Research On Dusting Rules For Bulk-cargo Yard Of Iron Ore And Coal Terminal

As the rapid development of our domestic economy and modern port industries, the dustgenerated from various types of bulk cargo yard is more and more serious for environmentalpollution. Therefore, mastering the minerals’ dusting rules can provide scintific basis forgoverning this pollution question fundamentally.Results of the previous wind tunnel experiments will be summarized and analysed. Andin order to explore the relations that static dust dispersion of iron ore and coal varies withmoisture content and wind velocity, wind tunnel experiment will be carried out, includingSouth Africa iron ore, Australia iron ore, Brazil iron ore and bituminous coal. At the sametime, in-situ observations will be also carried out at the ore yard of the third iron ore terminalof Caofeidian Port Section, Tangshan Port. Main conclusions are as followings.(1) The influencing factors on dust dispersion are complex and variable, including windvelocity, temperature and humidity and other weather factors, particle size and surfacemoisture content and field operations factors. But the main factors are wind velocity andsurface moisture content.(2) The dispersion quantity is proportional to the power of the wind speed. Based on thewind tunnel experiments, it can be seen that under the natural moisture content, the dustdispersion of bituminous coal begins to increase when wind speed is larger than6m/s. Thedust dispersion of South Africa iron ore, Australia iron ore and Brazil iron ore are all smallwith the wind speed lower than9m/s, then the dust dispersion of Australia iron ore and Braziliron ore begin to increase when wind speed is larger than9m/s, but the dust dispersion ofSouth Africa iron ore is still small.(3) Results of the wind tunnel experiments and in-site observations both show that thedust dispersion decreases as the moisture content increases. When the the moisture contentincreases to a certain value, the dust dispersion begins to decrease slowly. The dust dispersionis proportional to the function of the negative exponent of the moisture content. The saturatedmoisture content of coal is about6%, Australia iron ore is about5%, Brazil iron ore is about2.5%, the saturated moisture content of South Africa iron ore is not obvious.(4) The hardening effect plays a significant role in the dusting of the iron ore and coalyard. When the surface has hardened after watering, the iron ore pile will not dust with thewind speed lower than12m/s and the coal pile will not dust with the wind speed lower than9m/s. (5) The data of site measurements indicates that in the case of low wind speed, the staticdust concentration is not that much related with wind velocity. It is also found that the dustcontent of the air is proportional to the function of the negative exponent of the moisturecontent. The regression results of the exponent are ranged between-2.64and-1.31. When themoisture content of the cargo is beyond3%, the dust content begins to decrease slowly.(6) Meteorological conditions also have important influence on the dusting of yard. Theyard cannot afford to dust when it rains or snows.