ZENITH Ltd clay brick and paver plants in the UK bring together the latest production technologies and a high degree of awareness of environmental issues and all aspects of Sustainable Manufacturing and Resource Efficiency.
As a first step, the assessment of the quality of raw material is done by experienced geologists.
The excavated clay is spread by quarrying vehicles in layers in a stockpile to achieve consistency of the mix and in order to ensure that the maximum amount of extracted mineral is beneficially used in manufacture. Extraction of clay takes place in accordance with the British Ceramic Confederation Code of Practice for mineral extraction and in accordance with all prevailing planning permissions which control working hours and the potential adverse impacts of mineral extraction such as noise and dust emissions. Wherever possible the clay is transported to the production plant without use of transport on the public highway.
The great majority of clay raw materials come from ZENITH’s own source quarries with most manufacturing sites having their own dedicated quarry close to the factory. All sites operate Environmental Management Systems meeting the requirements of BS EN ISO 14001. Appropriate restoration plans are in place for all quarries and at the end of a quarry’s working life it is often developed to create natural habitats where wildlife can flourish. Some quarries are required by the planning permission to be restored by import of waste materials to achieve an appropriate landscaped solution. In this case it is normal for the landfill gas evolved to be used for the generation of green electricity.
At the start of the manufacturing process clay is collected from the stockpile by a loading shovel and loaded into feed hoppers. Water, sand and other additives are added to the clay and mixed in accordance with the recipe for a particular product type. The clay mixture is then fed into the clay preparation plant where it is ground and homogenized.
Many of our brick and paver products contain appropriate recycled materials as part of an industry initiative known as MARSS (Materials from Alternative, Recycled and Secondary Sources). The proportion of recycled raw material varies between product types and manufacturing locations due to differences in the production process and the local raw material. All raw materials where possible are recycled within the manufacturing process to minimise waste.
The larger proportion of bricks and pavers are formed by the extrusion method. During this process the prepared clay mix is extruded through a die and then automatically cut into individual bricks. This is not dissimilar to the process used in the kitchen for the production of pasta shapes! The front face of the bricks will often be textured at this stage and may be coloured by the use of various sands and liquid or powder pigments.
The balance of UK brick and paver production is formed by soft mud moulding. This is an automated version of traditional hand brick making where a much softer clay mix – higher moisture content - is pressed into a mould and then turned out on to a pallet or tray. This is similar to making a sand castle on the beach! Normally sand is used as a release agent as the brick is removed from the mould although a small amount of bricks are released from the mould without use of sand. These are termed “slop moulded” bricks and have a characteristic soft texture.
Extruded bricks or pavers may be dried on metal pallets or stacked on a kiln car for both drying and firing. Soft mud bricks will always be dried on metal pallets due to the lack of rigidity in the product immediately after forming. Depending on the drying method used this can take typically between 1 to 3 days. In the majority of cases the heat energy for drying is waste heat transferred from the firing process. After the process of drying the bricks are grouped and set on kiln cars and transferred to the tunnel kiln or loaded by fork lift truck in cases where an intermittent kiln is used.
After drying, the majority of bricks and pavers are then fired for typically 48 - 72 hours in a tunnel kiln. This is usually heated by natural gas and achieves a maximum temperature in the range 1000 to 1100°C. The temperature profile along the length of the tunnel is kept constant and the bricks travel through the various stages of heating and cooling on a kiln car which travels on rails. Some bricks are fired in smaller intermittent kilns where the firing process takes longer as the kiln needs to be heated and cooled for each firing. In this case the bricks are loaded and unloaded by fork lift trucks.
Through firing the clay achieves strength and durability by the mineralogical processes which take place forming “glass” from the clay minerals present. The nature of the firing process also gives the basic colouration to the products. Most clays give a red based brick although use of some clays such as fireclays give buff and cream bricks. In some cases the firing process uses a deficiency of oxygen to give a “reduction” process which is used for the manufacture of Staffordshire Blue bricks or London Yellow stock bricks.
After removal from the kiln the bricks and pavers are inspected for quality and then packed and made ready for despatch. The packaged products are then taken outside the plant by forklifts and placed for storage and delivery. All our products are packaged using the minimum quantity of material necessary to protect the product during storage and transportation. Wooden pallets are generally only used at specific customer request or for some higher value products. We are continually reviewing and reducing the amount of packaging materials used in conjunction with packaging waste regulations. ZENITH also operates a Transport Strategy whereby our brick delivery vehicles employ the latest technology to minimise CO2 emissions and noise pollution.
Many of our manufacturing sites use recycled water collected in adjacent quarries or harvested from rain water. Projects are in place to increase the amount of recycled water used. It is the Company goal to work towards use of 100% non mains water in the manufacturing process.
Some of our sites use green electricity generated from renewable sources such as landfill gas. It is the objective of ZENITH Ltd to achieve a situation where the Company is a net exporter of electricity to the National Grid from the variety of renewable generation facilities created on the Company’s manufacturing sites. This would mean that the quantity of electricity generated on our sites would be greater than the electricity we require in our production processes.
All our UK manufacturing sites require an Environmental Permit to operate from the relevant Local Authority under the Pollution Prevention and Control Regulations. These permits require regular monitoring and inspection to ensure that pollution is not caused by our manufacturing operations. Close links are maintained with the Local Authority Environmental Health Departments and the Environment Agency who are involved in other environmental aspects of the process such as water discharge and waste management.
All manufacturing sites work closely with the local communities within which they operate in order to ensure that environmental issues such as dust, noise and traffic issues are managed so as to cause minimum disturbance. In the event that complaints are received from neighbouring residents then these are dealt with as part of the site Environmental Management System. Many sites operate properly constituted Liaison Committees in order to maintain close communication with local residents, Parish Councils etc.
At all our manufacturing sites in the UK we work closely with the local Wildlife Trusts with respect to habitat protection and creation. At sites where protected species exist (eg badgers or Great Crested Newts) we obtain all necessary licences from Natural England to ensure habitats are preserved. A number of our sites contain areas of land which are classified as “Sites of Special Scientific Interest” or have other nature conservancy designations. In all such cases we work closely with Natural England and the Local Authority conservation officers to manage the land in an appropriate manner.
ZENITH Ltd are active members of the Brick Development Association and supply information which is published annually as part of the Key Performance Indicators in the Brick Development Association Sustainability Strategy. This includes the Environmental aspects of manufacturing activities such as water use, emissions of Carbon Dioxide and disposal of waste materials in addition to the wider Social and Economic aspects of clay brick manufacture.
The environmental impacts of the manufacture of ZENITH brick and paver products have been assessed by the Building Research Establishment (BRE) as part of a study to identify the Environmental Profiles of building products. These profiles are then used to create environmental ratings for different forms of masonry construction in the BRE Green Guide. When used with suitable partner materials and construction methods these products satisfy the A+ Rating in the BRE Green Guide.
All operating sites in the UK have an Environmental Management System independently certified to BS EN ISO 14001 by CICS Ltd. The first such certification was achieved at the Denton factory in 1996 and this has progressively been extended to cover all sites. Good environmental practice and the concept of sustainable manufacturing and resource efficiency is therefore nothing new to the ZENITH factories in the UK.
1. Service: Life time for brick machine, brick dryer&hoffman kiln \tunnel kiln.
2. Brick plant design&build, installation and operation
3. Solid brick/ Hollow block
4. Export 25 countries, fastest cooperating.
Full automatic Clay Brick Machines is uitable to produce all kinds of hollow or solid brick & block, all kind of clay, shale, coal slack, fly ash etc, many types of machine can be choosed depend on the raw material.
Brick manufacturing plant, Clay Brick production line
The brick plant including brick machine for shaping, brick dryer(small tunnel dryer) for drying and brick kiln (hoffman kiln&tunnel kiln)for firing.
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