Introduction
High-alumina plastic refractory is made from high-alumina bauxite as the main raw material, combined with suitable binders and refractory fillers. It is used for lining high-temperature kilns and equipment.
This material offers good thermal shock resistance and is easy to apply. It is suitable for various heating furnaces, soaking pits, annealing furnaces, hot blast stoves, as well as the covers of small electric arc furnaces and burners of high-temperature kilns.
feature
| Property | Description |
| High Temperature Resistance | Refractoriness can reach 1770–1830°C, making it suitable for high-temperature environments such as steelmaking furnaces, reheating furnaces, and rotary kilns. |
| Plasticity | It exhibits a mud-like consistency at room temperature and can be applied by ramming, extrusion, etc., making it adaptable to kiln linings with complex shapes. |
| Volume Stability | It has a low shrinkage rate at high temperatures, excellent thermal shock resistance, and is not prone to cracking or spalling. |
| Erosion Resistance | It has strong resistance to corrosive agents such as molten metal, slag, and gases. |
| Construction Convenience | No complex equipment is required. It can be shaped on-site for easy repair, reducing kiln maintenance time. |
Advantage
This refractory can be customized for specific operating conditions.
It supports flexible construction and is particularly suitable for lining irregular or complex structures.
Its ease of repair also helps extend the overall service life of kilns.
Zinfon Refractory Technology Co.,Ltd.
We provide one-stop services from technical consultation to design, production, and after-sales support.
Manufacturer Direct
Factory Prices
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Customization Available
The Production Process of High-Alumina Refractory Plastics
I. Raw Material Preparation
1. Main Raw Material Selection
Aggregate: High-alumina bauxite (Al₂O₃ ≥ 48%), classified into coarse particles (5–10 mm), medium particles (1–5 mm), and fine powder (≤ 0.088 mm). It must be pre-crushed and screened to ensure a suitable gradation, typically following the "close packing principle," with fine powder making up 20%–30% to fill voids.
Other Aggregates:Corundum, mullite, or recycled refractory materials can be added to enhance high-temperature resistance or reduce cost.
Binders: Phosphates (e.g., aluminum dihydrogen phosphate, sodium tripolyphosphate) should be used in concentrations of 50%–60% in water to avoid aggregate segregation due to excessive dilution.
Additives:Plasticizers (e.g., calcium lignosulfonate, dextrin) should be pre-dissolved in water and added in amounts of 0.1%–0.5%.
Antioxidants:Finely ground metal aluminum or silicon powder (≤ 0.1 mm) should be used to prevent agglomeration.
2. Raw Material Pretreatment
Dry aggregates to a moisture content below 0.5% to avoid interference with binder curing.
If using solid phosphate binders, dissolve and filter them in advance to remove impurities.
Accurately weigh and uniformly mix all additives.
II. Batching and Mixing (Core Process)
1. Batching Principles
Use a step-by-step mixing method to ensure uniformity:
Dry Mixing:
Add aggregates (coarse to fine) into a mixer and mix for 5–10 minutes to achieve even particle distribution.
Add Binders:
Gradually add the binder solution, then mix for 10–15 minutes until the aggregate surfaces are evenly coated.
Add Additives:
Add plasticizers, antioxidants, etc., and mix for 15–20 minutes until the material forms a dough-like consistency - soft to the touch and non-sticky.
2. Key Control Parameters
Binder Dosage:
5%–10% of total mass. Adjust using a plasticity test - for example, roll a sample into a 3 mm strip and bend to 30°. It passes if no cracks appear.
Mixing Temperature:
In winter, preheat the mixer to 30–40°C to avoid binder solidification. In summer, keep room temperature below 35°C to prevent premature curing.
Equipment:
Use double-shaft forced mixers with a paddle speed of 20–30 rpm for even shear force and to avoid aggregate breakage.
III. Aging and Curing
1. Purpose of Aging
Allows full reaction between binder and aggregate to form a colloidal structure, improving plasticity and workability.
Relieves internal stress from mixing to prevent cracks after molding.
2. Operation Points
Store the mixed material in a sealed container or plastic bag in a cool, dry place (15–25°C, <60% humidity).
Aging Time: 24–48 hours for phosphate binders; 12–24 hours for clay binders.
Rotate the container 1–2 times during aging for even curing.
IV. Molding and Packaging
1. Molding Methods
Manual Ramming:
Suitable for small batches or complex shapes. Requires layered ramming using a wooden or rubber mallet. Final density should be ≥ 2.3 g/cm³.
Mechanical Extrusion:
Use a screw extruder or hydraulic press to form standard shapes (e.g., rectangular blocks) with ±2 mm dimensional tolerance.
2. Packaging Requirements
Immediately wrap molded products in moisture-proof film to prevent drying or rehydration.
Use wooden boxes or woven bags labeled with product name, model, production date, shelf life (typically 6 months), and handling instructions (e.g., "keep dry," "avoid sunlight," "no heavy stacking").
V. Special Process Adjustments (by Binder Type)
1. Phosphate-Bonded
Key Point:
Control the phosphate's neutralization degree (H⁺/Al³⁺ molar ratio of 1.5–2.0). Too low causes slow hardening; too high reduces strength.
Optimization:
Add a small amount of MgO as a coagulant to speed up hardening.
Process optimization: Add a small amount of magnesium oxide (such as MgO) as a coagulant to shorten the hardening time.
2. Clay-Bonded
Key Point:
Ensure clay is thoroughly mixed to prevent agglomeration. Improve bonding by increasing fine powder content (≤0.088 mm to 30%).
Optimization:
Adjust moisture to 8%–10% by spraying water before aging to enhance plasticity.
Process optimization: Adjust the moisture content to 8%–10% by spraying water before aging to enhance plasticity.
3. Water Glass-Bonded
Key Point:
Add acidic curing agents (e.g., sodium fluosilicate) at 10%–15% of the water glass weight. Mold within 30 minutes after mixing to avoid premature hardening.
VI. Quality Inspection and Control
1. Routine Inspection Items
| Inspection Item | Inspection Method | Qualification Standard |
| Plasticity | Strip roll or consistometer | 3 mm strip bends 30° w/o cracks |
| Room-temperature compressive strength | Cured for 3 days, tested by press | ≥5MPa (phosphate-bonded) |
| Refractoriness | Pyramid refractoriness tester | ≥1770℃ |
| Bulk density | Volumetric method | ≥2.3g/cm³ |
| Linear change rate | Measured after high temperature (1400℃×3h) | Shrinkage rate ≤1.5% |
2. Process Controls
Inspect all raw materials (Al₂O₃ content, moisture, etc.) upon receipt.
During mixing, sample every 10 minutes to check color and consistency to prevent uneven distribution ("marbling").
After aging, recheck plasticity and adjust if needed.
VII. Production Equipment and Capacity
1. Main Equipment
Crushing & Screening:
Jaw crushers, cone crushers, vibrating screens.
Mixing:
Double-shaft or planetary mixers (5–20 tons/hr).
Molding:
Screw extruders or hydraulic presses with custom or standard molds.
Storage:
Sealed silos for aggregates; climate-controlled aging rooms.
2. Production Capacity
Small-Scale Line:
≤500 tons/year, suitable for custom or repair materials.
Large-Scale Line:
≥2000 tons/year with automated batching and continuous mixing systems.
VIII. Common Problems and Solutions
| Problem | Cause Analysis | Solution |
|---|---|---|
| Poor plasticity | Insufficient binder or uneven mixing | Add binders and extend mixing time |
| Excessive hardening | Too much curing agent or high temp | Reduce curing agent, lower mixing temperature |
| High-temperature cracking | Poor aggregate gradation or low antioxidants | Optimize gradation, increase fine powder |
| Poor erosion resistance |
|
Increase Al₂O₃, use phosphate binder |
Physical and Chemical Specifications
|
Item |
Specification |
|||
|
KSL60 |
KSL75 |
KSL80 |
||
|
Al2O3 % |
≥60 |
≥75 |
≥80 |
|
|
Bulk Density,g/cm3 110℃×24h |
≥2.35 |
≥2.5 |
≥2.65 |
|
|
MOR, MPa |
110℃×24h |
≥2.5 |
≥3 |
≥3 |
|
1300℃×3h |
≥3.5 |
≥4 |
≥5 |
|
|
Crushing Strength, MPa |
110℃×24h |
≥7 |
≥8 |
≥8 |
|
PLC, % |
-1.5~+0.5 1400℃×3h |
-1.0~+0.5 1500℃×3h |
||
|
Plasticity Index, % |
12~35 |
|||
Applications
By Binder Type:
Phosphate-Bonded:
High strength and thermal shock resistance; used in high-temperature areas like blast furnaces and hot blast stoves.
Clay-Bonded:
Lower cost; suitable for medium-to-low-temperature zones such as flues and chimneys.
Typical Use Cases:
Metallurgy:
Linings and repairs for converters, electric furnaces, ladles.
Building Materials:
Transition zones and burner areas in cement kilns.
Chemicals:
Linings for cracking furnaces and gasifiers.
Others:
Refractory linings for glass and ceramic kilns.
Why chooes us?
01/Delivery cycle and logistics
Sea freight, land freight. Determine the mode of transportation according to the needs
About 30 days, customized products delivery time depends on the actual situation.
02/Customized packaging
Customize your brand
Logo customization, custom fonts, taglines and messages for packaging, signage, websites or printed materials.
Take your brand to the next level, contact us today to discuss your project!
03/Purchase ZINFON Monolythic Refractory at Reasonable Prices
The price of Monolythic Refractory is a known key factor influencing customers' purchasing decisions. Therefore, we offer affordable Monolythic Refractory for sale. Here are several reasons why ZINFON provides Monolythic Refractory at competitive prices:
Factory price
By collaborating with ZINFON, we ensure that customers enjoy the ex-factory price of Monolythic Refractory, reducing costs from middlemen or distributors. This allows customers to obtain the most cost-effective pricing directly from the source.
Low raw material cost
ZINFON is surrounded by abundant mineral resources. With these high-quality materials, customers can obtain products that are both affordable and excellent in performance.
Mass production
ZINFON possesses advanced production equipment and technologies, enabling the factory to achieve economies of scale and reduce unit production costs. Meanwhile, it ensures a continuous supply of high-quality products at preferential prices.
It is worth noting that while price is an important factor, it should not be the sole determinant of your purchasing decision. When buying Monolythic Refractory from ZINFON, quality, reliability, and technical support are equally important considerations.
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Provide professional after-sales protection
Our address
Qinghua Management Dist., Dashiqiao City, Yingkou City, Liaoning, China
Phone Number
+8613700131695
+8618540210631
By choosing ZINFON as your supplier, you can access high-quality refractory bricks, a wide range of other refractory materials, and comprehensive support. Contact ZINFON Refractories immediately to discuss your specific requirements and obtain customized solutions!
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