Compared with the traditional ordinary tunnel kiln, the new energy-saving and environment-friendly mobile rotary tunnel kiln are stacked at the bottom of the ring kiln at one time, and the relative movement required in the brick-making process is completed by the movement of the kiln body, so the kiln car and its supporting facilities are not required. The section of traditional tunnel kiln is generally 2.7-4.5m. The construction cost of tunnel kiln larger than this section is very high, while the section of circular rotary mobile tunnel kiln can reach more than 12M, and the construction cost is far lower than that of tunnel kiln.
Burning bricks requires coal or other fuels. How to maximize the thermal efficiency is the technical key of brick kiln design. The sintering temperature of brick is between 850 ° C and 1050 ° C. In order to save coal, the heat insulation effect of the kiln must be improved. The rotary tunnel kiln is stacked with refractory fiber cotton, which not only reduces the weight of the kiln body, reduces the thermal expansion and contraction stress of the kiln body, but also improves the thermal insulation performance of the kiln body. The kiln temperature is maintained for a long time, and the bricks consumed at one time increase in large area. The internal combustion heat energy can more effectively improve the kiln temperature and save fuel.
In ordinary tunnel kilns, in order to prevent high-temperature flue gas from flowing into the kiln car and burning out the wheels and bearings, it is also necessary to set up a gas source under the kiln car. In the whole heating system, the air supply pressure at the bottom and surface of the vehicle must be kept balanced, and the high temperature flue gas and cold air at the bottom of the vehicle must not rise to reduce the kiln temperature.
The bricks of the rotary tunnel kiln are directly stacked on the ground, without air supply under the vehicle, and the ground temperature is directly fully utilized. It is found that the aluminum silicate fiber blanket can still be calcined normally after 48 hours of coal and air shutdown in actual production, which is impossible for ordinary tunnel kilns. In the annular rotary tunnel kiln, when the firing temperature of bricks is reduced to room temperature, the heat released is enough to dry wet bricks of the same volume, so there is no need to build a hot air furnace, nor need to use the superheat roasting process to consume more coal to dry the heat.
In the heating system of the annular rotary tunnel kiln, dry air enters from the kiln tail and cools the sintered bricks through the cooling section to reduce the temperature of the sintered bricks at the outlet of the kiln tail to room temperature, that is, all the heat emitted by the sintered bricks is carried to the roasting section and drying section through the air entering the kiln for combustion support and drying. The energy saving of circular rotary tunnel kiln is its remarkable feature. Its reasonable process design, layout and simple logistics route also greatly reduce the energy consumption of the whole brick factory.The circular rotary tunnel kiln fully adopts mechanized operation and automatic digital control system. The temperature in the kiln is directly displayed on the display screen of the control system. There is no need to hire high-paying fire-watching teachers, which fundamentally eliminates brick-making and greatly increases production.
Step 1 : Buyers visiting some running brick plants to get basic knowledge for clay brick production
Step 2: Buyers study the market what kind of brick is popular
Step 3: Buyers make a plan for how many bricks per day to produce roughly
Step 4: Buyers or we help buyer check raw material whether suitable for making the popular bricks . If buyer wants to build full auto tunnel kiln plant .Buyer need to supply the soil test report.
Step 5: Buyers check what fuel is available like coal,gas,heavy oil,wood,rice husk ect in his place
Step 6: What is the buyer budget for brick machine and kiln roughly .
Step 7: Recommend the right offer or proposal based on buyer raw material brick size,daliy capacity,fuel, budget
Reason 1: No raw material analysis
According to our survey of 100 failed brick factories in the past, more than 80% of the brick factories did not do any analysis on their raw materials before building the factory. They just purchased brick machine and kiln equipment based on their feelings. In fact, the raw materials of each brick factory is more or less different. The selection of the machine should also consider its raw materials, brick type, kiln output, etc., which requires a systematic design.
Reason 2: Without professional design
More than 90% failed brick factories do not want to pay the factory design fees before they start the brick projects. In fact, a perfect process design process is an important guarantee for the success of a brick factory. The design cost of different brick factories is about 30,000~80,000 USD. Because of different raw materials and brick types, daily output, kiln width and length and building materials and kiln equipment used in the kiln will be different too. In order to attract business, many companies will not charge customers for design fees, because they are temporarily hiring some unqualified kiln workers to design for them. and these kiln workers do not actually have the ability to design. Sometimes they just buy a set of drawings from other companies and use them in different projects. How can such kiln workers guarantee the success of the project? Therefore, if the client wants to achieve the success of the project, he must be willing to spend money on those professional companies. Any kiln that is not professionally designed will generally fail
Reason 3: Does not have enough budget
Part of the reason for the failure of some projects is due to the limitation of funds. When selecting equipment,they just want to save money without considering the performance of the equipment. This leads to the fact that the brick factory is always stuck in the operation process, and the kiln does not have enough bricks to Production.
The following process is the right way to build one fully automatic clay brick plant :
Basic elements:
1. raw materials 2.water 3.electricity 4 land 5.fund
Step 1: Investigate the market and confirm the demand
To determine new plant production scale should refer to the local market conditions.First of all, we shall thoroughly investigate local brick and tile market conditions and grasp following situation:current market demand,actual production volume of existing companies, how big the market gap is,current selling price of brick and tile products and the demand and price trend.Besides,is there the same new brick factory to be built?What is the production scale?After mastering above conditions, the new plant can be determined.
Step 2: Confirm brick type
Formulate product production plan according to the condition of raw materials.When you build a new factory, you must have a clear understanding of the local production materials.After determining the dosing plan and selecting raw materials, we must determine the production plan and scale according to local market conditions. It is suitable for hollow brick or hole brick?Whether annual production scale should be 50 million or 80 million?
Step 3: Confirm the production process and equipment
Selected production process and equipment according to raw materials.Clarify your raw material properties before starting new plant.Please have experienced technical staff to plan the production route and conduct selection or design production equipment.Not all equipment can adapt to your raw materials.
Step 4: Infrastructure construction
After determining production scale, it is possible to determine area, process direction, equipment layout of production plant and the location of living area according to the size of production volume.Plan plant elevation based on local geological, hydrological and meteorological conditions.]Arrange various production workshops according to the wind direction.To determine the mode of production, shall it be labor-intensive companies or technology-intensive enterprises,requires whole careful plan and design by technicians based on the results of technical and economic analysis.
1. Civil work: including Chenhuachi, workshops, doors, windows, and roofs of aging workshop.Meet installation requirements of reversible spreaders, multi-bucket excavators and conveyor belts.At the same time, water supply and drainage and heating are completed.
2. Aging workshop:The crushing workshop completes all civil construction tasks inside and outside the crushing room and feeding room.Complete the plant closure work.Meet installation requirements of feeder boxes, belts, crushers, vibrating screens, back-feed belts, and aging conveyor belts etc.
3. Molding workshop:including the feeding box, mixer, clay machine, extruder, cutting and transportation construction, as well as the kiln base after pouring belt,top car machine, tractor, kiln channel pavement, cushion and other construction.
4. The civil construction scope for air compressor stations, plumbing, substations, fire pump rooms, etc. includes drying kiln, roasting kiln, ferry car,hydraulic pusher,return tractor,traction machine, winch, tidal fan, blower, kiln cooling fan,pipeline , heat exchanger,kiln car production, track and so on.
Step 5:Preparation before production
1. organization construction
2. Make plans and regulations
3. Maintain and add equipment
4. Clean up the existing dry site and drying supplies
5. Maintain kiln
6. Maintain electrical equipment
7. Prepare sufficient fuel
8. Preparation of auxiliary items for production
9. Construct road and drainage
10. Prepare raw materials in advance
11. Ensure safety precautions
12. Run a test
13. Prepare spare parts
Entry arrangement for overall equipment:
1. box feeder,crusher,roller screen,mixer,belt,precipitator etc in crushing workshop
2. Multi-bucket excavator, reversible spreader
3. Box feeder , mixer, vacuum extruder, cutting and transporting equipments
4. Ferry car,hydraulic pusher,return tractor and hoist.
A brick is building material used to make walls, pavements and other elements in masonry construction. Traditionally, the term brick referred to a unit composed of clay, but it is now used to denote any rectangular units laid in mortar. A brick can be composed of clay-bearing soil, sand, and lime, or concrete materials. Bricks are produced in numerous classes, types, materials, and sizes which vary with region and time period, and are produced in bulk quantities. Two basic categories of bricks are fired and non-fired bricks.
Block is a similar term referring to a rectangular building unit composed of similar materials, but is usually larger than a brick. Lightweight bricks (also called lightweight blocks) are made from expanded clay aggregate.
Fired bricks are one of the longest-lasting and strongest building materials, sometimes referred to as artificial stone, and have been used since circa 5000 BC. Air-dried bricks, also known as mudbricks, have a history older than fired bricks, and have an additional ingredient of a mechanical binder such as straw.
Bricks are laid in courses and numerous patterns known as bonds, collectively known as brickwork, and may be laid in various kinds of mortar to hold the bricks together to make a durable structure
https://en.wikipedia.org/wiki/Brick
The production process of sintered bricks is generally composed of four parts: raw material preparation, blank body forming, wet blank drying, and finished product firing.After raw materials are excavated, some can be processed by adding water, stirring and grinding equipment,while others will not work.Raw materials,such as mountain soil, coal gangue and shale,are to be broken and finely chopped, then followed by water mixing and grinding.The choice and preparation of raw materials directly affect the quality of the finished product.As the saying goes, raw materials are fundamental to making sintered bricks,showing the importance of the raw materials preparation and raw materials.
After the selected brick raw materials are processed, they enter the molding workshop for molding.Blank forming method basically uses plastic extrusion molding in China.There are three methods for plastic extrusion. That is plastic extrusion molding,semi-hard plastic extrusion molding and hard plastic extrusion molding.
These three extrusion methods are based on the difference in the moisture content of the molding.When the moisture content more than 16%,wet billet molding is plastic extrusion molding. When the moisture content equals 14-16%, it’s semi-hard plastic extrusion molding. When the moisture content equals 12-14% ,it’s hard plastic extrusion molding.Blank forming includes: feeding material , mixing,adding water and grinding equipment processing before raw materials entering the molding shop not brick extruding machine.After passing through the molding brick machine, the qualified mud and wet billet are formed.Forming process should fulfill the requirement of the shape and structure.Forming is the foundation of the brick making process.The quality of the formed body is directly related to the appearance quality of the finished tile.
After the wet billets formed from the molding plant, they need to be dried by dehydration.In the production process of sintered bricks, there are two ways of drying wet blank: natural drying and artificial drying.
The natural drying is to place the wet billet on the billet stalk in the natural drying place,manually invert the code and use the atmosphere to wet the cold billet into a dry billet.Artificial drying is to use equipped artificial drying chamber to dry wet billet.The artificial drying room is divided into three types: large-section tunnel drying room, small-section tunnel drying room and chamber drying room.Whichever type is adopted, it is manually or mechanically placing wet billet on a drying truck,then put it into drying chamber.The heat medium in the drying chamber generally comes from the waste heat of the sintering kiln or the hot blast stove.Whichever drying method is adopted, it must be ensured that the blank will not be deformed or chapped during the drying process.If the wet billet can’t guarantee the appearance quality of the product during drying, it will cause high reject rate, falling output,increasing cost of the finished brick, which are definitely harmful to company economic efficiency.This shows the importance of drying wet billet in brick making process.
If the residual moisture rate after drying is less than 6%,the wet billet could be fired in the baking kiln.Hoffman kiln and tunnel kiln are normally used for roasting.When using Hoffman kiln, the brick code is manually placed in the kiln and the fire is roasted in the kiln.When using tunnel kiln,the brick code is manually or mechanically placed in the kiln cart.The kiln car enters kiln head and exits from the kiln tail. The brick blanks on the kiln car are roasted into bricks.The roasting flame in the kiln doesn’t move just the kiln cart.Whether using Hoffman kiln or tunnel kiln,this two conditions must be followed:1.never use underfire to produce unburnt brick.2.never use big fire to produce coke brick.It is often said that roasting is the key of the brick making process,which explains the importance of roasting in the brick making process.
Sintered brick process is composed of four parts.To sum up,it is said that the raw material is fundamental,molding is the basis,drying is ensure and roasting is the key. These four parts are interdependent.
Type |
Raw material |
Forming method |
Burned or not |
Brick type |
Clay、shale、coal gangue、slag、fly ash etc. |
Screw extrusion |
Burned |
Solid brick、Hollow brick、Multi-hole brick |
|
Soil、cement etc. |
Molding press |
No |
Solid brick、Multi-hole brick(2-3 holes)、Paver |
|
Cement、fly ash、slag、sand etc. |
Molding press |
No |
Solid brick、Hollow brick、Multi-hole brick、Paver、Curbstone |
|
|
|
clay brick | cement brick | interlock brick |
--1--- Buildings constructed with high-performance thermal insulation blocks can guarantee long-term economic advantages, long-term energy saving, and minimum maintenance costs during the service life.
---2---
Houses built with high-performance thermal insulation blocks have a long-term use value due to the very good durability of sintered materials, which can ensure that the investment can serve several generations. High-quality sintered brick masonry buildings can be sold at high prices.
---3---
The comfort of the living room is good. A house built with high-performance thermal insulation blocks can make the interior feel very comfortable. Because of the countless micropores in the sintered product, it can adapt to the change of indoor and outdoor humidity very well, so it can ensure that it has a very good storage capacity for water vapor and a very good release capacity. The sintered building materials have a warm-colored surface, which can buffer the changes in humidity and heat. The sintered building materials have very few harmful substances, which can ensure a healthy indoor environment and make people feel comfortable indoors.
---4---
Due to the pores formed when the sintered block is formed and a large number of microporous structures are left during sintering, the external wall constructed with it has excellent thermal insulation performance.
---5---
Since the sintered blocks can naturally absorb the energy of the sun, it can also absorb and store the heat generated in the room. The heat absorbed by the wall can be released into the room through the wall, but the release time is longer-the temperature delay time is long. In winter, this process of absorbing and releasing heat balances the fluctuation of indoor temperature, which saves energy for heating, and at the same time feels comfortable and warm indoors, and cool in summer.
---6---
Sintered blocks have ideal characteristics of absorbing and releasing moisture. It absorbs indoor moisture and releases moisture at the same rate as the block. The surface of the wall can be kept relatively dry in any season, which ensures the comfort of the indoor environment.
The sintered wall roofing material product is a product with a microporous system. Its moisture conduction function can adjust the humidity in the building, and the speed of moisture absorption and drainage is equal. The water absorption and drainage speed of bricks are higher than other building materials 10 The structural strength of the building is not affected in any way when water is absorbed and discharged. This alone can improve the living environment and make the human body feel comfortable. Moreover, the equilibrium moisture content of the brick masonry is very low, which enhances the heat insulation effect of the masonry.
The equilibrium moisture in the wall of a building refers to the balance between the moisture left on the wall after drying and the moisture in the atmosphere. For brick masonry, this equilibrium moisture only accounts for 0.3% to 0.7% of its volume. Compared with other building materials, this is a very low value. It is precisely because of this very low value that it provides a comfortable and healthy environment for people living in brick buildings. The water absorption speed and drainage speed of the brick masonry are almost the same, so it can adjust the humidity of the small environment in the living room, which is often referred to as the \"breathing\" effect. In addition, the very low equilibrium moisture content of brick masonry is also very important for energy saving.
Because of the increase in water content of building materials, its thermal insulation performance will deteriorate (or deteriorate). In this sense, the brick itself is a very good \"insulation body\", and it can also effectively protect the thermal insulation material layer compounded with sintered bricks or blocks, and will not reduce its thermal insulation performance due to moisture absorption. performance. The proper drying time for the main body of a newly-built building means that after the construction of a building in a specific area, it can be dried at an appropriate time without using a special heating method. Generally speaking, each type of masonry structure absorbs water directly from the mortar during construction.
The criterion here is: the speed at which the absorbed water is discharged from the material. Because brick buildings have a slight vapor diffusion resistance, they dry very quickly and the average drying cycle is very short, which provides time for the early delivery and move-in of new buildings. The drying cycle of the wall depends on different regions and seasons. And this drying process of some building materials often lasts for several years.
Therefore, the drying time should be specified in the design according to the selected materials and different regions. Our country is not sufficient for this time, often in order to shorten the delivery period, move in early, resulting in moldy and deterioration of the decorative materials; in addition, due to improper selection of materials, the materials are often dehydrated after the residents move in, causing problems such as wall cracks.
---7---
Thermal comfort is very important, that is, the temperature parameter of the indoor wall surface of the building. When the surface temperature is much lower or higher than the indoor air temperature, it causes a very uncomfortable feeling. The sintered block has very good thermal insulation performance, and the outer wall built with it ensures a higher temperature of the indoor wall, so it has a very superior thermal comfort.
In summer, and vice versa. The \"secret\" of good thermal insulation performance lies in the microporous structure, where there is air in the small micropores. Add micropore formers during the preparation of raw materials, such as sawdust. After being shaped and dried, it is fired at a high temperature of about 1000℃. The sawdust burns and volatilizes, leaving countless small and air-containing micropores, which greatly improves heat preservation. Thermal insulation performance. The porosity of the sintered block, combined with the well-designed hole geometry, has very good thermal insulation performance, which can greatly reduce the heat loss through the external wall.
The sintered block can be used as a heat storage body, and the sintered block wall can naturally absorb the heat from the sun and can store the heat from the room. When needed, the indoor heat it absorbs can then be transferred back to the supply room. This kind of performance can make the room feel comfortable. The characteristic becomes \"phase shift\". The house of sintered blocks does not cool too quickly in winter, and it can keep the interior cool in summer. Sintered building materials have relatively low equilibrium moisture content and fast drying characteristics. Therefore, the walls of sintered building materials can quickly form the best insulation layer, thereby saving energy consumption for heating and air conditioning.
---8---
Excellent fire resistance-sintered building materials products will not burn, they are sintered products, so they have \"immunity\" against fire. Sintered building materials will not produce any harmful gases in the event of a fire. When the thickness of the wall is 8cm or thicker, the wall can reach a fire rating of F90. That is to say, in the event of a fire, people have 90 minutes to escape or transfer property. When a fire occurs, the harm to the human body is generally not the direct impact of the fire, but the smoke generated by the combustion of flammable building materials and decoration materials. But sintered blocks are sintered at high temperature, they do not burn, and will not release any harmful gases when a fire occurs.
---9---
Sound insulation performance is good. Sintered hollow (porous) blocks are sound insulation. Buildings need to have sound insulation measures to prevent noise from the outside and noise from neighbors. The noise generated by ventilation, impact and structure should be reduced to a level that does not affect others. The walls and floors made of sintered blocks ensure a quiet living environment and prevent noise from outside and inside the building. The outer wall of sintered blocks has excellent sound insulation performance. For places with special uses, there are also special sound insulation hollow blocks.
---10---
High structural strength. Sintered blocks are safe houses. Sintered blocks have a variety of different compressive strengths, and effective quality control and monitoring in production. For builders and architects, sintered blocks are safe and reliable.
---11---
Good seismic safety: For earthquake-resistant areas, sintered blocks for earthquake resistance have been specially developed. The wall built with seismic blocks shows that its seismic capacity is ten times higher than that of conventional blocks. Therefore, in earthquake areas, seismic blocks can be used to build safe, economical and durable buildings. In high-earthquake areas, it is entirely possible to use sintered blocks to build walls. Because of every other building material, the wall structure and building structure selected in the earthquake-prone area must also meet the seismic requirements. Sintered blocks have high mechanical strength, and have very good bonding characteristics with mortar, so it can effectively improve the seismic performance of buildings.
Economical: Sintered blocks have the greatest quality and value retention. Although the choice of wall materials has little effect on the total cost of the building, it determines the quality of the building. Houses built with sintered blocks are economical, safe, and can maintain and increase in value, because the durability of sintered blocks is unparalleled. The use of sintered blocks can shorten the construction period of the building, significantly reduce the amount of mortar, and the maintenance cost during the use period is very low. The high thermal insulation performance and air tightness of sintered blocks greatly reduce energy consumption. The long-term service life can be preserved and increased in value, and houses can be built for several generations.
In brick tile machine, the parts where the soil goes through is easy to be worn out .If we do not repair
the easy wear parts timely, the production will be influeced.
But what materials we should use to repair the easy wear parts ?
Usually
we use A3 Carbon steel to repair the extruder auger and liner, double
shaft mixer blades etc.
However, we find that after the Carbon steel can
not fit for long time wear resistant requirment. After
some time , we
find that if we adopt Fe-Cr-B wear - resistant electrode to repair
auger,we get can
1.8 million green bricks while previously we only got 400,000 green bricks by carbom steel one time
repairing. The auger service life extends 4.5 times. The 2/3 repairing material cost is saved.
It is proved by pratice that adopting wear resistant material to repair easy wear parts is an effective
way to improve efficiency,extend working life and reduce cost .
HRC
Usage
Diameter
(mm)
Length
(mm)
Current
(A)
Note
≥65
Auger,mixer blades,rollers of roller crusher,blower blades
3.2
350
130~160
first time build-up welding
for 500 model extruder need 6 kg,thickness 2~3 mm,one time repairing need 1.5~2 Kg,
capacity 4million to 6
million green bricks
4
400
180~230
≥50
Hammer of hammer crusher
3.2
350
130~160
4
400
180~230
The plasticity expressing in China’s brick and tile industry is now proposed by the Swedish A. Aterberg in 1911.Plasticity index is expressed as the range of water content when the clay is in a plastic state,whose value is equal to the difference between flow limit and plastic limit.Flow limit, also known as liquid limit, is water amount that clay enters a flowing state.Plastic limit is water amount that clay can be rolled into 3mm diameter.
According to this method, the plasticity index is used to classify clay as: high plasticity clay >15%; medium plasticity clay 7%-15%; low plasticity clay<7%.
This method has been widely used for many years in the fields of soil science and engineering geology.Although China's brick and tile industry has been using it for many years, it is only for soft and dispersed clay raw materials.For coal gangue, shale, etc., which rely on reducing particle size to obtain plasticity, there is a great deal of deviation in using this method.For example, the plasticity of raw materials such as coal gangue and shale depends on crushing to reduce the particle size to a certain degree, adding water to the particles after decomposing (aging), and it is changeable during processing.If the hard clayey shale or coal gangue rich in illite is ground to a sufficiently fine degree (such as cement fineness),the plasticity index may reach a pretty high level.And formed moisture content and drying shrinkage may be larger than common clay materials, which totally differ from common brick clay.
The plasticity index of common brick clay is relatively stable.In terms of this type of material, which depends on crushing process reducing particle size to obtain plasticity, its plasticity index is variable during processing.For example, when a certain coal gangue is crushed below 0.9 mm in the laboratory, according to geotechnical test method, the plasticity index is measured as only 7.2%.However, after adding 40% of excessively fired vermiculite (essentially no plasticity),then adding water, aging, and crushing on the roller, vacuum extrusion,plasticity index of the small sample actually reached 10.5%.For example, when other shales were crushed to less 0.9 mm, the plasticity index is measured as 8.4% according to geotechnical test method.However, after adding 40% (by weight) of fly ash,then mixing with water, aging, and crushing,plasticity index of the small sample extruded by the vacuum extruder reached 9.5%.This is still the result after revalidation according to the geotechnical test method,which fully demonstrates that the current geotechnical test method used in the brick and tile industry can’t correctly reflect the characteristics of raw materials such as coal gangue and shale during processing and forming.In order to further prove the fact that raw materials such as shale or coal gangue relys on reducing the particles size to obtain plasticity, the hard shale in a place near Shijiazhuang was crushed into two groups in the laboratory.One group all can pass 0.9 mm sieve; the other can all pass 0.5 mm sieve.However, the shale of the same mineral composition differs greatly in its plasticity index only due to its different grain sizes, one being 4.8% (0.9 mm) and the other being 8.9% (0.5 mm).In order to further verify this phenomenon, this two groups were blended together in different proportions to determine their plasticity index, drying line shrinkage rate and drying sensitivity index. The results are shown in the following table.
Blending ratio % Weight |
Flow limit% |
Plastic limit% |
Plasticity index% |
Drying sensitivity index |
Dry linear shrinkage |
||
0.5㎜ |
0.9㎜ |
|
|||||
10 |
90 |
17.3 |
12.3 |
5.0 |
0.47 |
1.94 |
|
20 |
80 |
17.6 |
11.7 |
5.9 |
0.68 |
2.06 |
|
30 |
70 |
18.3 |
12.1 |
6.2 |
0.66 |
2.12 |
|
40 |
60 |
19.0 |
12.7 |
6.3 |
0.76 |
2.32 |
|
50 |
50 |
19.8 |
13.4 |
6.4 |
0.87 |
2.34 |
|
60 |
40 |
19.0 |
11.8 |
7.2 |
0.85 |
2.66 |
From the above table, it can be clearly seen that the plasticity index, dryness sensitivity index, and dry linear shrinkage of the mixture tend to increase with the increase of the particle composition below 0.5 mm in the mixture.This fully shows that the use of geotechnical test method can not fully evaluate the properties of plastic materials such as shale and coal gangue that rely on reducing particle size.From the above analysis, the plasticity degree has a great relationship with the particle size of clay minerals.
For example, assuming that the type and total amount of clay minerals contained in a kind of clay are exactly the same as that in a certain type of shale, plasticity index measured by the geotechnical test method is much higher than shale,because dispersed clay mineral particles in the clay are uniform and small.If the shale is fully crushed, so that the clay minerals in the shale reach a finely dispersed state like the clay mineral particles contained in the clay, it is possible that the plasticity index measured by the geotechnical test method will be the same as that of the clay.However, it can’t be achieved in actual production,causing a great plasticity fluctuation during processing raw materials such as coal gangue and shale.Which method should be used to describe and compare the plasticity of these raw materials?
First of all, it is necessary to limit the particle size composition of this kind raw materials after crushing.According to the practice and research of bricks and tiles produced by shale in USA for many years, shale crushing can provide 0.053 mm (270 mesh) or more particles.And it is thought that shale crushed should have three levels of particle grading:(1)The decorative coarse grain should occupy 0-3% (the grain size is generally 1.2-2.4 mm, sometimes it can reach 9.5 mm. It can be used without coarse grain decoration);(2)Filled granules should occupy: 20-65% (1.2-0.3 mm, this granules part is to limit the excessive shrinkage, cracks and deformation of the granules);(3)Plastic particles should account for 35-50% (below 0.053)
This indicates the minimum of plastic particles less than 0.053 mm after comminution,whether it is shale or coal gangue. The amount of particles smaller than 1 mm, or less than 0.05 mm, which was previously proposed in the design, is a very inaccurate method.If the gangue is completely crushed into 1 mm diameter pellets, it is possible that this material will not have the plasticity for forming.Before determining materials plasticity such as coal gangue and shale, the particles content less than 0.053 mm should be measured after the raw materials are crushed, and the content of this component should be controlled over 40%.This limit value can also be used as a basis for equipment selection during plant design and basic requirements for product quality control.In addition,this type of material relying on reducing particle size to obtain plasticity, whose particle size are falling in the processing of crushing, stirring, adding water, aging, milling, vacuuming, etc., or due to particles loosening caused by water effect.Therefore,determining this plasticity should be done at the outlet of the extruder or use other expression methods,in addition to the case where the limit after the comminution is less than 0.053 mm, the particle composition is greater than 40%.Another noteworthy situation is that when crushing hard or semi-rigid raw materials such as shale and coal gangue,the particle size distribution of the crushing material is very narrow,due to improper crushing equipment or processes.The direct results are poor strength of green body, or the difficulty in molding, or the poor frost resistance of the sintered product. Because unreasonable particle distribution will cause that the particles in the green body can’t reach the closest aggregation state.
Most of brick factory owners spent a lot of time and fianace to start their brick factories, however,not all of them get success, the reasons is that before starting clay brick factory, they did not conduct enough study and servey. To avoid investment loss for clay brick production, we have made the following summary for the common phenomenon of poor quality bricks and common mistakes the new clay brick facotry owners always make.
1, Malformed adobe, appears large cracks. In more serious cases, the whole adobe will split.
Reasons: the plasticity index of pug is too low, almost no plasticity.
Solution: to increase the plasticity index of raw materials, such as clay, coal slime or clay agent, etc.
For raw materials of low plasticity index, it can also be improved after aging, watering, stirring, rolling, extruding and other methods.
2, The body of adobe is not smooth, the obvious particles, more sand pits, and horns or flutes are missing.
Reasons: The shatter of raw materials does not meet the requirements of making bricks because there is much large particles.
Solutions: Install fine grinding equipment, as required for crushing the raw materials to make particles 3 mm or less.
Some kiln owners are not willing to spend money in equipping the machinery of raw material pre-treatment, such as roller crusher,double shaftmixers. Some kilns are only equipped with a pair of rollers, some only with mixers, some even neither of them. How can we get good bricks if there are bricks, tile, stone and other debris in the mud raw materials? Even if it is hard to send someone to pick them out clean. The fundamental way to solve the problem is equipped with auxiliary equipment.
3, The quality of adobe is unstable, sometimes good and sometimes poor.
Reasons: uneven mixing of raw materials
Solutions: Increase the mixer and feeder
Some brick factories are not equipped with rollers and mixers, even without the feeders, all by artificially feeding into the brick machine with shovel, which inevitably occurs two major drawbacks.①, raw material soil cannot be stirred and mixed well. The plasticity of raw soil is not exactly the same, and sometimes the disparity is very great, the Yellow River sludge is like that.②, the inside fuels such as coal, coal gangue, slime and others cannot be stirred evenly. The two heterogeneous, will inevitably lead to the instability of adobes’ quality.
4, malformed adobe and mud column, will spread immediately after cutting.
Reasons: Failure of the vacuum chamber
Solutions: a, improve the maintenance, service, repair technology of brick machine to ensure the normal function of brick machines’ properties. b, make the necessary technical transformation
b, Another reason for resulting in failure of the vacuum chamber, is the sand-based raw material, so the closed mud layer of the upper auger is too thin, easy to be drawn through, causing the vacuum failure, so the adobe could not be molded. The best way to solve this problem is to change the ratio of raw materials, to increase the plasticity index of raw materials. The other way is to cut the front end of the superiors auger to 2-10 centimeters according to the material properties of soil (must be conducted under the guidance of skilled technical personnel, don’t do it by yourself).
5, Many brick cracks on adobes or broke into two sections, more wastes after sintering.
Reasons: There are too many viscous ingredients in raw materials, so the plasticity index is too high.
Solutions: change the ratio of raw materials, reduce the plasticity index. The plasticity index of clay can be up to 25, can be properly incorporated into the coal ash, slag, fly ash or waste of brick powder to make it thin.
6, Soft adobe, easy to form, or crack after cutting.
Reason: the improper control of moisture in the mud.
Solution: soft adobe, easy to be deformed, showing that the water of sludge is too much, should reduce water. If the mud column quickly occurs crack or split of mud column after molding, which is caused by too little water in mud, it can be solved by increasing appropriate water.
7. Brick production capacity not stable
Reason: Not equip with box feeder
Solution : Some brick factory owners in order to save money, they refuse to use box feeder but some labors to feed soil manually .Therefore, soil feeding amount is not stable,sometimes more than what the extruder need, some times, less what extruder need, thus greatly influencing production capacity.
All in all, there are all kinds of raw materials to make bricks, in addition to the different climate, some abnormal situations inevitably occur in the production and it is really hard to avoid. If there are problems, knowing the following two points will be easy. One isto havea team with a strong sense of responsibility and a technical team ofprofessional mechanics. Two is to timely communicate high and difficult technical problems with industry colleagues.
●This equipment is for vacuum extruding and molding the products of fired common brick, fired perforated brick, fired hollow brick, hollow block and etc.
●Our extruder has three forms: soft plastic vacuum extruder, semi hard vacuum extruder and hard plastic vacuum extruder.
●Soft plastic vacuum extruder is suitable for the raw materials with moisture content higher than 19%;the allowed extrusion pressure is 0.4~1.8 MPa.
●Semi hard vacuum extruder is suitable for the raw materials with moisture content between 16%~19%;the allowed extrusion pressure is 1.8~2.5 MPa.
●Hard plastic vacuum extruder is suitable for the raw materials with moisture content lower than 16%;the allowed extrusion pressure is 2.5~4.5 MPa.
DZK series clay brick making machine is divided into Double stage vacuum extruder and single stage vacuum extruder:
1) Double stage Vacuum brick extruder can make three kinds of brick, solid brick, porous brick and hollow bricks. To produce different kinds of bricks, usually, only need to fix different brick die. It is composed of upper stage mixing parts and lower stage extruding parts;
2) Single stage vacuum extruder usually can produce solid bricks. It has only lower stage extruding parts;
You can get hollow bricks too if your soil quality is very high.
3) Double stage vacuum extruder has higher capaicty ,higher vacuum pressure than single stage vacuum extruder . Also double stage extruder green bricks contains less moisture