The preparation requirements of the stemming is the most error of each material weighing <0.5%, each weight of 250Kg feed according to a certain feeding order, require mixing, the total mixing time is 8 ~ 10min; prepared the temperature of the stemming 50 ℃, the upper limit of the mixture particle size <3 mm, while less than 0.088mm more than 40%, moisture <4%. The role of various bulk
refractory materials in stemming is described below.
1, high bauxite
High bauxite particles and fines increase the fire resistance of stemming. The results of slag rotation erosion test show that the loss of stemming decreases with the increase of alumina content. Japan from the erosion of stemming mechanism found that the surface of the old aluminum high artillery mud although the electrical found SiC, alumina and other particles fall into the slag, but did not find the dissolution of alumina particles. In Japan, the use of electrically-conductive alumina is more common. Based on the national conditions in our country, it is appropriate to use super-rich or first-grade high-alumina bauxite which is rich in sources, inexpensive in bauxite, and capable of meeting the performance requirements.
2, silicon carbide
Carbide
refractory with high strength, resistance to hot metal and molten slag erosion, high thermal stress characteristics. The quality of silicon carbide should match the quality of the aggregate, from the cold and the use of requirements, SiC content of 50% and 70% of the two to choose from.
3, sericite
Sericite as a ceramic binder to make mud with low temperature strength. Due to the high content of alkali metal, the refractoriness drops, the quick-drying gunnable can be rapidly dried and hardened in a large temperature range (500-1650 ℃) to form a continuous strength, which can shorten the pumping time and win the maintenance of the iron mud Set and repair the main trench ditch time, reduce the glowing ditch lining of the mud gun baking. Sericite can also increase the rheological properties of mud, mud plasticity and lubrication properties are properly raised. Its dosage is less, require mixing evenly in the mud.
4, refractory clay
Refractory clay is an inorganic binder, forming a ceramic bond at high temperature, which makes the stemming at medium and high temperature (900 ~ 1440 ℃) to obtain sufficient firing strength, good plasticity at room temperature. On the grain size is extremely strict, more than 0.088mm into less than 5%, can increase the "slip" effect of stemming, mud can reduce the launch pressure.
5, expansion of materials
In the taphole, the stemming is a layered or massive structure, and stripping and shedding are one of the major causes of wastage. One of the measures to be taken may be to increase the tackiness of the old stemming and the new stemming by adding an expanding material . The amount of expansion agent added to increase the effect of swelling is significant. Production of gun mud line rate of change should be controlled within ± 0.5%, if the amount is too large, then generate more low melting point compounds, the loss becomes larger, and control the amount of added is necessary. The addition of a bulking agent improves the expansibility of the shotcrete, improves the adhesion between the new shotcrete and the old shotcrete, and improves durability.
6, Coke powder
Coke powder has high slag resistance and abrasion resistance, good air permeability, carbon products in the molten iron slag through and after the condensation process, are not bonded with the slag iron. Coke powder in the mixture of particle size requirements <l mm, too large will affect the plasticity. The higher the fixed carbon content the better, the water as low as possible. Coking powder in the coke generally from the blast furnace under the coke, the φ750 × 500 crusher broken <5 mm the following use.
7, asphalt
Softening temperature of 105 ~ 125 ℃ hard pitch, softening better plasticity, coke formation under high temperature carbon network structure, so that it has a high temperature strength stemming, volatile in the plug after the pores in the small Conducive to the drying mud stem. As the softening temperature of bitumen increases above 200 ° C, there are more components forming the high polymer in the bitumen which will enhance the coking performance of the bitumen. Hard asphalt mixing mill in the work of the flood (≤ 50 ℃) insoluble tar, help hand-cranked mud preparation and plasticity increase.
8, off-anthracene oil
Desiccant anthracene oil as binder and plasticizer Jing use, at room temperature (50 ℃) to shoot with a good relaxation and coke at high temperatures (1200 ~ 1500 ℃) coke ability to enhance the strength of mud.
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