Precautions for electrode paste used in carbide furnace
The electrode paste shall be stored in a special closed warehouse. The ground for storage shall be hardened with concrete, and the dust and sundries stacked on the ground shall be cleaned. Enterprises without conditions * suggest purchasing electrode paste packed in ton bags and covering it with tarpaulin after stacking on the clean ground to prevent dust and sundries from polluting the electrode paste, prevent the electrode paste from being exposed to the sun and change the performance of the electrode paste; Bulk electrode paste is not stored in the warehouse. It should be stacked in a clean place on the ground and covered with a tarpaulin.
During the transfer and addition of electrode paste, secondary pollution shall be prevented. All tools and appliances shall be clean. The measurement and addition of electrode paste column shall be in the charge of a specially assigned person. It is recommended that the measurement shall be no less than once per shift and the paste addition times shall be no less than twice per day, so as to maintain a relatively stable paste column height, prevent electrode paste shortage and suspension, reduce electrode accidents, and greatly benefit electrode sintering and consumption. After the electrode paste is added, the electrode cylinder of each phase shall be covered with a special cylinder cover to prevent dust and sundries from falling into the cylinder and causing electrode accidents.
Special personnel shall be responsible for the fabrication and butt joint of the electrode barrel. The butt joint shall be made in strict accordance with the accuracy and size required by the equipment and process, without any carelessness or carelessness. The welding seam shall be welded, without sand holes, and shall be polished and leveled. After the fabrication and butt joint, the welding seam shall be inspected with a flaw detector, and the special personnel shall be responsible for the acceptance, and the number of the electrode shall be numbered in order to track its quality. In order to prevent the welding seam of the seam welding machine from cracking, it is suggested that after the electrode barrel is fabricated, the arc plate and rib plate should be spot welded and reinforced every 100mm with an electric welding machine inside the electrode barrel.
The length of the working end of the electrode and the depth of entering the furnace shall be strictly controlled in accordance with the process operation requirements. After each shift, the measurement shall be carried out accurately. The measurement times of each phase of the electrode shall not be less than three times. If the deviation is large, the measurement shall be carried out several times. The average value of the three times with small deviation shall be taken as the length of the working end of the electrode. Only when the length of the working end of the electrode and the depth of entering the furnace are accurately mastered can the operation scheme of the shift be determined, and the pressing length Times, time interval and precautions during operation.
The electrode pressure release amount is to determine the pressure release length, times and time interval of the electrode according to the operation requirements of the process specification after measuring the length of the working end of the electrode. It is mainly necessary to make a scale on the electrode barrel in actual operation (the electrode barrel ribs on the upper edge of the clamping cylinder clamp are marked with a straight ruler, accurate to mm), Compare the accumulated pressure release amount (the times of electrode pressure release times the length of secondary pressure release) with the actual pressure release amount (the pressure release length read on the scale). The purpose of the comparison is to find out the symptom of electrode accident as soon as possible, deal with it in time and prevent the accident from expanding.
If the actual pressure release amount is more than the accumulated pressure release amount and the deviation is large, it proves that the electrode is sliding, the furnace shall be shut down as soon as possible to find out the reason for the electrode sliding, and the protective screen of the electrode shall be opened to check whether the conductive element is derailed, whether the clamping force of the element is sufficient, and other reasons. Hidden problems shall be eliminated. If the furnace is not shut down, electrode paste leakage or soft break may occur. If the actual pressure release amount is less than the accumulated pressure release amount and the deviation is large, which proves that the electrode can not be pressed down, the furnace shall be shut down for inspection to find out the reason for the pressure release. Open the protective screen and check whether the electrode is burnt or partially burnt, causing the iron sheet, rib fin and element of the electrode barrel to be burnt out, causing the electrode to be pressed down. If the furnace is not shut down in time, more conductive elements may be burnt out, or even the bottom ring pressure may fall off and cause water leakage, Resulting in large * accidents.
The maintenance of three-phase electrodes shall be carried out in strict accordance with the maintenance operation procedures, especially the clamping force of the insulation system, sealing system and conductive elements of the three-phase electrodes. The contact surface between the conductive elements and the ribs and fins of the electrode barrel shall be flat and smooth, without pulling grooves, and can reach the area of current transmission, so as to prevent the ribs and fins and elements from heating and causing local over burning of the electrodes, burning the ribs and elements and causing the electrodes to be pressed down; The insulation of each part of the three-phase electrode shall be qualified to prevent the electrode from being ignited and the electrode barrel from being burnt out, resulting in leakage or soft break; It may also generate local heating of the electrode, causing local over burning of the electrode; The sealing of three-phase electrodes shall be well done to prevent the flame from passing through the protective screen due to the fluctuation of furnace pressure, burning the insulation of the electrodes and causing local over burning of the electrodes.
Strengthen production patrol inspection, observe and think frequently, find the signs of electrode accidents, and deal with them in time to prevent the expansion of accidents. In the daily production management, the electric furnace equipment shall be inspected by patrol, and the signs of electrode accidents shall be found as early as possible from the raw material quality, batching, equipment (ignition, smoke and fire in the protective screen; temperature and pressure of circulating water, etc.) and operation. In terms of raw materials, timely check whether the raw and overburned content of lime exceeds the standard, which will affect the electrode consumption and pressure release speed. If the raw and overburned content is high and the electrode consumption is fast, the pressure release amount is bound to increase, which will easily lead to electrode leakage and soft break accidents.
Check whether the proportion of ingredients is accurate and whether the weighing of ingredients is accurate. If the proportion is low, the electrode consumption will be fast, the pressure will increase, and the electrode will be prone to paste and soft break; Too high proportion will cause high secondary current of electrode, fast sintering, slow consumption, less electrode pressure discharge and easy overburning. In case of fire, fire and smoke in the protective screen during patrol inspection, the furnace shall be shut down for inspection in time to prevent the electrode accident from expanding. If the water temperature of the conductive element is too high, the element may be derailed or the clamping force is insufficient.
Shut down the furnace for inspection in time to prevent the accident from expanding. In operation, if the working end of the electrode is short and the secondary current is low, it is necessary to rush to release the electrode for three consecutive shifts (the pressure release amount is more than 300mm), turn on the heating element for heating, * stop the furnace when the shift is handling the material surface, insert the electrode to the lower limit, and see the sintering condition of the electrode under the bottom ring, so as to know what to do, and prevent the occurrence of paste and soft break during the rush to release the electrode; If the length of the working end of the electrode is too long, and the pressure discharge capacity of three consecutive shifts is less than 60mm, all the electrode cooling air systems shall be opened to prevent the electrode from burning. If necessary, the electrode shall be increased, and the auxiliary lime shall be adjusted to speed up the electrode consumption, so as to increase the pressure discharge capacity of the electrode and prevent the electrode from burning.
When the calcium carbide furnace is shut down due to various factors, the electrode shall be protected according to the duration of shutdown, so as to effectively prevent various electrode accidents after power transmission. When the furnace is shut down for a short time (within 3h), the electrode shall be lowered to the lower limit, the furnace door shall be closed, the chimney valve shall be closed, and the electrode shall be insulated; When the furnace is shut down for a long time (more than 4h), open the furnace hole and drain the calcium carbide in the furnace. According to the duration of the furnace shutdown, press and discharge the electrode 60 ~ 200mm, lower the electrode to the lower limit, bury the electrode on the copper tile tip (bottom ring) with red material, press and discharge the electrode to oxidize, and the temperature difference between the upper and lower electrodes on the material surface is too large.
After the furnace temperature is reduced, close the cooling water of the copper tile and the large sleeve to prevent the temperature difference between the upper and lower electrodes of the copper tile from being too large, Hard breaking accident of electrode due to thermal stress after power transmission: the electrode moves once every 2h, first down and then up, 20mm up and down, to prevent the electrode from sticking and pulling off during power transmission; When the furnace is shut down for more than 5 days, the material level can be properly reduced by dry burning, the length of the working end of the electrode can be shortened, and the carbide in the furnace can be removed. After the furnace is shut down, the three-phase electrode can be pulled out of the material level, and it can be cooled evenly and naturally in the air. After the furnace temperature is reduced, the equipment can be shut down for circulating cooling water.