MANUFACTURE OF FABRICATED METAL PRODUCTS # 19

Background:

PT. Dharma Polimetal, established in 1989, consists of four divisions, with 199 employees, producing several products including:

The company participated in Cleaner Production Program initiated by Environmental Impact Management Agency BAPEDAL.   At the end of 1994, PT. Dharma Polimetal obtained the ISO 9002 certification from Q.A.S. Australia.

Cleaner Production Principle:

Housekeeping; Process modification

Cleaner Production Application:

The cleaner production program at PT. Dharma Polimetal is focused on the electroplating plant. Nickel chrome plating and zinc plating are used to protect metal from corrosion. Process flow diagrams for each process are shown below:

Nickel Chrome Plating Process

Soak Clean --> Rinse--> Acid Pickling--> Rinse -->Permanganate--> Rinse--> Rust Inhibitor-->

Soak Clean-->Rinse-->Anodic Clean 1-->Rinse-->Chatodic Clean--> Rinse-->Anodic Clean 2-->

Rinse-->Acid Dipping-->Rinse-->Semi Bright Nickle-->Bright Nickle-->Drag Out-->Rinse-->

Chrome Plating-->Drag Out-->Rinse-->Hot Rinse-->Drying Oven

Acid Zinc Plating

Soak Clean-->Rinse-->Electroclean 1-->Rinse-->Acid Pickling-->Rinse-->Electroclean 2-->

Rinse-->Acid Dipping-->Rinse-->Acid Zinc Pit-->Drag Out-->Rinse-->Nitric Acid-->

Rinse-->Chromating-->Rinse-->Hot Rinse-->Drying Oven

The cleaner production program at PT. Dharma Polimetal is focused on the electroplating plant. The aim of the cleaner production program was to:

Following cleaner production measures were initiated:

1. Reducing the Drag Out Volume

Dragout refers to transfer of the product from one chemical bath to another. During this process residual chemicals on the product drip are carried over into the next bath creating contamination problems and reducing the amount of available solution. Slowing the drag out, therefore, reduces the amount carried over into the next bath and results in savings of chemicals and reduction of contamination. These procedures have been implemented.

2. Reducing Rinse Water Velocity

Through setting valves to specific levels and controlling the flow rate of rinse water consumption has been reduced from 6 L/min to 4 L/min.

3. Improvement of the Cascade Rinsing System

After the chemical bath, there is a need for several rinses with fresh water or through a reverse osmosis water system. Using a counter current flow system in the cascade rinsing system allows for reductions in water consumption.

4. Reduce Chlorine Drag-In to the Chrome Bath

A high chlorine concentration in the chrome bath could cause rejection of plated parts (yellow chrome). The high chlorine concentration can be reduced by heating the chrome bath overnight at 80^oC, instead of using Erg CO3. This process also reduces the sludge in the chrome bath and extends the lifetime of the solutions.

5. Hot Water Spray Rinse after the Soak Cleaning Process

The product quality is improved by using a hot water spray rinse after the soak cleaning process.

6. Installing Additional Anodes in the Chrome Bath

Production rejects in the form of partial plating of the difficult areas such as T-joints, knees and elbows (low current area) are caused by differences in current distribution throughout the rack. By installing additional anodes such problems can be minimized.

Environmental and Financial Benefits:

1. Reducing the drag-out volume resulted in the annual hazardous waste disposal; nickel sulfate, nickel chloride, chromic acid, boric acid, sulfuric acid at no cost and a first year financial benefit of 52,500,000 Rp.
2. Reducing rinse water consumption resulting in a first year financial benefit of 15,897,000 with no cost of implementation.
3. Improvement of the cascade rinsing system, which resulted in a decrease of water consumption, costs 850,000 Rp, with a first year financial benefit of 691,000 resulting in a payback period of 15 months.
4. Reducing chlorine drag-in to the chrome bath which reduced silver carbonate and sludge at a cost of 7,600,000, resulted in a first year financial benefit of 78,414,000, with a payback period of one month.
5. Installing additional anodes in the chrome bath for a reduction of waste disposal due to lower rejects and minimized problems, cost 3,000,000. The financial benefits are included in the activities mentioned above in items 1 - 4.
6. Insulating heated process bath at zinc plating line, reduced energy losses. This process cost 1,187,000. The financial benefits ware expected by the company due to increased production capacity.

Constraints:

None mentioned.

Contacts:

Mr. Subagjo or Mr. Eko Maryanto

PT. Dharma Polimetal

Jl. Raya Serang km 24

Balaraja, Tangerang

Indonesia

Tel: +62 21 595 1629; Fax: +62 21 595 1628

 

Environmental Impact Management Agency (BEPADAL)

Directorate for Technical Development

Cleaner Production Coordinator

Arthaloka Building, 6^th Floor

Jl. Jendral Sudiman N^o2

Jakarta 10220

Indonesia

Tel: +62 21 571 2459; Fax: +62 21 571 2459

e-mail: bangtek@bapedal.go.id

Review Status:

This case study was the result of a BEPADAL cleaner production project and was taken from BEPADAL's booklet, Cleaner Production in Indonesia (see address above). It was edited for the ICPIC diskette in November 1998. It has not undergone a formal technical review by UNEP IE.

Subsequently, in March 1999 the case study underwent a technical review by Dr. Prasad Modak, Environmental Management Centre, Mumbai, India.