Jiangxi is one of China's resource-rich regions for kaolin. Kaolin ore in the Gannan area is characterized by relatively high aluminum content and fluctuating iron and titanium impurities, and is widely used in ceramic bodies and paper fillers. As downstream markets have raised their requirements for the whiteness and particle-size consistency of calcined kaolin year after year, a local non-metallic mineral processing company decided to build a new calcination line with a daily raw ore processing capacity of 100 tonnes, replacing its existing small-scale traditional kiln capacity. After multiple rounds of technical comparison and on-site inspections, the project owner ultimately selected Henan Hongke Heavy Machinery Co., Ltd. as the turnkey equipment supplier, responsible for the full-process engineering design and main equipment supply from raw material pretreatment to finished product cooling.
Process Scheme and Equipment Configuration
The production line adopts the mature process route of "crushing and grinding — suspension preheating — rotary kiln calcination — rapid cooling." Raw ore is coarsely crushed by a jaw crusher and then fed into a Raymond mill, ground to a fineness of 200 mesh or finer to ensure the specific surface area and heat exchange efficiency of the kiln feed. In the preheating stage, high-temperature flue gas from the kiln tail is used to perform preliminary dehydration and dehydroxylation of the powder. The flue gas temperature drops from approximately 900°C to about 300°C, and the material is preheated to 500–600°C, effectively reducing the thermal load inside the kiln.
The core calcination equipment is a Φ2.5×50 m rotary kiln with a 3.5% inclination and a variable-frequency speed range of 0.6–1.5 r/min, equipped with a multi-channel burner and a PLC temperature control system. In response to the instability of iron and titanium chromophoric elements in Jiangxi kaolin, the Hongke technical team installed multiple temperature measurement points and atmosphere adjustment interfaces inside the kiln. Operators can fine-tune the oxidation atmosphere intensity according to differences in raw ore batches, suppressing iron-phase coloration and ensuring that the whiteness of the calcined product remains stably above 88%. The clinker discharged from the kiln head at approximately 1000°C enters a vertical cooler directly and is forced-air cooled to below 100°C, which both locks in the active phase of metakaolin and facilitates subsequent grinding and packaging.
Operational Performance and Customer Feedback
Since commissioning, the line has stably processed 100–105 tonnes of raw ore per day. The whiteness (ISO) of the finished calcined kaolin is maintained in the range of 88–90%, and the 325-mesh residue is controlled below 0.5%. All indicators meet the incoming inspection standards of customers in the ceramic glaze and paper filler segments. The project manager stated that the key reason for choosing Hongke was its targeted adaptation to Jiangxi ore characteristics — under equivalent operating conditions, the utilization rate of kiln tail flue gas waste heat is noticeably improved compared with the previous scheme, and the standard coal consumption per unit product is reduced by approximately 20% compared with traditional hollow kilns.
In terms of environmental protection, the kiln tail flue gas is treated through a two-stage process of cyclone dust removal plus bag filter dust removal, and the particulate matter emission concentration is below 20 mg/m³, meeting the local environmental protection department's regulatory requirements for non-metallic mineral processing projects. The entire line has a high degree of automation; only two operators are needed in the central control room to complete linked monitoring from feeding to discharge, significantly reducing the frequency of manual intervention.
Case Summary
A kaolin rotary kiln production line with a capacity of 100 TPD represents a medium-to-upper capacity tier in Jiangxi and even in China's kaolin processing landscape. This project verifies Henan Hongke Heavy Machinery Co., Ltd.'s engineering implementation capability in the field of small and medium-sized calcination lines: with a preheating system adapted to ore characteristics and adjustable-atmosphere calcination as the core, supplemented by compact cooling and dust removal configurations, it ensures stable product quality while controlling the investment scale. For kaolin processing enterprises in Gannan and surrounding areas that face environmental rectification pressure on traditional kilns and intend to upgrade their calcination equipment, this case provides a referenceable technical path and a basis for equipment selection.