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The first sulfuric acid plant was constructed by the DAVY company as a Lurgi Type plant in 1979, which uses the double contact process. At that time it was designed to produce 80,000 Cu-tons a year, later revamped to 140,000 Cu-tons. Additional facilities: Exhaust gas desulfurization

The second sulfuric acid plant was built according to Monsanto's double contact process, and it has its own characteristics. We maintain more than a 99.98% conversion rate through a Cs catalyst and treat a high density of SO₂(13.2%) with our compact facilities.

In our company, sulfuric acid production can be largely divided into 4 sections: Cleaning, drying, converting, and absorbing. The Sulfuric acid production process: preparing SO₂gas at the smelter then converting it into SO₃at the converter, and finally absorbing it
SO₂ + 1/2O₂ → SO₃ + 23,000 cal SO₃ + HO → HSO + 31,400 cal

	Among the gases coming from the smelter, all the ingredients except SO₂ are impurities. Accordingly, the object of the cleaning process is to get rid of the impurities completely. SO₃, Dust, F, As, Pb are the impurities, and they differ depending on the condition of the refinery. F is important in that it erodes the facilities at the downstream process and shortens their life span. Another important role of this process is to lower the gas temperature from 350℃ to 50℃.

	In this section the gas flows through the SO₂ Blower, before entering the dry section. The moisture in the gas and air from the smelter is removed at the drying tower. Managing the concentration of circulating acid in the tower is important because the moisture can cause erosion at downstream facilities.

	In this section SO₂ is converted to SO₃. An exothermic reaction produces steam. The conversion rate should be maintained at a level of 99.98%. When the rate is lower, it can be a burden to the desulfurization plant. The converter consists of four passes of catalyst with the ingredients V₂O₅ and Cs.

	* V₂O₅ : 6 ~ 8% * SiO₂ : Carrier

	Gas, which goes through the third pass of catalysts, is mostly SO₃. It is absorbed at the interpass-absorbing tower. The remainder of SO₂ gas is once again converted into SO₃ at the 4th layer of catalyst, and absorbed at the final absorption tower. That is why it is called the double contact process. The most important thing in managing the absorbing tower is the concentration and the temperature of the circulating acid.

Our company has 3 factories for desulfurization as well as a Scrubber for the precious metal plant and a dryer in the smelter. We built the first desulfurzation factory in 1988, and produced sodium sulfate with NaOH as an absorbing agent. After that, we partially remodeled the old facility and have used Mg(OH)₂ as an absorbing agent since 1996, as the price and consumption rate of NaOH had gone up.

The first and second desulfurizing processes are basically the same, although they use different absorbing agents. The processes can be classified as absorption, oxidation, and the final treatment. In the first plant, MgSO₄ slurry is sent to smelter. In Plant 2, we use CaCO₃ to produce CaSO₄2H₂O from hydrated gypsum sludge.

As a business diversification in 1989, a factory for PSA was built. New technology was introduced from Japanese companies such as Mitsubishi and IWAKI Glass, enabling us to produce sulfuric acid for semi-conductor of VLSI. At that time, our main facilities such as our vaporizer, absorbing tower, stripping tower were made of Glass. When these problems were solved, the quality was upgraded to 4Mega, 16 Mega, 64 Mega. Now, new sulfuric acid for 256 Mega is being produced

The PSA process can be largely divided into vaporization, absorption, SO₂ stripping, storage, and packaging. Except for the use of L-SO₃ as raw material gas, it is similar to an industrial sulfuric plant.

SO₃ + H₂O → H₂SO₄

At the absorbing tower, FRW is used to produce general industrial sulfuric acid. But this process, uses UPW (Ultra Pure Water: the most pure water which can be produced by the state of the art technology these days)

As part of a business diversification in 1984, a factory for L-SO₃ producing 750 tons a month and factory for L-SO₂ producing 300 tons a month were built with technology from the American company, Stauffer. As the amount of sales increased, those factories were extended in 1988 and 1989. We enlarged the factories again in 1992 and they have been maintained until today.

The current processes of L-SO₂ and L-SO₃ are operated under the authorization of the KFDA (Korea Food and Drug Administration). L-SO₂ is governed by the High Pressure Gas Act, and L-SO₃ is under the Environment Act. The process is: The converted SO₃ is absorbed by the fuming sulfuric acid. When its concentration reaches 30-35% SO₃, SO₃ is vaporized, condensed, and enters the storage tanks. It is used as a PSA material. In the L-SO₂ factory, SO₃ reacts with molten sulfur and becomes SO₂ and it is refined, compressed, condensed, kept in storage tanks and sold.

L-SO₂: 2SO₃＋ S → 3SO₂→ L-SO₂

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compressed and condensed

L-SO₃: SO₃＋ H₂SO₄→ H₂SO₄·SO₃ → SO₃→ L-SO₃

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compressed and condensed