What material are firebricks made of? What is the manufacturing process of firebricks?
Publish Time:
2023-07-11
What materials are firebricks made of?
What are firebricks made of? Firebricks can be broadly classified into two types of materials: natural materials and artificially synthesized materials.
1. Natural firebrick materials: quartzite, quartz, diatomaceous earth, waxstone, clay, bauxite, kyanite group mineral raw materials, magnesite, dolomite, limestone, forsterite, serpentine, talc, chlorite, zircon, baddeleyite, perlite, chromite, and natural graphite, etc. The above are natural refractory raw materials, all of which can be used as materials for firebricks. However, due to the unstable composition and large performance fluctuations of natural materials, only a few raw materials can be used directly; most need to be purified, graded, and even calcined before use.
2. Artificially synthesized firebrick materials: magnesium aluminum spinel, zircon mullite, mullite, cordierite, silicon carbide, aluminum titanate, etc. These synthesized refractory raw materials can fully achieve the chemical mineral composition and microstructure designed in advance, with stable quality. The main methods for synthesizing refractory raw materials are sintering and electric melting, which are the main raw materials for modern high-performance and high-tech firebricks.
II. Firebrick Manufacturing Process
Firebrick production process: raw material selection - powder preparation (crushing, pulverizing, screening) - proportional mixing - mixing - forming - drying - sintering - inspection - packaging.
1. Raw Materials
Each batch of raw materials entering the factory must be accompanied by a product quality assurance certificate. Three sampling tests are conducted according to the indicators on the quality assurance certificate: index testing, physicochemical property testing, and repeated firing test. Only after passing these tests can the materials be put into production. Before production, acid washing and magnetic separation secondary processing must be carried out to ensure the raw materials reach the optimal state for product manufacturing.
2. Mixing
Raw material preparation personnel should strictly follow the process ratio requirements formulated by the technical department. During the preparation process, accurate weighing and timely mixing must be ensured. The specific operation is as follows: fine powder less than 100 mesh should be pre-mixed and screened through a 24-mesh sieve twice. After the binder is prepared, it should be allowed to stand for more than 24 hours. The cumulative mixing time should not be less than 20 minutes. Materials should be used on the day they are received to avoid leftover materials being mixed in. The site should be kept clean to ensure the purity of the raw materials.
3. Forming and Inspection
The forming method used in the forming process should be determined according to the product structure. However, regardless of the forming method used, the product structure should be paid special attention to during the mold installation process. The first formed semi-finished products must pass inspection before continuing production. The product model, net weight, and production date should be marked on all semi-finished products. The markings must be clear for quality tracking. Operators must conduct self-inspection and self-removal, proactively removing defective products, and not substituting inferior products for superior ones. Inspectors should check the dimensions against the drawings one by one to ensure accuracy. They should also check the semi-finished products for cracks, looseness, segregation, cavities, incomplete edges and corners, etc. Problems should be addressed promptly to ensure the yield of semi-finished products. After passing inspection, the production technology department will use a high-temperature furnace to test fire the refractory sample bricks. Only after passing the test can the drying process begin. While ensuring quality, production progress must also be guaranteed to ensure timely delivery.
4. Drying
After passing inspection, the semi-finished products should be air-dried in a cool place for 2-3 days before entering the drying kiln. In the drying kiln, they are first placed in a low-temperature area of approximately 25-30℃ for 3-5 days, then moved to a high-temperature area of 50-65℃ for forced drying for 7-15 days. During the entire drying process, operators should be careful to prevent the semi-finished products from chipping. Operators should also fill out drying records, indicating the production date, to ensure smooth firing.
5. Firing
During the firing process, kiln operators must strictly follow the firing curve formulated by the technical department. Because the firing temperature range of the bricks is narrow, the temperature control should be adjusted according to the data from the automatic testing instrument. During the firing process, operators should fill out accurate temperature rise records. During the unloading process, care should be taken to reduce man-made damage. They should also assist relevant personnel in filling out clear kiln entry and exit forms to ensure that the firing task of ceramic burners is completed on time and with guaranteed quality.
6. Finished Product Inspection
After each kiln of products is fired, the finished product inspectors must conduct timely inspections. The inspection method uses a full inspection system, including the detection of appearance dimensions, physicochemical indicators, cavities, cracks, etc. The tolerance of assembled refractory materials should be controlled within 0-0.5 for easy assembly. The inspection standards refer to the inspection standards and the user's contract requirements. Finished products that pass inspection should be neatly stacked in a cool place and covered with a film. A finished product form for each kiln should be completed and promptly reported to the production department.
7. Packaging and Shipping
After all inspections are passed and the quantity meets the contract requirements, the finished products should be packaged promptly. The supply department should provide the corresponding packaging boxes and fillers according to the user's requirements in advance and ship them according to the contract delivery deadline. During shipping, the shipping procedures should be strictly followed, and the corresponding procedures, physicochemical indicator test reports, and product qualification certificates should be provided.
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