Kaolin, especially ultrafine calcined kaolin, as a very important inorganic non-metallic material, has always occupied a very important position in the paper industry due to its excellent physical properties. The calcined kaolin production method mainly includes two parts: the ultrafine crushing process and the calcining and whitening process.
1. The ultrafine crushing process of calcined kaolin production method: The ultrafine crushing process is an important link in determining the quality of kaolin. The ultra-fine crushing of coal-based kaolin belongs to the ultra-fine crushing of hard kaolin (from 5 to 20 mm to 40 to 80 μm) (from 40 to 80 μm to -10 μm or -2 μm). The Raymond mill and vertical mill produced by Guilin Hongcheng are coarse crushing equipment, which can be used in the preliminary coarse crushing process of the calcined kaolin production method and can process 80-600 mesh coal-based kaolin; HLMX series ultra-fine vertical mill Ultrafine grinding equipment such as ring roller mill is suitable for ultrafine grinding in the production method of calcined kaolin, and can process 3-45μm ultrafine kaolin powder. It is an ideal calcined kaolin ultrafine powder mill.
2. The calcining and whitening process of the calcined kaolin production method: In view of the diagenetic characteristics of coal-based kaolin, that is, it contains some organic matter, the raw ore whiteness is only 6 to 40%, which is far from meeting the quality of coating-grade kaolin required by the papermaking industry. requirements, so the calcined decarburization and whitening process must be used. According to different requirements for kaolin quality, it can be divided into two products: medium-temperature calcined kaolin and high-temperature calcined kaolin.
Process comparison of calcined kaolin production methods: According to whether the ultra-fine process adopts wet process or dry process and the order of ultra-fine process and calcined process, the production process can be combined into four types, namely (1) wet ultra-fine process first Post-calcination process (2) Dry ultrafine process first and then calcining process (3) Calcination first and then wet ultrafine process (4) Calcination first and then dry ultrafine process. Because people have different understandings of ultrafine materials, the process routes chosen by different companies are also different:
(1) The wet ultrafine recalcination process is relatively long, but it has strong adaptability to raw materials and the product quality can meet the needs of the paper industry;
(2) The calcined-rewet ultrafine process generally requires special drying equipment and dispersing equipment. This process has weak adaptability to raw materials, but it can produce products required by the papermaking industry;
(3) Neither the dry ultrafine and then calcining process nor the first calcining and then drying ultrafine process can produce kaolin for the papermaking industry (because of ultrafine equipment), and the quality requirements for raw materials are higher.
From a comprehensive consideration, the dry ultrafine method and then the calcination process have strong practical applicability. The process flow diagram is: raw ore → crushing → pulverization → dry ultrafine → calcining → products. The advantages of this process are (1) The process is short and only three to four main equipment are required for the entire process. If Hongcheng HLMX calcined kaolin ultrafine grinder is selected, only three pieces of equipment are needed, namely: crusher, calciner Kaolin ultrafine grinding mill and calcining furnace are convenient for overall management and reasonable scheduling; (2) Reasonable energy utilization. This process places the ultrafine material process before the calcining process to avoid consuming more energy due to crushing of burned materials. If the powder calcination process is adopted, it can be regarded as a fully dry production process. In terms of process alone, energy utilization is more reasonable.
Utilizing coal-based kaolinite to produce coating-grade calcined kaolin for the papermaking industry is undoubtedly an effective way to rationally utilize coal gangue. It should be noted that the appropriate process route should be selected based on local resources and financial conditions. If you want to know more about calcined kaolin production methods and equipment selection, please leave us a message for details.