|Ceramic mug wholesale surface partial or total gray, brown or white impure, its cross-section also showed a dark brown. The reason is mainly carbon deposits inside the glaze, melt the glaze before, did not rule out the oxidation, the glaze after the carbon deposition in the molten glaze on. |
Resulting in carbon deposition in the glaze are mainly the following conditions: 1, chimney pumping power is too weak, too long warm-up with smoke, flame velocity is too slow; 2, full or full kiln car, the tray column by too tight, poor flow of the flame; 3, coal burning tunnel kiln, coal too fast because of the increase, the fire is clear and hardly ever burn, resulting in warm gas is too strong; 4, if the use of down-draft kiln, then the burning of coal is too thick, high ventilation, CO doctrinal result; 5, poor coal quality, the flame is short, such as pumping power is too strong, easy to make the tribal fire block, while the lower part of smoke is difficult, if coal is too good, high volatile matter, but also tends to atmosphere is difficult to transform; 6, oil fired tunnel kiln is too high content of carbon monoxide oxidation zone; 7, tunnel kiln high fire insulation stage, burn too fast, too small emergency air curtain opened, causing gas back; 8, oxidizing atmosphere inadequate, incomplete or oxidative decomposition too strong reducing atmosphere, melting completely glazed, not the end of reduction; 9, preheating zone temperature is too low; 10, glaze preparation, the raw material too much calcium or alkali powder grouting compound too much.
For the above, to solve the surface of ceramics smoked way should the following aspects: 1, strict control of the kiln atmosphere, attention to ventilation, the oxidation stage, oxidation was carried out to adequate and appropriate, restore should not be too early, too late; 2, grasp the green body of water into the kiln, with an appropriate increase in preheat temperature, dilute the appropriate box the main code, increase ventilation; 3, great atmosphere, open curtain, twice the amount of air and increase the amount of excess air, so that free carbon in the preheating zone to complete combustion; 4, the pressure to keep the kiln system stability and to prevent smoke backflow; 5, high thermal insulation stage reducing atmosphere can not be too thick, not with the increase of coal smoke, plus the former coal furnace flame should be blue slightly yellow; 6, the rational use of emergency air curtain, to be able to prevent the flue gas back to the principle of the glaze layer closed before the end of a strong reducing atmosphere; 7, coal firing should be based on coal, climate conditions determine the size of pumping power, if the combustion when high volatile coal, increase ventilation and accelerate the burn-off with smoke. If the low volatile coal, keep the fire a short time, reduced ventilation may be appropriate, so up and down the line. The order should be off the fire after the firing zone with a warm, warm up with a deposit to prevent smoke; 8, adjusting the content of calcium oxide in the glaze, it is appropriate; 9, grouting compound dielectric, can be mixed with humic acid and sodium water glass, to reduce the amount of alkali powder