Named from the hill where the mineral was first mined, kaolin or China clay is a natural soft clay containing a high amount of kaolinite mineral. Ever since its first recognition, kaolin has been mined all over the world, including Indonesia. Kaolin from Indonesia offers a wide range of quality based on the location where it was mined.
Generally, pure kaolin has a white color, but over time people have been combining kaolinite with other clay minerals based on consistency and industry needs. For example, the kaolin may have subtle pink or green hues from the addition of plant or iron dioxide.
Originally, kaolin was used only to treat stomach aches and create porcelain in China. However, the constantly growing industry demand makes kaolin needs to branch out to other types of industries. Now, kaolin is currently utilized in Indonesia in a variety of products such as porcelain, sanitaryware, toothpaste, paint, paper, cosmetics, refractory, filler, and more.
Kaolin from Indonesia is famous for its quality and abundance of quantity. Read on to learn more about this famous, ubiquitous mineral.
Where Does Kaolin Come From?
Kaolin from Indonesia has a pretty long way to go from its origin in the ground until it can be used for a variety of industrial processes. Below we’ll see a glimpse of its creation process and where it comes from.
To begin, kaolin must be mined using a water jet. Following that, the kaolinite is centrifuged with kaolin slurry, which removes the sand, and the kaolinite is ready for its triple filtering, which uses 100 to 325 mesh screens.
Kaolinite will be purified and solidified after being filtered using a high-pressure pump and filter press. At this step, a kaolin lump with a 33 to 35 percent moisture content is produced.
If you want kaolin with a lower moisture level, it must be dried naturally until the moisture level is between 12 and 14 percent. In comparison to drier kaolin, which has just 1-4 percent moisture, this kaolin is considered medium in moisture.
Kaolin from Indonesia: A Brief Overview
Indonesia is one of the countries that possess a lot of kaolin mine sites. Situated in the Ring of Fire, kaolin sedimentary will most likely be found around West Kalimantan, South Kalimantan, and Bangka and Belitung Island. On the other hand, other sources of kaolin include Sumatera, Java, and North Sulawesi Island.
However, there are more kaolinite sources aside from the major ones. Some potential sources of kaolinite are spread all across Indonesia, namely Bandar Island, Belilas, Indragiri Hulu, Pondok Kelapa, Garut, Tasikmalaya, Blitar, Trenggalek, Martapura, Polewali, and Paniai. These locations are spread from the west to the east of Indonesia, making it easier for industries and exporters alike to mine kaolin for their industrial processes as well as export business.
Kaolin Trade Activities in Indonesia
Kaolin shipments from and to Indonesia must comply with the Indonesian Minister of Trade Regulation on Export Provisions for Processed and Purified Mining Products. The export procedure may only be carried out if the exporters hold a Ministry of Trade export registration license, an export approval license, and a separate export license.
Furthermore, exports of processed and purified mining goods, such as kaolin, can be carried out once the business has followed verification or technical inquiry processes. Such processes are carried out to guarantee that the mining products that will be exported meet the minimal quality requirements set by the Indonesian government.
From here, we can see that kaolin is a great asset for many countries, including Indonesia. The abundance of kaolin mining sites in Indonesia means that the country houses a lot of high-quality sources that can be processed into multiple industries, as well as exported to other countries.
Three Types of Industry Grade Kaolin Products in Indonesia
1. Kaolin Lump
Kaolin lump is an industry-grade kaolin product with a moisture content ranging between 33% and 35%. It has gone through several steps of processing, including 325 mesh screening before moving to the pressing filter by high-pressure pumping. This China clay mineral has larger, irregular chunks as compared to other kaolin types.
2. Kaolin Noodle
In mineral processing, kaolin noodle is the next step after kaolin lump. A natural drying process transforms it into a white kaolin noodle with a moisture level of 15% – 20%. It is smaller in size and form.
3. Kaolin Powder
Once kaolin noodle goes through a natural drying process and a disc milling machine that crushes it into fine particles, the result is a kaolin powder with a moisture content of around 1% to 4%.
Some people might wonder why kaolin is divided into three products, despite having the same quality and end result. The reason is that various phases of production are required during the management of kaolin moisture since it influences the industrial process, as well as cost-effectiveness and efficiency.
The Nature of Kaolin from Indonesia
As for Indonesia, Bangka-Belitung has been the largest kaolin producer due to these abundant mineral deposits. According to Agustina A.Y. Simanjuntak and E. Kusrini (2018), kaolin from Bangka-Belitung has almost the same quality as kaolin from Ronong, Georgia, and China.
Let’s take a look at the table below to see the kaolin quality difference among the five countries.
|Loss on ignition (LOI)
Moreover, kaolin from Indonesia has several qualities like natural brightness and whiteness, low-content impurities, and good-for-firing properties. Likewise, they have been traded domestically and internationally as industrial kaolin mostly for ceramics, paint papers, and rubbers.
Bangka-Belitung has its niche market by offering the varied quality of filler-grade kaolin (low-cost kaolin with high brightness level) for the papermaking industry.
By its nature, kaolin minerals are more likely to occur and develop favorably in the humid tropics kind of climate. It makes Asian kaolin, including kaolin from Indonesia, have distinctive properties for different industrial and commercial applications to offer to the global kaolin market.