Powder calcination temperature in high-temperature rotary furnace

The temperature range for calcining powder in a high-temperature rotary furnace is usually between 600 ℃ and 1600 ℃, and the specific temperature needs to be determined comprehensively based on material characteristics, process requirements, and equipment performance. The following is the key analysis:

1. Typical material calcination temperature range
Metal oxides and ores
Zinc oxide (ZnO): When calcining zinc concentrate (ZnS), the temperature is usually controlled between 900 ℃ and 1100 ℃ to ensure carbonate decomposition or sulfide oxidation.
Aluminum oxide (Al ₂ O3): In the two-stage calcination process, the first stage dehydration temperature is 950 ℃, and the second stage crystal transformation temperature is 1250 ℃, resulting in a higher content of the final product (α – Al ₂ O3).
Iron ore: When reducing and calcining to produce iron powder, the temperature needs to be adjusted according to the reducing agent (such as hydrogen or carbon monoxide), usually between 800 ℃ and 1000 ℃.
Non-metallic mineral
Cement clinker: When calcining limestone (CaCO3) and clay, the temperature needs to reach 1350 ° C to 1450 ° C to generate key mineral components such as tricalcium silicate (C3S).
Limestone: When calcined separately, the temperature is controlled between 900 ℃ and 1100 ℃ to ensure the decomposition of calcium carbonate into calcium oxide (CaO) and carbon dioxide (CO ₂).
Kaolin: Dehydration and calcination temperature ranges from 600 ℃ to 900 ℃ to obtain metakaolin, which is used in fields such as ceramics and papermaking.
Chemical raw materials and new materials
Lithium battery cathode materials, such as nickel cobalt manganese oxide lithium (NCM/NCA), require precise control of calcination temperature between 700 ℃ and 900 ℃, with temperature uniformity of ± 5 ℃ to ensure higher crystal conversion rate.
High purity oxides, such as zirconia (ZrO ₂) or yttrium oxide (Y ₂ O3), can be calcined at temperatures ranging from 1500 ℃ to 1600 ℃ to meet material purity and performance requirements.

2. The core elements of temperature control
Material Characteristics
The chemical composition and physical properties (such as melting point and thermal stability) directly determine the calcination temperature. For example, limestone (CaCO3) decomposes at a lower temperature, while bauxite (Al ₂ O3) requires a higher temperature to promote solid-phase reactions.
Process requirements
Different processes have strict requirements for temperature uniformity, heating rate, and insulation time. For example, two-stage calcination of alumina requires segmented temperature control, while lithium battery materials require rapid heating to avoid grain coarsening.
Equipment performance
The insulation performance, burner efficiency, and temperature measurement technology of a rotary furnace affect the accuracy of temperature control. Modern equipment adopts PID control algorithm and infrared thermal imaging instrument, which can control temperature fluctuations within ± 5 ℃.
environmental conditions
In high-temperature environments, it is necessary to lower the calcination temperature appropriately to prevent equipment overheating, while in low-temperature environments, the temperature needs to be increased to compensate for heat loss.

3. Practical cases of temperature control
Aluminum oxide industry
Process control: Two stage calcination (950 ℃+1250 ℃) with higher content of α – Al ₂ O3.
Energy saving measures: Waste heat power generation products recover electrical energy, and oxygen enriched combustion reduces fuel consumption.
Production of lithium battery materials
Temperature uniformity: ± 35 ℃, higher crystal transformation rate.