Electric nickel furnace smelting (3)

(1) The structure of the fluidized roaster is put into the oven, and the furnace is opened and closed. 1) The structure of the fluidized roaster is shown in Figure 4. The furnace is a circular two-stage enlarged type, and the center of the furnace is exhausted, including a blanking tube. The overflow port, the bottom discharge port, the hood, the bellows, the air distribution cone, the air supply pipe and the furnace masonry are composed of several parts. The two-stage expansion is mainly to buffer the rising speed of the material in the furnace, reduce the content of the flue gas, and control the flow rate of the flue gas within a suitable range to facilitate the vortex dust collection.
The hood adopts a top side down-blowing type, which has the advantages of dispersing the air well, and because the air flows from the bottom to the top, the bottom material can be blown up to avoid deposition; and the material can be prevented from leaking into the bellows through the hood. Its structure is shown in Figure 5.

[next]

2) Oven For the new furnace, the baking before the furnace is very important. Whether the furnace is successful depends on the length of the furnace masonry, so the heating curve must be pressed in the oven (see Figure 6). get on.
During the oven process, the temperature indicated by the thermocouple should be recorded in time, and the expansion of the masonry and the change of the vault should be carefully observed, as well as other abnormal conditions. When some parts of the furnace fail and affect the normal temperature rise. Insulation should be carried out, and after the fault is eliminated, the temperature will continue to rise.
3) Opening and stopping the furnace When discussing the opening and closing of the fluidized furnace, it is necessary to distinguish between three concepts: 1 opening of the new furnace; 2 planning to open and stop the furnace; 3 opening and stopping the furnace during normal operation. The furnace of the dead furnace is turned on and off.
(1) Inspection before opening the furnace. Before the furnace is opened, all preparations should be done to thoroughly check whether the furnace body, instrument, air supply, smoke exhaust, feeding and discharging system have driving conditions. If there is any problem, organize relevant personnel to deal with it immediately.
1 furnace body. The furnace leader personally inspected whether the wind hood of the furnace is unobstructed. If there is any blockage, immediately pass it one by one. Whether the hoods are fixed or not, if loose, open the bellows and tighten them. Whether the oil road, wind road and steam road are unimpeded, whether the valve is flexible and not leaking (Note: suitable for the opening of the new furnace). Is the thermowell screw tightened and the gasket is properly seated. Whether the distributor can supply the charge 2 to the air supply system. Blowers with the length of the furnace employed to inspect positions, check whether they have to drive a high-pressure blast furnace conditions; emptying check valve and outlet valves (valve coal) whether air leakage. The engine should be debugged according to the meaning of each industry. L: First open the gas valve upper observation hole cover, then the electric brake plate is turned to the closing direction. When the distance from the gate plate to the sealing groove is 20mm, stop the electric motor and open the center of the manual rocker. Clutch, continue to close the gate manually until the manual rocker can not continue to run, then hand the manual rocker to rotate in the opposite direction for 5 to 9 laps. At this time, ask the electrician to adjust the closing limit switch, close the clutch, and use the electric test run several times. If it is normal, cover the cover hole and seal it, and the whole debugging process is completed.
3 exhaust system. The furnace worker cooperates with the dust collector to continue inspection: whether the flue, dust collection facility, ash hopper and ash pipe between the top of the furnace and the electric dust collection are blocked, whether the disc valve is flexible and easy to use; Whether the smoke exhauster has the driving condition, whether the instrument butterfly valve on the flue gas main pipeline and the inlet and outlet valves of the smoke exhauster are flexible; when using the cold state to check the air leakage point of the flue gas system, it is found that the air leakage point should be dealt with immediately. [next]
4 loading system. Cooperate with the posting system to check whether the equipment of the loading system is normal. The test should be carried out in a "reverse driving" mode to ensure that the equipment is normal, and at the same time, the transportation debris should not enter the furnace top silo; the furnace worker should have sufficient perceptual knowledge of the rice in the top of the furnace silo, and should grasp the moisture of the material. Physical properties such as particle size and chemical properties are to be counted in order to adopt appropriate operating methods and appropriate technical conditions.
5 discharge system. The furnace length should personally check whether the bottom discharge valve is flexible and easy to use, whether the switch is flexible, and whether the bottom material pipe and the overflow ready pipe are unobstructed.
6 instrument system. The length of the instrument and the instrumentation are checked in detail by the length of the furnace and the record is recorded. The blast test is carried out to see if the pressure gauge and the air flow meter are normal.
(2) Opening of the fluidized furnace 1 laying the bottom material. In the new vertical furnace, the fluidized furnace is generally made up of a mixture of calcined or raw concentrate and quartz sand of about 1:1. In the bottom material, too much powder or too high sulfur content, the heating process is easy to sinter, the bottom layer is too thin, and it is not easy to form a fluidized bed. The first paving thickness is 200-250mm. After the primer is laid, the blast test should be carried out. The purpose is not to form a preliminary fluidized bed on the air distribution plate and to check the fluidization in the furnace. When the blast is cold-tested, the surface of the material is flat after the wind is stopped, and the vortex is even, which proves that the air is evenly distributed and the fluidization is good, otherwise it will be treated until it is qualified.
2 ignition temperature rise. After the bottom material in the furnace is laid, the preparation work is completed, and the oven can be started to heat up. The purpose of the temperature rise is to prevent the cake from being formed, and the second bottom material is laid after 4 to 5 hours. When the total thickness of the layer reaches 400mm or more, the wind can be turned over and the concentrate is added. The temperature rises to the normal operating temperature and the furnace is turned into normal.
(3) Rapid furnace opening method When the fluidized furnace is planned to be opened after the furnace is shut down and the furnace is turned off, the rapid opening method is usually adopted. The condition of this method is that a fluidized furnace system must be in normal condition. Operation, at this time, the furnace to be opened can be put into the furnace by reference to the hot calcined sand produced by the normal operation furnace. After the local disease degree is 400-500mm, the blast air feed is transferred to normal, and it can be transferred to normal as soon as the high feed is turned on. The operation makes the opening of the furnace simple and time-saving, and the disadvantage is that the labor intensity is large and the working environment is bad.
(II) Normal process of fluidized roasting The normal operation of the fluidized furnace is mainly to adjust the ore volume with reference to the bed lamination drop and temperature. In the operation, it is necessary to master the overall situation of the operation of the furnace, and to develop the habit of comprehensive analysis of various indicators. The main points of operation are summarized as follows:
A serious: earnestly grasp the quality of raw materials;
Second look: look at the temperature operation, see the pressure operation;
Three Qin: diligent inspection, diligent contact, diligent adjustment;
Four inaccuracies: Do not allow positive pressure operation, do not allow large air volume and large volume operation, do not allow high temperature operation, and do not allow large hands and feet to adjust.
The process system of the roasting process should be strictly observed, otherwise a cycle of malignant substances will be formed, which will affect the normal operation of production. [next]
Below, the control of the main operating conditions is summarized as follows:
(1) Air volume. At present, the blast volume indication used in the fluidization furnace is to indicate that the flowmeter is installed on the blast pipe through the moving coil meter.
Under normal circumstances, the amount of air blow is fixed according to a certain amount of feed. Except for pressure fluctuations or voltage fluctuations, which may cause wind volume fluctuations to be adjusted in time, there is no need to adjust frequently after fixed air volume. However, when the furnace is newly opened or planned to be shut down, a larger air volume should be selected because of the flow state. When the layer of the layer is newly laid or stayed for a period of time, the porosity is much smaller than that of the layer of the layered layer, so the first blast is fluidized to overcome the maximum formed at this time. The pressure drop cannot reach the fluidized state, and local sintering occurs due to the occurrence of the channeling phenomenon, which causes the furnace to fail.
In addition, due to the relatively large size of dry concentrates, the daily wind volume (≥280Nm ³ /h) is adjusted in the same way as the bottom material, and it can often receive obvious effects in a short period of time. The disadvantage of this method is that the amount of soot increased significantly, increasing the burden cyclone dust collector, and serious pollution of the environment, cause some metal loss. Therefore, it cannot be used frequently.
(2) The fluidized bed is stable. Under the important conditions of fixed blast volume, the temperature of the fluidized bed is mainly determined by the uniformity of the feed and the stability of the chemical composition. The unevenness of the blanking not only affects the fluctuation of the fluidized bed temperature, but also most sensitively affects the fluctuation of the SO ₂ concentration of the furnace gas. Therefore, the uniformity of the middle material can be said to be the main link of the control operation. Especially for the semi-oxidized Baking calcination, the required calcination temperature is 650-750 ° C. Once the material breakage occurs, the temperature will quickly exceed the control range, resulting in a dead furnace. Therefore, in the operation, you should always pay attention to the blanking situation. In addition, if the high temperature operation in the normal production process, it is easy to soften and melt the low melting point material in the concentrate. If the material is suddenly broken, the material in the furnace is too late to be renewed, which is easy to cause sintering.
Changes in the chemical composition of the concentrate will also affect the temperature. The fluidized oxidative roasting process is an autothermal process, so in the case of a certain amount of blast, the sulfur content will also affect the temperature control. When the sulphur content in the concentrate is less than 18%, it is generally considered that the roasting process will not proceed. At this time, it is very easy to cause the cold bed to die. If there is a continuous decrease in the amount of material and the temperature continues to decrease or rise slowly during the operation, the amount of material should be maintained and carefully operated. When the sulfur content exceeds 25%, the flue gas temperature is too high, which affects the normal operation of the smoke exhauster. The current method is to add quartz to the concentrate, eliminate excess heat on the right, and reduce the electricity of the melting electricity diary. Single consumption.
In addition, the water fluctuation of the concentrate is large, making the temperature of the fluidized bed difficult to control stably.
(3) Pressure drop. It includes the resistance of the fluidized bed and the resistance of the air distribution plate. Pressure drop is an indispensable condition in operation and it can reflect whether the fluidized bed is in a normal state. Because the current hood type can not avoid the gradual blockage of the wind eye at all, the pressure rises with the gradual blockage of the wind eye, or the pressure of the bottom valve is not tight, causing fluctuations in the pressure drop, generally because the bottom tube is There is a pressure block rise caused by the blockage of the agglomerate, or the pressure of the bottom valve is not tight, and sometimes the pressure drops due to the clogging of the cyclone dust collector and the pressure rises. If the amount of feed is too large, the large particles in the furnace will increase, which will also cause pressure rise. These phenomena can be adjusted by discharging the bottom material and checking whether the overflow pipe is unblocked.
The significance of the pressure drop, in addition to marking the normality of the fluidized bed, can also indicate the degree of clogging of the hood, which can be reflected by the relationship between the gauge of the pressure drop and the thickness of the stationary layer in the furnace. Can be approximated as: [next]
Empty bed pressure drop (Pa) = pressure drop meter value (Pa) - furnace static layer thickness (mm)
The empty bed pressure drop can reflect the severity of the hood blockage. Therefore, the empty bed pressure drop should be measured as a reference for future operation at each new furnace opening, and a suitable pressure drop should be selected in the production to ensure the thickness of the static layer in the furnace. The thickness should be between 500 and 800 mm.
(4) Others. The top temperature is generally 30 to 50 ° C lower than the temperature of the fluidized bed. However, there are exceptions. If the amount of dust is too large, the temperature at the top of the furnace is almost equal to the temperature of the fluidized layer. Due to the objective factors of the existing process, when the furnace top temperature is above 700 °C, the inlet temperature of the smoke exhauster exceeds 400 °C, which will greatly increase the load of the smoke exhauster, causing frequent obstacles and affecting production.
In order to maintain good working conditions, the furnace pressure should not be positive pressure, but the use of excessive negative pressure will inhale cold air, which will affect the SO2 concentration and soot quality. Therefore, the pressure at the top of the furnace is maintained at -100 to +100 Pa. In order to ensure the normal operation of the smoke exhauster, try to reduce the temperature at the inlet of the flue gas to below °C, and periodically stop to refuel and clean the impeller.
In the production operation of the fluidized furnace, the positions should be closely coordinated. The belt transporter should keep abreast of the physical properties of the material, including moisture and grain size. It should always provide information through the furnace to master the appropriate operating conditions and ensure the normal operation of the fluidized furnace.
(3) Accident handling of fluidized roasting process (1) If the material is not added or other material is broken, the frying and feeding belt should be stopped immediately, then the wind should be stopped, the butterfly valve of the air supply and exhaust system should be closed, and the feeding system accident should be dealt with. After the treatment is completed, it is confirmed that the furnace can be newly opened when it is added.
(2) Suddenly stop the wind. If the high pressure blower suddenly stops and stops the wind, stop feeding immediately, and close all the valves of the air supply and exhaust system, and then restart the furnace after the high pressure blower returns to normal.
(3) The furnace temperature rises or falls. During normal operation, if the temperature rises too fast and exceeds the control range, it should be checked whether the feeding system is faulty and not fed. If the fault occurs, the furnace should be shut down immediately to deal with the accident. After the treatment is completed, the furnace is restarted. The furnace temperature should be gradually adjusted to within the control range. Don't be too hasty. If the temperature of the fluidized layer drops, after the bottom deposition is removed, it is necessary to check whether the amount of material is out of control. If it is out of control, it should be immediately shut down. After the high amount of material is cut, the furnace temperature is gradually returned to normal.
(4) The pressure rises or falls too fast. When the bellows pressure rises, large particle deposition should be considered. At the same time, referring to the bottom temperature of the fluidized layer, the bottom material should be used for adjustment. If the bellows pressure increases due to the roasting of the roasting, the furnace should be immediately shut down and the calcine should be discharged. .
If the bellows pressure drops too fast, consider the following factors:
1 Excessive material is used, which causes the material in the fluidized layer to decrease and the pressure to decrease. The bellows pressure indication does not swing. At this time, the air volume and the feed amount should be reduced, and gradually adjusted to normal according to the pressure condition.
2 After the bellows and orifice flowmeter, the pipeline leaks air, causing a sudden drop in pressure.
3 The condition in the fluidized layer is abnormal, and local perforation occurs, resulting in low pressure drop. [next]
4 The pressure tube is blocked, causing the pressure drop to drop, and should be handled by the instrument.
5 The wind drum does not enter the furnace and the pressure drop rises. It is caused by large-scale agglomeration on the hearth or severe clogging of the first-order vortex and secondary vortex. It should be randomly strained and immediately shut down.
If the pressure at the top of the furnace rises, it should be considered from the following aspects:
1 is too large than the normal operating value, should promptly check the cause of the treatment, and gradually adjust to the operating range 2 smoke exhaust pump reduction, should be timely contact with the smoke machine post, from the dust collection workshop, the smoke machine inlet butterfly valve, etc. Look for reasons and recover as soon as possible.
3 Dust collection and high smoke and blockage of the flue, or cracking and a large amount of air leakage, should promptly notify the dust collector to check.
4 handling of power outage accidents:
• When all the power outages of the instrument system cannot be judged, the furnace should be stopped immediately, and the instrumentation and electrician should be found to handle it.
• If the low-voltage system is completely powered off and the high-pressure blower is still working, when the valve cannot be fed and closed, the valve on the air supply and exhaust pipe should be closed manually, or the blower and the extension hood should be stopped immediately, etc. Continue to open the furnace after normal.
In short, in the production process, problems should be discovered in time, problems should be solved, experience should be accumulated, and operations should be continuously improved. It is good to apply the basic theoretical knowledge to practice in order to improve the level of production technology.
(IV) Rotary kiln roasting treatment of nickel concentrate, copper concentrate Rotary kiln is a thermal equipment for heat treatment of bulk or slurry materials. The rotary kiln is a hollow horizontal cylindrical device. The outer casing of the kiln is rolled with steel plate, slightly inclined to the horizontal plane (slope 2% to 6%), forming a low tail height, the material is inclined along the axial direction, and the kiln is Swing and thrust forward movement. The length and diameter of the rotary kiln are not strictly limited and are selected according to the process requirements.
Because the rotary kiln has the advantages of simple operation, strong adaptability to raw materials, high productivity, etc., according to the current raw materials of Jinchuan Company, the rotary kiln has the irreplaceable superiority of other roasting equipment in the treatment of miscellaneous materials. See Table 3 and Table 4 for the operating parameters of the nickel rotary kiln slag and copper rotary kiln.
In recent years, Jinchuan has achieved the following achievements in rotary kiln roasting:
1 frequency conversion technology application makes the equipment more energy efficient and easy to control.
2 The kiln head discharge and dust collection will be comprehensively improved, which greatly improves the working environment of the kiln head and recovers a large amount of valuable metals.
3 Computer offline technology in the application of the kiln, the operation from the experience operation to the intuitive, quantitative offline operation, to provide a favorable guarantee for product quality indicators and technical and economic indicators.
The application of the high-density polyethylene lining of the 4 disc not only ensures normal production, but also greatly improves the service life of the disc funnel.
5 The successful use of cross-suspension, double-chain plate and circular chain ring of nickel rotary kiln kiln tail chain reduces the growth speed of the kiln tail ring, prolongs the life of the chain and greatly prolongs the maintenance period. [next]

6 belt automatic core adjustment roller to reduce leakage. The application of heavy-duty anti-scratch cushioning prevents the belt from being scratched and improves the life of the belt.

The application of 7 heavy oil vortex grit sand backflushing filter ensures the quality of heavy oil entering the kiln.

8 crane vacuum contact cabinet transformation, greatly extending the crane maintenance cycle.

Coated Steel Pipe

Coated Steel Pipe,Steel Pipe With Pe Coating,Pe Coating For Steel Pipe,Inner Layer Coated Steel Pipe

SHANDONG DONGHONG PIPE INDUSTRY CO., LTD , https://www.donghongpipe.com