Research On Synthesis And Property Investigation Of Dust Suppressants For Construction Dust

Urban air pollution problem has become increasingly serious in our country, Dust has become the main factor of urban air pollution in our country. Especially in recent years, many large area haze outbreaks and, fog happened frequently, and larger and larger areas are involved in haze problems. Building construction dust is a cause for happening of the fog event, in order to solve the problem of haze, construction dust control is imminent. The research and practice have proved that chemical dust suppression is a relatively new, highly efficient method which can suppress the dust for long period of time. At home and abroad chemical dust suppression research object is mainly coal dust, mine dust, construction dust research is very uncommon. Therefore, dust suppression agent research has become an important research topic for solving the pollution caused by building construction dust.This thesis studied the basic characteristics of building construction dust, wettability of construction dust, dust suppression agent preparation and the verification of its performance. Dust suppression agent is made up of hygroscopic agent, coagulation agent and surfactant. With moisture content, the ratio of the dust on the screen and undersize soil quality, permeability as indicators, to determine the composition of dust suppression agent and its concentration range, the optimal dust suppression agent formula selected by orthogonal experiments, and the dust suppression performance is studied. The main research results and conclusions are as follows:(1) Particle size analysis of the the construction dust flowing through the 200 mesh sieve was conducted, the results indicate that the paricle size of construction dust was homogeneous, which can satisfy the following experimental requirements. By element analysis, it is concluded that elements of construction dust. Si in the soil dust was most, followed by Fe, Al. The content of Ca in concrete was the maximum, followed by Si, Mg. It is expected that traditional sprinkler dust suppression methods are difficult to restrain this kind of building construction dust. Through the true density determination of construction dust, soil dust of true density was 2.61 g/cm3, concrete dust of true density was 6.41 g/cm3.(2) Through the study of construction dust wettability, it is concluded that concrete dust is more difficult to be wetted than soil dust. The smaller the particle size, the more difficult it is to be wetted. Different surfactant could improve the wettability of construction dust, but the degree of it is different, among which CAPB works the best. Soil dust granularity fractal dimension and the contact angle has certain correlation, the correlation coefficient was 0.6032. Concrete dust granularity fractal dimension and the contact Angle of the correlation coefficient of 0.6014. Soil dust, concrete dust granularity fractal dimension was positively correlated with the contact angle, namely with the increase of contact angle, the granularity fractal dimension was increased.(3) The formula composition for construction dust suppression and concentration range were determined by high temperature evaporation resistance, abrasive resistance, permeability experiment and single factor experiment,which was 15%～25% of the calcium chloride,0.15%～0.25% of polyacrylamide,0.05%～0.15% of the coconut oil amide propyl betaine. The formula composition and the concentration range used for concrete dust was 15%～25% of calcium chloride,0.15%～0.25% sugar and,0.05%～0.15% of the T-20.(4) Through three levels and three factors orthogonal test, the optimal composition of dust suppression agent formula has been determined, the optimum formulation was 25%of calcium chloride,0.25% of polyacrylamide and 0.05% of coconut oil amide propyl betaine, dust suppression agent for concrete dust, the optimum formulation was 25% of calcium chloride,0.15% of sugar,0.15% of the T-20.(5) Moisture absorbing and releasing property and wind erosion resistance of soil dust suppression were better than that of ultrapure water, moisture content has been more than 9% in 10 days, the soil dust loss rate at 14 m/s was 0.23%. Moisture absorbing and releasing property and wind erosion resistance of concrete dust suppression were better than that of ultrapure water, moisture content has been more than 13% in 10 days, the loss rate of concrete dust at 14 m/s was 2.23%.