Padaeng Industry Public Company Limited (Padaeng) was established on April 10, 1981. Today, the company has a total registered capital of Baht 2,260 million. Padaeng is the only private company in Southeast Asia engaged in the mining and smelting of zinc. The company's core products are Special High Grade (SHG) zinc ingot and zinc alloy, which are raw materials used in a variety of industries. The company distributes the majority of its products to domestic customers. Once domestic demand is fulfilled, any remaining production will be allocated for export. In addition to the core product line, processing by-products include limestone and sulphuric acid.
Padaeng Mine : Mining of Zinc Silicate
In 1982, Padaeng Industry was granted a 25-year concession by the government to mine zinc ore on a 250-rai area at Phratad Padaeng subdistrict, Mae Sot district, Tak province. A large deposit of zinc silicate was found there. Consequently, a zinc mine called "Padaeng Mine" based on an open ladder structure was opened in 1984. Annually, Padaeng Mine produces about 200,000-300,000 metric tons of zinc silicate with an average content of 15-20% zinc from the mine.
Calcine Plant : Zinc Sulphide Concentrate
Since 1995, Padaeng Industry began importing about 150,000 metric tons per year of zinc sulphide with an average content of 51% zinc, as a feedstock for the refinery. Because of its slightly different properties,zinc sulphide must first be roasted to form the oxide "Calcine" before the zinc can be extracted.
The company has invested Bt2,800 million to convert its operations to include a facility to produce zinc oxide (calcine). This facility consists of a roaster and an additional metallurgical sulphuric acid plant, located on the grounds of the Padaeng Industry Estate at Map Ta Phut in Rayong province, which began operations in mid - 1995. Zinc sulphide is converted into calcine during the roasting process, as sulphur constituent is changed into sulphur dioxide gas. The calcine is then delivered to the zinc smelting plant in Tak province. Certain modifications to the smelting plant had also been carried out in 1995, to accommodate use of the calcine.
Padaeng Industry is actively engaged in exploration for zinc ore in the vicinity of the Padaeng Mine and in other areas of Thailand and neighbouring countries, including Laos and Myanmar.
Zinc Smelting Plant
In 1984, Padaeng Industry constructed a zinc refinery at Muang district, Tak province, 96 kilometers from the Mae Sot Mine, for the production of zinc ingots. The initial production capacity of 60,000 metric tons per year was increased to 72,000 metric tons per year in 1987. In 1988, zinc die-casting alloy No.3 was added as an additional product and in 1997, the overall production capacity reached 105,000 metric tons per year.
With the reduction of raw material resources available at Mae Sot Mine, Padaeng Industry changed its smelting process in 1995, and began incorporating calcine as a feedstock. With the new smelting process, Padaeng Industry became one of the few smelters in the world capable of using both zinc silicate and zinc sulphide in the same production process, resulting in very low production costs for the company.