How are the particles of raw materials classified? What is the role of the particles at all levels?

Since most of the clay minerals are present in less0.002mmMany of the properties of raw materials depend on the composition of clay minerals, so many countries in the world are more0.02mm,0.02~0.002mm, less0.002mmto grade.

Greater0.02mmThe particles are called sand grains, which have no bonding properties and mainly play a skeleton role in the process of drying and roasting. Its content affects the molding, drying and roasting properties of the green body. If the content of sand in the raw material is less, the molding is easier, but the drying is more difficult, and the roasting temperature is reduced; on the contrary, if the content of sand in the raw material is more, the molding is more difficult, but the drying is easier, and the roasting temperature is increased.

0.02~0.002mmThe particles are called dust particles. They have certain bonding properties, but they are loose after drying. During the molding and roasting process of the green body, on the one hand, they play a skeleton role, on the other hand, they play a filling role.

Less0.002mmThe particles are called clay particles, which have bonding properties and strong binding force after drying. It plays a filling role in the process of green body forming and baking, and produces plasticity with water. The clay cannot be too little or too much. Too much will cause difficulties in drying.

The three components of sand, dust and clay in the raw materials should have a suitable proportion to be used as raw materials for the manufacture of bricks and tiles.
What is the required range of particle composition of raw materials?

The range of particle composition requirements for the feedstock is shown.

  Particle composition range of raw materials

When<0.002mmof clay particles over25%It will show higher drying sensitivity, greater roasting shrinkage and higher product density.

How to adjust the plasticity of raw materials?

In order to overcome some shortcomings caused by raw materials in the production process, it is often necessary to increase or decrease its plasticity to meet the requirements of the technical conditions of the product.

（1) Ways to improve the plasticity of raw materials

In the production of sintered tiles, weathering, aging and batching methods are generally used to improve the plasticity of raw materials such as clay, shale and coal gangue.

①weathering

In order to destroy the natural structure of clay, shale and coal gangue, it is subjected to atmospheric action.--Weathering and freezing, especially in the use of difficult to loosen the colloidal clay and fat clay is more necessary. The purpose of this is to make the natural wet raw materials disintegrate (mainly volume change) and become fine particles under the repeated action of wind, rain, sun, snow, water absorption, drying, cold and heat, expansion and contraction. At the same time, many chemical and physical changes occur in the weathering process of raw materials, causing organic matter to decay, soluble salts to be leached, and sulfides to be oxidized. The original composition is changed and the technical performance of the raw material is improved.

The raw materials of some brick factories in China have been weathered and their performance has been significantly improved. For example, the raw materials of the first brick factory and the second brick factory in Changsha, Hunan Province are mountain soil. The newly excavated raw materials have coarse particles, low plasticity, difficult molding and poor quality of finished products. However, after one year of weathering, the particles become finer and the plasticity is greatly improved, thus fully meeting the production requirements. Therefore, both factories emphasize the use“alternate year soil”,"The next year" is a winter to spring after a freeze-thaw. It should be noted that the water present in the air will expand in volume after freezing.9%, Producing huge expansion stress, the effect of thinning the raw material particles is obvious.

However, weathering often makes the natural moisture content of raw materials greatly increased, easy to make crushing, crushing, screening equipment and silo and other sticky blocking.

②Aging

Aging is the broken, crushed and water after the raw materials stored in a closed room. in the water“splitting”Under the action of the raw materials to further loose, uniform water distribution, so that the content of organic and inorganic components of the colloid increased, so as to improve its plasticity, improve its technical performance.

Raw material of a certain factory3After the day aging, the dry strength of the brick blank is increased.50%.

• Refinement

Fine grinding of raw materials is good for improving plasticity. That is, no plastic raw materials, if fine grinding, can also obtain a certain degree of plasticity, but do so need to invest a larger cost.

• Ingredients

In actual production, high plasticity of raw materials are often mixed with low plasticity of raw materials, with plasticity of more appropriate raw materials.

When using this method, we should attach great importance to the uniformity of the distribution of two kinds of raw materials with different plasticity in the mixture, because the raw materials with low plasticity are easy to loosen in water than the raw materials with high plasticity.

If the mixing is not uniform, the green body after molding is not homogeneous, which will cause a lot of waste loss in the process of drying and firing.

⑤ Steam (hot water) heating

The mud is heated with steam (hot water) and formed by hot extrusion. After the steam (hot water) heats the mud, the moisture is evenly distributed in a short time and penetrates into the voids of the mud particles at a faster rate, thereby greatly improving the plasticity of the mud.

⑥ Vacuum treatment

The air contained in the mud will reduce its plasticity, causing blistering, delamination and cracking of the formed body. The use of vacuum extrusion molding can not only overcome the above defects, improve the plasticity of the clay, but also increase the strength and compactness of the green body.

（2) Ways to reduce the plasticity of raw materials

Generally, sand, slag and fly ash are mixed into raw materials.and clinker powder (e. g. waste brick powder)and other barren materials to reduce their plasticity. Especially after the internal combustion brick-burning method has been widely used, the best effect is the admixture of combustible components in the raw materials, which is both a lean agent and an internal fuel.

If sand is mixed, quartz sand is generally selected, and calcareous sand is not suitable, because the incorporation of calcareous sand will reduce the quality of bricks.

When mixing all kinds of barren materials into the raw materials, there is also the problem of whether the mixed materials are evenly distributed in the raw materials. Experience has proved that if the admixture is not evenly distributed in the raw material, it will bring bad consequences to the product, reduce the strength and serious.WhenCracks are generated.
What are the key points of operation and maintenance of double shaft mixer?

（14) Water and steam pipelines shall be unblocked without leakage.

（24) When starting up, the clutch shall be operated and feeding shall be started after the motor reaches the normal speed. When stopping, the feeding should be stopped first, then the clutch should be stopped, and then the motor should be turned off.

（34) When the equipment is stopped for a long time, the mud in the mixing box must be removed.

（44) Replace the lubricating oil in the reducer on schedule, and check the oil level of the oil pool frequently.

（54) Each rolling bearing shall be filled regularly.

（64) Regularly check the mixing tank and the mixing shaft, and repair or replace the worn lining plate and mixing blade in time.

The main points of operation of the roller machine?

（1) Before starting up, check whether the bolts in each part are loose, whether the lubricating oil at each lubricating point is sufficient, and whether the moving parts rotate flexibly,CleaningNearbyIrrelevantPeopleStaff.

（21) Start the equipment of the next process (such as belt conveyor, etc.) before starting the machine to avoid accumulation or blockage of materials.

（31) Empty machine start, waiting for rollCircleAfter the speed is normal, the material shall be fed, and the feeding speed shall be uniform. Prohibited in the rollCircleStart with load when there is material in the card, so as not to burn the motor.

（44) The raw material crushed by the roller shall reach the required fineness, for which the following measures can be taken.

①Control feed particle size, generally on the roll of the roll machineCircleDiameter, should not be less than the raw material particle size before crushing9Times.

②The moisture content of raw materials should not be too high, and should generally be controlled15%The following, otherwise easyTintedSticking rollCircleAffect the efficiency and effect of crushing.

③Feeding should be uniform, not suddenly feeding too much, the best raw materials can fall on the whole rollerCircleon the width to reduce the rollCircleUneven wear.

④Roll shall be maintainedCircleEstablished a smaller gap, if found to exceed, repair or replace the roller in timeCircle.

⑤If necessary, two or more roller machines (with belt conveyor) can be used in series,Raw materialTransition from coarse crushing to fine crushing to fully ensure the crushing quality.

（5) Avoid metal and other foreign matters falling into the machine,When the raw material enters the belt conveyor device of the roller machine, the iron remover is working.Once it happensMetal into the roll machineWhen the machine is stopped in time, it is strictly prohibited to pull things out in the rotating roller machine.

（6) oftenObservationWhether the temperature, vibration and sound of the motor and bearing are normal, and if any problem is found, stop the machine for inspection and treatment in time.

（71) The feeding shall be stopped before shutdown.counter rollThe machine can be shut down only after all the materials in the machine are emptied.
What are the key points of operation and maintenance of the extruder?

After the installation of the unused new extruder, a comprehensive inspection should be carried out first.

1. Check that all fasteners have been tightened.
2. Check that all lubrication points are filled with sufficient oil or grease.
3. The oil pool or reduction gearbox should be cleaned first, and check whether there are sundries, metal chips, etc. falling into the pool or box, and then injected into the pool or box according to the specified lubricating oil grade or quantity.
4. When the oil pump is used for forced lubrication of the transmission system of the extruder, check whether the rotation direction of the oil pump meets the specified requirements, and whether the oil pressure and circulation are good.
5. Check whether the rotation direction of the main motor and vacuum pump motor is correct.
6. Check eachClassWhether the tension of the belt is consistent.
7. Check whether the position of the adjusting nut of the clutch is appropriate, and whether the opening and closing and operation of the clutch are flexible. If a pneumatic clutch is used, check whether the air pressure of the air source, the air supply and the pressure reducing pressure through the pressure reducing valve meet the specified requirements.
8. Check whether the sealing of water pipe, steam pipe and vacuum chamber is good, and whether the valve opening and closing is flexible and reliable. （93) Check whether the electrical grounding of the whole equipment is good.

The following operations can be carried out only after the above inspection is completed and confirmed to be correct:

（1) Turn on the clutch and rotate the pulley by hand to make the extrusion spindle rotate4~5Turn to check whether there is any debris falling into the inside of the equipment and whether there is any blocking inside.

（24) For the vacuum extruder, use the same method to check the stirring part.

（3) After the above part is checked, open the clutch. to start the main motor. If the extruder adopts oil pump forced lubrication, the lubricating oil pump should be started first, and then the main motor should be started. After the main motor speed is normal, close the clutch and make the whole equipment idle1~2h.

（4) During the idle running, check whether each part of the machine is carrying normally, whether there is abnormal sound, whether there is abnormal temperature rise in each bearing part, and measure the no-load current of the main motor respectively. If any abnormal phenomenon is found, stop the machine immediately and eliminate it.

（5) In order to facilitate the discharge of the new extruder, a proper amount of water can be poured into the feeding place before adding the raw materials. For the vacuum extruder, the inspection door of the vacuum chamber can be opened at this time, and the feed can be started without starting the vacuum pump.

（6) When the raw material reaches the head and starts to extrude outward, open the clutch and stop feeding. Then install            Machine port, close the vacuum chamber inspection door.

（73) Start the vacuum pump. When the vacuum pump is of the water ring type, the water supply valve of the vacuum pump should be opened before starting the vacuum pump and adjusted to the specified flow rate.

（82) The clutch shall be closed, and the raw materials shall be evenly added from the feeding place to start the extrusion.

（9) through8hAfter the load is running, all fasteners should be checked for looseness to ensure vacuum and avoid equipment failure.

（10) During the above time, regularly measure the voltage and current value of the main motor; and check the temperature rise of each bearing part and electrical component; check whether the vacuum chamber is sealed well and record the vacuum degree; whether all moving parts and clutches are abnormal; whether the pressure and circulation of forced lubricating oil are good. If there is any abnormal phenomenon, stop the machine and eliminate it.

（11) After the extruder starts feeding100hThe amount of feed should not exceed the rated output.60%To ensure that the machine has enough running time.

（12) When the extruder needs to be shut down, the feeding should be stopped first, and the water supply and air supply valves of the stirring part of the vacuum extruder should be closed. When the machine port of the extruder does not continue to discharge, the clutch can be opened, the vacuum pump and the water supply valve of the vacuum pump can be closed, and then the main motor and the lubricating oil pump motor can be closed.

（134) When the extruder needs to be shut down for a long time, the raw materials in the mud cylinder, head and mouth shall be cleaned immediately after the shutdown.

Run an over-empty, heavy-duty test machine or an extruder in use as follows:

（1) Before starting the main motor, add lubricating oil to the parts that need to be added with lubricating oil, and check whether the fastening condition of the fasteners is good and whether the clutch is disengaged.

（2) Clean up the raw materials that have been dried up at the front end of the machine mouth.

（34) Start the main motor, and when the speed of the main motor reaches normal, the clutch can be closed. For the extruder with forced lubrication by oil pump, before starting the main motor, the oil pump motor should be started first, and then the main engine can be started.

（42) Feed the raw materials evenly from the feeding position of the extruder.

（54) Before the extruder mouth extrudes the mud strip, the equipment after the extruder shall be started separately for standby.

（6) When the extruder mouth starts to extrude mud strips, open the water supply valve of the water ring vacuum pump, start the vacuum pump, and the extrusion starts. Open and adjust the water supply and steam supply valves of the stirring part of the vacuum extruder as required.

（73) During shutdown, first stop the supply of raw materials and close the water and steam supply valves of the vacuum extruder. When the extruder port no longer continues to squeeze out mud strips, the clutch can be opened, and the vacuum pump, vacuum pump water supply valve, main motor and lubricating oil pump motor can be closed.

（84) When the extruder needs to be shut down for a long time, the mud in the mud cylinder, head and mouth shall be cleaned after shutdown. For short-term shutdown, the mud at the front end of the machine mouth should be protected to prevent excessive loss of mud water and hardening.

（9) Precautions:

9.1.It is strictly forbidden to start the main motor without opening the clutch;

9.2.It is forbidden to start the main motor when the lubricating oil pump motor is not started;

9.3.The closing of the clutch shall be stable and without impact. It is strictly forbidden to operate the clutch for a long time under the slipping state;

9.4.Feeding should be uniform, equipment overload operation is strictly prohibited;

9.5.It is forbidden to let hard objects such as metal blocks and pebbles enter the equipment with raw materials;

9.6.It is strictly forbidden to touch any parts in operation. It is strictly forbidden to use hands, feet or other tools to tamper with raw materials at the raw material entrance when the machine is running.

9.7.For the water ring vacuum pump, during operation, it should be ensured that the water has a certain flow through the vacuum pump, and the water temperature does not exceed15 ℃.

The regular maintenance of the extruder is the key to ensure the long-term normal operation of the extruder and extend its service life. Therefore, according to the use of the extruder, such as equipment quality, raw material properties and shifts, such as regular large, medium and minor repairs. Daily maintenance is also important. Regarding major, medium and minor repairs, it should depend on the specific conditions of the factory, and it is also related to the structure and quality of the equipment itself. It is difficult to make uniform regulations. But for routine maintenance, there are the following commonalities:

（13) All fasteners shall be inspected regularly and shall not be loose.

（24) All lubricating points shall be lubricated regularly according to the lubricating oil grade specified in the manual.

（34) The lubricating oil with centralized lubrication or oil pool lubrication shall be replaced according to the time and lubricating oil grade specified in the manual. Clean the oil filter, oil sump and oil tank, and regularly check whether the oil level meets the requirements.

（4) The V-belt should always maintain normal tension, and should be replaced after a certain period of use. When replacing, not only individual V-belts should be replaced, but the whole group should be replaced. The circumference of the new V-belt should be consistent to ensure that the tension degree of each V-belt is basically the same after tensioning.

（5) For mechanically coupled clutches, due to the wear of the friction plate during the engagement process, adjustments should be made in time to ensure that the engagement force of the friction clutch meets the requirements.

（62) When the wear of the screw reamer and mixing knife reaches the specified limit, they shall be repaired or replaced in time.

（74) When the machine parts are damaged due to the entry of foreign hard objects into the machine, the feeding port shall be used to find out the foreign hard objects and broken parts section by section. At the same time, other parts whose strength is weakened or deformed should be found and replaced completely.

（84) Other vulnerable parts of the machine shall be replaced regularly according to their wear degree to ensure the normal operation of the equipment.

（9) In the vacuum extruder, a filter is installed on the connecting pipe between the vacuum chamber and the vacuum pump. The filter should be cleaned regularly to avoid affecting the vacuum treatment of the mud.

What are the types of common iron remover?

The iron remover includes permanent magnet iron remover, electromagnetic iron remover and magnetic drum, etc., which are used to absorb ferromagnetic metals mixed in raw materials, protect the safe operation of equipment and improve product quality. The main products are briefly introduced below.

（1）RCYBSeries suspended permanent magnet iron remover: maintenance-free, long life, no energy consumption, simple installation, easy to use. Suitable for continuous work, less iron occasions.

（2）RCTSeries of permanent magnet drum: the internal use of high-performance strong permanent magnet material for excitation, with a strong magnetic field, long life, in addition to iron net, no energy consumption, suitable for continuous work, no fault and so on. Used in conjunction with the belt conveyor, it can replace the driving wheel or driven wheel with iron removal function, continuous work and automatic iron discharge.

（3）RCYB—TSeries of strong magnetic plate permanent magnet iron remover:

Using super rare earth alloy as magnetic system, computer simulation magnetic circuit design, strong magnetic field, large suction, no energy consumption, maintenance-free, reliable operation, clean iron removal.

（4）RCD（Y) Series electromagnetic (permanent magnet) self-unloading iron remover:

The interior adopts oil-cooled, self-cooled, air-cooled or permanent magnet structure, which is used for occasions with more iron content, automatic iron unloading and high efficiency.

（5）RCDESeries of oil-cooled electromagnet iron remover: the internal excitation coil adopts oil-immersed cooling, high-performance external heat pipe, fast heat dissipation and low temperature rise. It has the characteristics of dustproof, rainproof, corrosion resistance and long life.

（6）RCDBSeries of suspended electromagnetic iron remover: self-cooling fully enclosed structure, computer simulation magnetic circuit design, strong suction, deep magnetic penetrationDegreelarge, used in conveying materials, clear0.1~3.5kgFerromagnetic substances.

（7）GJTSeries metal detector: the use of novel digital phase shift and related metal detection technology, stable performance, high detection sensitivity, strong anti-interference ability, installed in the middle of the belt conveyor, the raw material mixed with the metal substance detection, automatic alarm and stop the belt conveyor operation or drive the relevant actuators.

Troubleshooting of Extruder

                      Troubleshooting of Extruder

Tunnel kiln roasting system, kiln carbyplay an important role?

Kiln car is an important part of tunnel kiln roasting system.

The lining brick on the kiln car surface is the sealed and movable kiln bottom of the tunnel kiln, which plays the role of protecting the metal kiln car and loading the billet stack to the kiln for roasting. Every time it passes through the kiln, it is heated and cooled once, and it is subjected to periodic temperature changes for a long time, and at the same time, it is required to carry out frequent loading and unloading work on its surface. Therefore, the kiln car lining brick is easy to loose and damage, serious or even hinder the normal operation of the kiln car.

Therefore, we should attach great importance to its material selection, lining brick structure design and masonry.

Because it is in an unstable heat transfer state in the kiln, the heat accumulated by the lining brick of the kiln car and the heat lost to the car through it are also changing with the change of time and position. The influence of accumulated heat: in the heating stage of the preheating zone and the firing zone, the temperature of the gas close to it is reduced due to the continuous heat absorption from the kiln, which aggravates the temperature difference between the top and bottom. The influence of heat loss: in the cooling stage of the cooling zone, the lining brick of the kiln car continuously dissipates heat into the kiln and under the car, thus reducing the temperature unevenness in this section. Weighing the pros and cons, if the lining brick has a large ability to accumulate heat and dissipate heat, it will extend the roasting time, reduce the output of the kiln, and increase fuel consumption. Therefore, it should be selected to accumulate heat capacity is small, that is, small volume density, small heat capacity, small thermal conductivity of lightweight insulation refractory materials. The selection of this kind of material not only helps to reduce the temperature difference between the upper and lower parts of the kiln, which is conducive to the uniform roasting of the products, but also reduces the heat dissipation to the car and reduces the temperature of the metal parts and the car.

The surface and surrounding of the lining brick of the kiln car, due to contact with high temperature and bear load, and to withstand periodic temperature changes, so these parts of the material should be able to withstand high temperature load and resistance to cold, heat and rapid change. Under the above conditions, materials with good thermal insulation performance should be used as far as possible.

Because the working environment of the lining brick of the kiln car has to withstand periodic temperature changes, the collision of loading and unloading and operation, it is easy to loosen and damage, and its structure and masonry are very important. Large displacement to both sides and front and rear is not allowed, otherwise the kiln wall will be stuck and the lining bricks of the front and rear cars will be stressed, causing accidents. Therefore, attention should be paid to the design of kiln car lining bricks: the lower part of the surrounding lining bricks should be stuck in the kiln car plate; The gaps of the upper, middle and lower bricks should be staggered, and there should be no straight joints (I .e. joints from the upper straight to the chassis of the car), and they should be stuck with each other. Adjacent bricks should bite each other to form a whole; One expansion joint shall be left in the longitudinal and transverse directions of the lining brick.

The lining brick masonry of kiln cars shall be carried out on the corrected flat track, so that each car has a uniform specification, and the masonry deviation shall be as small as possible.

A tunnel kiln is equipped with the largest number of kiln cars. The cost of the kiln car input accounts for about the total cost of the whole kiln.1/4Left and right. If not, the maintenance work after production is very heavy. Whether the kiln car is sturdy and durable not only affects the safe operation of the tunnel kiln, but also affects the product quality and production cost.

Kiln car frame materials are cast iron and steel two. The cast iron frame has the characteristics of high rigidity, small thermal deformation, oxidation resistance, corrosion resistance, sturdiness and durability. However, the quality of the frame is large, and it is necessary to have better casting process conditions to ensure its quality; the steel kiln car has the characteristics of convenient manufacturing and light weight. The frame of the kiln car is the main component of the force under the environment of large temperature change and uneven heating. It bears the load of the product and the extrusion force of the cart, and the force situation is more complicated. In order to make the kiln car run normally, we must strive to improve its working environment and strengthen the seal. The sealing of the kiln car has two parts: both sides are realized by inserting the sand sealing plate installed on the frame into the sand sealing groove; The end is realized by a tortuous structure (there are also fillers such as asbestos embedded at the end or mud smearing to fill the gap at the joint).
What are the main points of operation and maintenance of kiln car?

   （14) Before using the kiln car, it shall be checked one by one: whether the kiln car runs smoothly and flexibly; whether the seal is in good condition; whether all the wheels are in contact with the rail surface, and the wheels shall be lubricated.

   （22) When the manual yard car is used, it is necessary to prevent the collision and impact of other vehicles on the kiln car.

   （3) To prevent collision between kiln cars during operation.

   （41) When the kiln car is loaded and unloaded, it can only be operated after the rails are aligned.

   （54) The wheels shall be lubricated regularly.

   （64) Check the sand sealing plate frequently for distortion or deformation.

   （74) Regularly check the operation of the kiln car in the tunnel under the kiln, and repair the damaged sealing material in time.

   （83) Timely repair or replace the damaged refractory lining.