but also agglomerate dust together.Increase the rate of dust deposition the wind resistance of the dust deposited on the ground is improved so that the secondary dust is prevented at the same time.The optimum reaction conditions are as follows:the mass ratio of the main reactants to sodium alginate:caprolactam:acrylamide is 1:4:2,initiator/caprolactam is 0.8mol%.Dodecyl dimethyl betaine was added to the molecular chain by electrostatic adsorption under acidic conditions to improve the wettability of the materials.The wetting ability of the material to coal dust was tested by contact angle experiment and sedimentation experiment,and the dust lowering ability of the material was tested by the Doppler roadway simulation system.The wind resistance of the condensed dust was tested.The experimental results showed that the wetting-conglomeration dust suppressant had better dust control ability than the traditional surfactant,at the same time,The dust deposited on the ground also has the effect of preventing secondary dust raising.