Code No: TMS112 Price: Rs1650/- Category: Environment: Recovery

Introduction

Electroplating industry is India is spread throughout the country. They are mainly in small scale sectors with over 3,00,000 small scale units.

Metals used for plating are costly metals having superior qualities like nickel, cadmium, platinum, gold, silver, chromium etc. it has been noted that out of the total amount of these metals used in electroplating, 4% goes as waste in sludge spent wash, electroplating solutions etc. it is a necessity that these costly metals be recovered and recycled as most of them are imported to meet the existing demand.

The pollutants from the electroplating industries are invariably hazardous, as the effluents contaminate air, water and soil. Some of the polluting agents have deleterious effect on human health, examples being cadmium, lead, nickel etc. The environmental load in electroplating industry mainly consists of process waste water, hydroxide sludge and sulphuric acid. The untreated rinsing water has a lot of waste.

Iron - 150 Mg/lt
Chrome - 4.4 Mg/lt
Cr+6 - 2 Mg/lt
Zinc - 240 Mg/lt
Suspended Material - 620 Mg/lt

With the growth of industry, environmental pollution is rapidly increasing in our country. The awareness of environmental pollution control has come much later than the development of chemical industry in India. The legislation has also come much later than the industrial growth. The pollution control and abatement is therefore going to take time.

There is no doubt that pollution control measures will lead to long term gains, employment increase, increase in productivity, social justice and cleaner environment. It is necessary that the government should give more attractive incentives to encourage industry to adopt pollution control measures. These measures add to the cost of the product which ultimately goes as an additional burden to the customer. Government has to play vital role in controlling the pollution at the licensing stage itself. No license should be issue until the project is found to be environmentally safe. At the present pace of industrial development, it is important that the environment control technologies should be given the highest priority, before the situation worsen and becomes difficult to tackle technically and financially.

Need for Recycling

Adoption of proper handling and recycling methods will help in the optimization of the use of various raw materials. The recovered materials can be used again, thus reducing their consumption in these industries. The recovered materials can also be used by other industries for their raw materials.

The precious materials, of which most of the requirements are met through imports, after recovery lead to reduced exploitation of these materials and also reduces the burden on imports. The cost benefits due to implementation of pollution control measures may be long term but they yield better productivity.

Cost Benefits

1. Cost reduction through improved material and energy efficiency.
2. Marketing and sale of by products and wastes.
3. Sale of acquired technologies to others.

Role of Technology

1. Minimize consumption of raw materials, water and energy.
2. Reduction in generation of wastes.
3. Development of appropriate process technology.
4. Adoption of existing suitable control technologies to meet the regulatory standards.
5. Training of staff in pollution prevention and control and health hazards.
6. Establishing procedures for good house keeping and maintenance.

Present Status of Technology

The high waste content has been successfully recovered with development of cleaner production processes. This has resulted in huge savings in water, chemicals, degreasing substances etc. Thus recycling can help in recovery as well as providing a better surroundings. Apart from the above mentioned advantages, some others are:-

- Recycling of rinse water and effluent helps in reducing the consumption of costly bath solution thus reducing the cost of operation.

- Reduction in the problems and costs associated with the treatment and disposal of waste.

- To provide least amount of contaminants and toxic materials so as not to pollute the environment for a better surrounding.

In India though due to lack of awareness and due to economic reasons these recovery processes have not been resorted to mainly by the industries in the small scale sector.

Studies are currently in progress to properly define the plating waste market character, pin point potential clients, and obtain more detailed data on waste volumes, composition and variability. This is needed to:-

- Estimate recoverable metal yields and values, and establish design criteria for waste blending operations that would insure consistent alloy product quality.

- Identify potential impurities which may contaminate and devalue metal alloy products or create a need for an additional alloy refining step.

- Quantify volatile metal concentrations (CZO or like products) and, finally,

- Estimate and assess process operating and capital costs.

Scope and Coverage

i) Relationship and the importance of the specific topic to the broad area to which it belongs.
ii) The current status of the plating waste recycling and recovery technology in the world and in the country. Market (domestic and export) sizes and their potentials.

iii) Assessment of the technology, resource parameters such as energy, raw material, infrastructure and manpower etc. to arrive at preferred technology options available to the country.

iv) Short term and long term economic aspects preferred options along with their feasibilities.

v) Impact of the preferred options by itself and its spin offs.

vi) Recommendations:

For implementations of preferred technology option(s) indicating critical inputs such as raw material, capital goods and human resources required and their availability, investments required to commercialize, and benefits/returns expected. Maximum possible quantification is required.

For R&D / Technology development indicating the requirement of inputs and expected benefits.

vii) Action Plan for implementation of recommendations alongwith identification of:

- List of available technologies for Indian industry and

- The agencies/groups/individuals for implementation.

viii) Expected impact of recommendations, if implemented.

Methodology

This study was carried out to assess the status of electroplating wastes recycling and recovery in India and abroad. This study group was divided into two, one for the field study and other for desk study.

The field study consisted for visiting user industries, research institutions etc. agencies contacted for technology have been given in Annexure-II and Annexure-III. Agencies contacted for market survey have been given in Annexure ¡V IV. Primary information was collected through group discussions and interviews with technologists, product manufacturers, scrap dealers etc. The primary survey analysis is given in Annexure-VII.

List of manufacturers to whom questionnaires have been in Annexure-IV. Desk study helped in collecting secondary information. This was done through visits to libraries and through study of journals, books and papers recently published. The references are given in Annexure-I. Questionnaires were sent to dealers, electroplating firs and agencies. These are given in Annexure-V and Annexure-VI. Annexure- VIII gives the bibliography.

Limitations

There was lack of cooperation from the industries and power response to the questionnaires sent. The Indian Industry ad research institution have not done much in the direction of recovery and so all the technologies collected were foreign and so some of the cost data couldn¡¦t be collected.

Major Findings

Electroplating wastes cause major health hazards therefore legal measures were taken by the Indian Central Pollution Control Board.

Rules and regulations were set which broadly cover screening, testing, classification, standardizations, powers of entry, inspection, examination, closure or protection. Punishment provided under this act:

i) Imprisonment upto 5 years or a fine of one lakh rupees or both.

ii) In case of continued pollution the quantum of time and imprisonment would be further increased.

The technologies identified for recycling have been discussed in Chapter-VI in brief and recovery and recycling processes have been discussed in Chapter ¡VVIII. The major recycling processes being:-

i) Evaporative recovery: it is one of the most widely used and a reliable technique for solution concentration.
ii) Reverse Osmosis: it uses less energy than the evaporative recovery process. Though pressure required is high upto 50 atm.
iii) Ultra filtration: It requires only 1 to 2 atmosphere pressure and is used to recover water based solutions
- Low energy consumption.
- Ability to produce highly concentrated solutions for recovery.
- Only ionic materials are recovered.
- Undesirable impurities are rejected.

It¡¦s main attraction is recycling of bright nickel electroplating bath solutions.

The technology options for recovery which is one of main objectives are given in brief below:

i) Electro chemical treatment process- This process has been developed to recover metal from dilute electroplating and rinse water solution. Some of the advantages are

- Low operating costs
- It can be applied to all platable materials.

ii) Complete details are not available so the process has not been recommended.

iii) Micro filtration ¡V Heavy metals like nickel, chromium, gold, silver and copper are recovered. The disadvantage of this process is the filter cake produced which is a hazardous waste and thus it is not recommended.

iv) GM-IX process ¡V it is novel metal cyanide treatment and recovery technique. It is one of the most modern techniques and is recommended. It¡¦s pay back time is just 4 years. It¡¦s operational and installation costs have been discussed in Chapter-IX and found to be lower than the cost of loss incurred by using conventional methods.

v) Chemelec Cell ¡V This is one of recommended technologies and has been installed in many industries abroad giving profitable results. It is an electrolytic recovery process and is used to recover different precious metals like nickel, cadmium, zinc etc. Chromium is a metal which cannot be recovered by this process.

vi) Plasma arc technology ¡V This is in pilot plant stage and hence it has not been recommended. This process falls into two categories.

Plasmox ¡V Which treats waste after they have been produced.
Plascon ¡V This process treats materials as it is produced.

vii) Technology for regeneration of hydrochloric acid and metal oxides from pickle solution ¡V This process uses high temperatures of 700„aC and the process has not been recommended.

viii) Diaphragm Electrolysis ¡V it is in prototype stage and involves low cost, so it has been recommended. The process is highly flexible and can be used to recover metals like nickel, zinc, copper, cadmium, chromium etc. it has the following advantages:

- It is simple.

- Eliminates large sludge quantity resulting in saving in sludge disposal and fixation costs.

ix) Electrolytic chromate removal process.

- The advantages of the process re

a. Any hexavalent chromium bearing solution can be treated by this process.

b. No pH adjustment is required.

c. It is immune to fast changing load conditions.

d. The cell design enables to minimize the problem of passivation.

e. It is versatile.

Since details are not available so the process has not been recommended.

x) Gas fired flash smelting for metal recovery ¡V The main attraction of the process is treatment of appreciable quantities of copper and nickel in the form of complex oxides and hydroxides. Pilot plant tests have been completed. The first commercial facilities has been started recently in Beaumont, Texas, USA.

xi) Ion Exchange Method ¡V The process is mainly used for recovery of spent chromic acid.

xii) Recovery from electroplating wastes through membrane process- It is a combination of separation processes starting from filtration and ultra filtration to reverse osmosis. Since cost details are not available the process has not been recommended.

Recommendations

Keeping in mind the environmental, productivity and cost factors the following 3 processes have been recommended.

i) GM-IX process.
ii) Chemelec cell process.
iii) Diaphragm electrolysis.

Case studies have been done for the Chemelec cell process and they have shown that the process is economically viable.

Conclusions

This survey has taken into account the present technological status of recovery of electroplating wastes in our country. We have studied the technologies used world wide and those viable to our geographical and economic conditions. Recovery and recycling from electroplating wastes serves two main purposes.

i) It is economical
ii) The technologies which have been suggested are environment friendly.

Financial implication of implementing the technological options has been highlighted in this study. Valuable metals which would otherwise be lost for ever can be recovered and refused. These metals like Ni, Platinum, gold, silver etc. are very important to be recycled as we don¡¦t have any indigenous deposits for some of these or for the rest we have very limited deposits.

Action Plan

The action plan takes into consideration the following criteria.

i) Selective import of technology for recovery from spent wash.

The government should encourage foreign investment to bring into the country new technologies for high performance in the recycling and recovery field.

ii) Process development of established technology

The expertise in this field should be utilized for the further development of processes already well established, improve upon their efficiency and cost effectiveness for further research.

iii) Restructuring of supporting infrastructure.

The supporting infrastructure for carrying out studies and tests for different technologies and environmental impact should be further strengthened, and also restructured.

iv) Development of new technologies.

There should be facilities for pilot plants and more money should be invested in research and development.

v) Promotion programmes

There should be proper orientation programmes for training the technologists to handle the new technologies which are being imported.

vi) Financial aid.

The facilities provided by World Bank, IDBI, Asian Development Bank etc. should be utilized for the recovery and recycling processes to yield profits, pay back periods are also not very high.

Action plan for cleaner technologies

The cost of waste recovery/recycling is very important. The industries must formulate and adopt the techno-economically viable pollution prevention programme. The programme should be based on the facts tat technological innovation is require to reduce waste and prevent pollution.

It requires suitable planning for redesigning or modification to ensure recovery and recycling of waste.

This requires efficient implementation to conserve and maintain water material and energy balance. It also has to ensure that suitable steps are taken to reduce the recycling costs.

The energy conservation methods are equally important like:

- Combine endothermic and exothermic processes
- Integrated heat and power generation.
- Reduce temperature losses and heat, etc.
- Reduce load on rotating equipments such as pumps etc.

We have also recommended suitable investment parameters so that primary, secondary and spin offs benefits are there. The benefits of recovery of waste in electroplating industry would help generate fresh revenues, increase profitability, augment employment, and reduce pollution, thereby creating a healthier and better life.