Introduction

Pulverized coal is the residue after complete combustion under specified conditions. It is formed by a series of complex reactions such as decomposition and combination of coal mine materials under certain conditions. It is a derivative of minerals in coal mine. When pulverized coal is heated in a restricted atmosphere, the yield of VOCs is called volatile matter, which is mainly composed of water, hydrocarbon oxides and hydrocarbons. However, physical adsorption water and carbon dioxide in pulverized coal are not included in the volatile matter. The volatile content of pulverized coal is one of the main indexes to judge the quality of pulverized coal. The high quality pulverized coal has a high volatile content. When casting, it is easy to form reductive gases in the cavity, and a large amount of bright carbon is precipitated. The casting with smooth surface can be obtained. Yi. As a result, the gas content of molding sand increases, the casting is liable to produce porosity, insufficient pouring and other defects, the volatile content should generally be controlled at 32-38%.

Pulverized coal Processing technology

Pulverized coal is a kind of irregular fine coal particles, which are milled by a coal mill. The particles are uniform in the range of 0.05-0.01 mm, and most of them are below 20-50 micron.  Vanguard pulverized coal mill has fully burned and high utilization rate. It has provided technical support for dozens of power plants. When the humidity of raw coal is lower than 15%,  Vanguard pulverized coal mill is used to grind raw coal into 200 meshes of fine powder. At the same time, the drying process is saved energy. The drying capacity of pulverized coal mill is mainly obtained from two aspects. One is the heat generated by friction between the mill and the material in operation. The other is that hot air can be introduced from the lower vent of the mill to accelerate the drying speed of pulverized coal. Vanguard pulverizer has a large output and obvious scale benefit. The cost of producing each ton of pulverized coal will be reduced with the increase of production. That is to say, the actual cost will be reduced. For power plants, metallurgical plants and other large-scale factories and mines, the annual coal consumption is tens of millions of tons.


Pulverized coal is added into green sand for cast iron to prevent sand sticking on the surface of the castings, improve the surface finish of the castings, reduce sand inclusion defects and improve the collapse function of the molding sand. For green ductile iron castings, it can also effectively prevent the formation of subcutaneous pores. Circular swirl burners can be used without preheating the air. The fineness of pulverized coal generally refers to the proportion of pulverized coal left on the screen during the test to the pulverized coal. The larger the fineness of the pulverized coal left on the screen, the thicker the pulverized coal will be. For example, pulverized coal fineness 1012R90 means that the probability of pulverized coal passing through a 90-micron pore sieve is 8890 and the failure rate is 1012. Generally speaking, increasing the fineness of pulverized coal is to make the pulverized coal finer, which will make the pulverized coal easier to ignite, burn completely, reduce the carbon content of fly ash, reduce the possibility of secondary combustion, at the same time, the flame center of the furnace is relatively lower, the furnace efficiency is relatively higher. However, increasing the power consumption of pulverized coal fineness pulverizing system will increase the wear and tear of pulverized coal parts in the mill, especially the steel ball mill. So for the power plant, the commissioning unit will give the reference value of coal quantity and current in the normal operation of the mill according to the grindability coefficient of the designed coal.

Application fields Through the deep processing, Pulverized coal can be widely used in the following industries.

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