ThaThai Co., Ltd. Received the Organization’s First CSR DIW in 2011

ThaThai to Supply Alum in the Times of Great Relieve Efforts as Demands for Fresh and Drinkable Water Rise

            Kittipat Chuitoi, the Deputy General Manager of ThaThai Co., Ltd in Samutsakorn, says the company is not effected by the flood disasters as the water has not reached, and according to the latest report from the government, will not reach the areas surrounding ThaThai Factory. Kittipat added, in the times of natural disaster, such as, floods, Thathai is bound by the responsibilities to the country and its people in producing Aluminium Sulphate, or Alum. As Alum is crucial to purify and treat water from debris and other unwanted elements. ThaTHai’s main outlet and client is the Metropolitan Water Authority (MWA,) of which is used in the process of purifying water for the public.

            Kittipat further commented that the production of ThaThai’s alum is not interrupted, mainly, because most of our suppliers and raw material resources are abroad and still in operations. Usually, ThaThai import raw materials in the amount that will be sufficient to supply Thailand for the next 6 years.

            Kittipat is very proud of the latest achievement in receiving the 2011 CSR DIW, which is awarded to companies with outstanding social responsibilities towards its employees and the society at large. This is the second year ThaThai has applied for Thailand CSR DIW, but was the first year for the company to be certified for the CSR DIW. ThaThai has also qualified for ISO 9000, ISO 14000 and  the TIS 41-2529 and 165-2542 earlier in its history.

            ThaThai was founded in 1989 under the registration capital of ฿120 million. It was constructed as a Sulphuric Acid producer. The company began its full operations in 1993, with the full capacity production of 200 tons per day. Between 2002 and present day, ThaThai expanded its operations into producing aluminum sulfate with full production capacity at 60,000 tons per year.

            Aluminium sulfate is used in water purification and as a mordant in dyeing and printing textiles. In water purification, it causes impurities to coagulate which are removed as the particulate settles to the bottom of the container or more easily filtered. This process is called coagulation or flocculation.

When dissolved in a large amount of neutral or slightly-alkaline water, aluminium sulfate produces a gelatinous precipitate of aluminium hydroxide, Al(OH)₃. In dyeing and printing cloth, the gelatinous precipitate helps the dye adhere to the clothing fibers by rendering the pigment insoluble.

            Aluminium sulfate is sometimes used to reduce the pH of garden soil, as it hydrolyzes to form the aluminium hydroxide precipitate and a dilute sulfuric acid solution. An example of what changing the pH level of soil can do to plants is visible when looking at the Hydrangea macrophylla. The gardener can add aluminium sulfate to the soil to reduce the pH level which in turn will result in the flowers of the Hydrangea turning a different color.

Raw materials and production process

            Aluminium trihydrate is purified from bauxite. Commercial bauxite (30-75% Al2O3)

deposits occur in Australia, Jamaica, France, Guyana, Guinea, the USA and Brazil. Bauxite

ore is dissolved in strong caustic soda to form sodium aluminate. The aluminium trihydrate

is then precipitated by neutralisation (usually with carbon dioxide) or by autoprecipitation

(the Bayer process).

Step 1 - Reacting the raw ingredients.

            The aluminium trihydrate is transported and stored in one tonne bags. Each bag is carried by hoist to the feed hopper, where it is opened and conveyed to the reaction tank. The reaction water, trihydrate and sulfuric acid batch is stirred for a period of time with water vapour

exiting through the stack.

Step 2 - Making the final product

            After the reaction period either liquid or solid alum is made. If liquid, the concentrated batch is run into the dilution tank filled with the dilution water where it cools over time. The liquid

alum is then filtered and pumped to storage. There are overhead load out facilities at

Morrinsville where a number of liquid chemicals are available in dispatch tanks for road

tankers. If solid is made, the concentrated alum is run into the casting pans where it sets, aided by fan cooling. The pans are forklifted to storage racks and from there they are taken to the

Crushing Plant and dropped into a hopper. The pieces are broken further by a large kibbler

followed by a small kibbler and then screened. Oversize particles go to a bagging hopper and

are sold as kibbled product. The screened alum is rotary crushed and further screened to

either return to the rotary crusher or be bagged as ground product. Dust is continually

collected through an extraction system and is sold as product. The Crushing Plant is flexible

and the ratio of kibbled to ground aluminium sulfate is variable.

ENVIRONMENTAL IMPLICATIONS

            All site effluent is managed by a Distributed Control System (DCS). Site run off and any

spills are collected in sumps. All collection sumps have level probes which, once a limit is

reached, start the sump pumps which pump the water through a common pH pot. If the pH is

outside limits then the water goes to holding tanks where it is used with reaction water. If the

pH is acceptable the water is discharged to the effluent stream. The effluent stream is pH

monitored and is analysed for suspended solids.