Study On Low-Temperature Soluble Starch-Based Solidifying Suppressants Controlling Coal Dust Pollution

The wind and vibration of vehicles would lead to the bulk materials losses, causing serious economic damage and dust pollution, in the transport and the piling of the bulk coal. The surface layer solidification technology is an effective method used in the preventing coal bulk losses and the dust suppression. The results of industrial applications in the Shenshuo special coal carriage railway shows the multi-hydroxyl polymer solidifying agent, which is based on the principle of surface permeation binding method, having the good solidification and the dust suppression property. However, the dissolving slowness of the raw material multi-hydroxyl polymer for solidifying agent production and the viscosity increase of the solidifying agent solution in the condition of low temperature in winter lead to pipeline and nozzle blockage, bring the adverse impact for the solidifying agent production and application. The aim of this dissertation is to solve the dissolving slowness of the raw material multi-hydroxyl polymer and the high viscosity of the solidifying agent solution in low temperature. The catalytic oxidation, dry heat processing, acid hot methods were used in the raw material starch chemical and non-crystal modification. The properties of particle morphology, crystal structure, gelatinization, and the dissolvability in low temperature of the modified starch were investigated. The main results are as follows:1. The degree of oxidation of starch is affected by the content of oxidant, the reaction temperature, reaction time and the catalyst. The oxidation could lead to the decrease of the degree of polymerization, the starch gelatinization temperature and the paste viscosity. The solution viscosity stability of the starch-based solidifying agent produced by catalytic oxidation has been improved. The effects of the application of the solidifying agent were good. It was observed that the oxidation processing could not change the starch crystal structure at the selected experimental conditions.2. The original starch emulsion was treated by ultrasonic. It is found the crystal structure of starch changes and the decreasing of the paste viscosity. The starch emulsion ultrasonic treatment has limited effects on the oxidation.3. The original starch dry heat treatment experiments were done at 170-230℃. The starch granule morphology and the crystal structure were changed, and the starch has high solubility in cold water. The viscosity stability of the dry heating modified starch cold water solution can be improved. The effects on the cold water solubility of moisture, temperature and time of heat treatment were investigated and the optimal conditions of cold water solubility were determined by the orthogonal experiment.4. The starch two steps modified tests combined with hydrochloric acid pretreatment and dry heating treatment were done. The results show that the modified starch treated by acid and dry heating methods would obtain better cold water solubility. Compared with the dry heating modified starch, the two steps modified starch required lower temperature, shorter time of dissolution. Effects on the cold water solubility of the concentration of hydrochloric acid, water content, heating temperature and time was obtained. The optimum conditions of cold water solubility were determined by the orthogonal experiment.