Commonly known as china clay, kaolin is used as a functional additive for a wide variety of consumer products. The procedure of mining and processing this type of clay is carried out on the manufacturing scale. It begins with extracting the ore from small to very large open-pit mines. After that, the kaolin mining industry processed the ore through several stages, from removing its impurities to performing thermal and chemical treatment.
Every step of this procedure is performed by taking the social, economic, and environmental impacts into account. Therefore, it will enhance the benefits and eliminate serious threats caused by the mining industry. Here you can learn more about how the industry of kaolin mining works all the way to the procedure of how the kaolin is processed.
How Kaolin Mining Industry Works
Mining is defined as an activity to extract valuable mineral resources to achieve significant economic and social benefits. In the case of mining kaolin, the industry considers the kaolin life cycle to determine the next stages of the mining process, which include four main stages: Exploration, Resource Development, Mine Design and Construction, as well as Closure and Restoration.
The first, yet one of the most important steps of mining kaolin is exploration. While considering the social and environmental impacts, this step is performed by following clues and sampling the subsurface.
In the phase of following clues, the kaolin mining industry often works hand in hand with a geologist to identify promising areas around the mine and search for any sign of kaolin mineralization.
Once the clues are located, the exploration is proceeded to sampling and testing the deposit. This process also goes by the term “subsurface sampling”. In kaolin mining, the industry uses rotary core and auger drilling methods, performed by drilling a small number of test holes to confirm the discovery of the clues.
2. Resource Development
The next step after exploration is developing the resources. To estimate the mineral resources before mining the area, a close-spaced drilling process is required. Several important aspects are taken into consideration during this phase, including the drill hole estimation, the tonnage and grade, as well as the economic viability involving the thickness and quality of kaolin clay.
The process of resource development can be done using two different methods. The first one is based on conventional approaches by delivering maps, spreadsheets, and cross-sections. Meanwhile, the second method is done by utilizing 2D or 3D technologies; one of the most popular ones is using a computer-driven geostatistical modeling technique. Regardless of their different approaches, both methods have the same objection: producing valid results related to the geological quality estimation of the kaolin mining area.
3. Mine Design and Construction
The next thing that the kaolin mining industry should do is designing and planning the mine construction. This stage includes several activities such as determining the size of the mine, creating a mine layout, and deciding on the mining methods, production requirements, and equipment needed during the process. At this stage, the industry should also apply for a permit to begin the mining procedure.
When everything is ready, the extraction of kaolin can be started from the open-pit mines. It begins by considering the geotechnical aspects of the mining site. Then, the engineers will start working after designing highwall slopes to make sure the site safety. They can use wheel tractor-scraper, loaders, or excavators to remove overburden. After it is relocated, the mining of kaolin can officially begin.
4. Closure and Restoration
Another crucial step that shouldn’t be missed is the process of closure and restoration. This stage is performed after removing the mineral by grading and revegetating the mining land. Kaolin mining sites are commonly restored into a community recreation area, wildlife habitat creation, or an area for farming, hunting, and fishing.
For industrial companies, this step is as important as the mining itself. In fact, it should be carried out carefully to maintain significant resources of the mining life cycle. Because of this reason, industries usually make use of sustainable land-management practices. It is aimed to reduce the risks of long-term environmental issues that may occur after finishing the mining project.
How Kaolin is Processed
After the mining procedure is carried out, the next step to completion is processing the kaolin. Aiming to enhance and control various properties contained in the clay, the kaolin mining industry divides the process into three basic types: wet, dry, and thermal processing with chemical treatment.
1. Wet Processing
To begin the wet processing, a dispersed mineral-water suspension is prepared and passed through screens, hydro-separators, or hydro-cyclones. The main objective of this initial step is to remove grits or coarse mineral particles.
In later stages, kaolin that has been freed of grits will be classified into the fractions of specific particle size. After the fractionation is complete, the procedure will be continued to remove mineral impurities, including iron oxides and iron hydroxides.
2. Dry Processing
The process of dry processing or air flotation is considered less expensive than wet processing because it involves fewer stages. The procedure begins by milling the crude kaolin, classifying the air to remove the grits, and drying the kaolin to reduce its moisture. Compared to wet-processed kaolin, the final products of dry processing are usually less bright and have higher contents of grits. Therefore, its market price is relatively lower.
3. Thermal Processing with Chemical Treatment
Also known as the calcination procedure, thermal processing with chemical treatment involves high-temperature firing by combining wet and dry processing stages. This process is regarded as the most widely used kaolin processing because it results in better, brighter, whiter, and harder contents.
High-temperature firing in thermal processing is useful to enhance kaolin’s chemical resistance and mechanical properties. For this reason, the final products of this process generally come with a high level of rigidity, toughness, and dimensional stability.
Looking at the procedures of how kaolin is mined and processed, it’s fair to say that the kaolin industry is closely linked to complexity. However, throughout the years, the kaolin mining industry has improved its understanding of mining and processing methods. It leads to innovative approaches that can be beneficial for business by enhancing reputation and improving the efficiency of the mining operation.