Date: 11th May 2016
Title: Analysis and Sustainable Initiatives Proposals for Operations and Management of Copper Factory Industry chosen for study : Rapsri Engineering Ltd, Bangalore, India Website :www.rapsri.com
Date: 11th May 2016
CONTENTS___________________________________________ A. About RAPSRI B. Understanding the Material Copper C. Single line description of the Process Flow Diagram D. Power Consumption E. Residues and Wastage in Each Process and the Scrap Yard F. Key Observations of Issues in the Existing Process G. Response to Questions asked to client based on the Observations H. Proposal on how the industrial activity can be improved to follow a more sustainable ecological paradigm. I. Conclusion
References Appendix A: Foundry Process Flow Diagram Appendix B: Manufacturing of Copper Alloy Components Process Flow Diagram
Date: 11th May 2016
A. ABOUT RAPSRI: Rapsri is a copper and copper alloy foundry that produces machined castings of various types using a wide range of casting processes. It is about a 1 lakh sqft facility with all processes in one floor. It has an expansion plan of an additional 1 lakh sqft in the near future. There is an adjoining 4 storey office building which looks into the shop floor at every level. They work in all three shifts and are about 300 people in all. The primary materials used in manufacturing are Copper, Zinc, Brass, Silver, Graphite, Sand , Resins, Alumina. The primary gases used in the process are Nitrogen, Argon, Carbon Dioxide and Oxygen. A number of toxic chemicals such as Cyanide, Tripolyphosphate and Trichloroethylene are also used. Copper sheets are imported from the US and Europe and 40% of the finished products are again exported to USA. The average weight of copper products manufactured is around 70T per month. At Rapsri, the alloys are poured into castings such as sand, permanent MS mould and die casting. The applications of the products produced are mainly for bearings, bushings, gears and other products. All the processes except plating processes are located together. The plating process due to the use of highly toxic chemicals is separated with a masonry wall. B. UNDERSTANDING THE METAL COPPER: Copper is considered a half noble metal but with a high solubility for oxygen in the liquid state. Many of the products manufactured in the factory are for electrical applications. The elements hydrogen and oxygen are the unwanted elements that enter copper during the remelting process. By blowing air/ oxygen on the melt surface hydrogen is removed from the melt. After which the oxygen is removed from the copper by use of degassing tubes.
Date: 11th May 2016
Pure copper is difficult to cast and is prone to surface cracking, porosity problems and formation of internal cavities. The casting characteristics are controlled by adding of elements such as silicon, nickel, tin, zinc, chromium and silver depending on the product that is being casted. C. Single line description of the Process Flow: 1. Shearing of Copper Sheets and Zinc Sheets through shearing machines (Input-Copper and Zinc) (Energy Consumption- Low ) 2. Melting of Copper and Alloys based on the melt required in Induction Furnaces.(Input – Copper and alloys) (Energy Consumption – Very High) 3. After the melting, the melt is transferred manually from Induction Furnace to Holding Furnace where the melt is stored and heated to the casting temperature. (Input – Copper Melt) (Energy Consumption – None) 4. Dipping the dyes in graphite liquid mix and then Manually pouring into Dyes. (Input – MS Dyes and Graphite Liquid under constant vibration) (Energy Consumption – Low) 5. Rough Machining in Machines where each cast is fed into machine manually. (Input – Copper Bushings, Gears etc, Lubricant) (Energy Consumption – Medium) 6. Smooth Machining of Rough Machined Items again where each cast is fed in manually. (Input – Copper Bushings, Gears etc, Lubricant) (Energy Consumption – Medium) 7. Plating with Silver of certain products to significantly improve its conductivity. It is dipped in Potassium Cyanide and then dipped in Silver solution. (Input – Copper Product, Cyanide, Silver Solution) (Energy Consumption – Low)
D. Residues/ Wastage in each Process 1. Phase 1: Shearing of primary raw material which is copper sheets- No wastage of copper, as all pieces are sent to the furnace. The packaging material of all the materials is the only residue.
Date: 11th May 2016
2. Phase 2: Melting –From the induction furnace, after the melting process, impurities such as silica and oxides are removed are disposed. Filtration is not common for copper melts as the solid inclusions have a density difference and settle down and are removed. Alumina lining for the furnace is disposed off every month. 3. Phase 3: Pouring into Dyes – No wastage as the molten liquid is poured into dyes. 4. Phase 4: Cooling with graphite liquid – Graphite dust accumulated in air settles down in the whole area. The lost graphite liquid has to be replenished. 5. Phase 5: Rough Finishing – Borings are disposed. But all shavings are separated from lubricant and sent to drier and then sent to induction furnace. The lubricant once concentrated is changed to prevent accumulation of fine particles. 6. Phase 6: Smooth Finishing – Borings are disposed. Shavings are separated from lubricant and sent to drier and then sent to induction furnace. The lubricant once concentrated is changed to prevent accumulation of fine particles. 7. Phase 7: Plating: Several Toxic Chemicals are used such as Sulphur Dioxide, Nitrous Oxide, Potassium Cyanide have to be disposed off with caution. 8. Phase 8: Checking – Defective pieces are removed and materials are separated and fed back to the manufacturing process. There is a designated organised area for the Scrap Yard. The primary materials in the scrap yard were broken Sand moulds with resin coating, borings, copper shavings which are stored to be dried and then reused, degassing tubes, MS tapes, chemical barrels, metal and plastic scrap.
E. Key Observations of Issues in the Existing Process: 1. 70% of the energy consumed is by the induction furnaces and holding furnaces. Though the factory has induction furnaces which allow it have great control in the copper mix, and also a great control with the temperature, the furnaces are ten years old, and there are more
Date: 11th May 2016
energy efficient furnaces available today. They want to phase out the furnaces in the years to come. 2. The alumina based lining provided as a dry lining in the furnace provides a clean operating furnace which helps in minimum dross build up and enables in easy cleaning. However the specification they are using has to be replaced every month. 3. Silicon, Aluminum and Iron are the primary impurities in the copper melt. The impurities are disposed off currently to the landfill without any treatment. 4. Two types of dyes are used, one which is a metal dye which is both manufactured in house with steel blocks or outsourced. The other is a copper dye which is manufactured in the factory. Sand moulds are also used, into which the melted metal is poured into. In all processes the copper melt is poured manually, which increases the factor for a mishap. In addition since the machinery are not placed as per the work flow, crossing paths during transfer of material also increases work hazards. 5. Graphite is applied as a coating in the dyes before the melted metal is poured in. The graphite dust is heavy and settles down on peoples clothing, on the floor and the air in the foundry is filled with graphite powder. Graphite is used as a solid lubricant that allows for low friction between the mould and the copper melt. Graphite coating on the mould also allows for smooth extraction of the casting. 6. The shavings from the machining processes are moved to the scrap yard where they are dried using a drier run by diesel , cooled and then sent back to the foundry. 7. In terms of the gas, Nitrogen, Argon, Oxygen, Carbon Dioxide are used. Argon for spectrographic analysis, Oxygen for Welding Operation for Machines, Carbon Dioxide for strengthening the sand moulds. 8. The plating process involves highly toxic chemicals such as cyanide, sulphates etc . There are several extractors of the fumes, but the no. of air changes does not seem to be enough to have comfortable healthy working conditions.
Date: 11th May 2016
F. Response to Questions asked to client based on the observations: 1. No separate segregated area for induction furnaces. Is there a solution keeping the layout same? Induction furnaces are a part of the foundry and are located in such a way that charging and metal tapping could easily be done. These furnaces though covered by dust and fume, extraction systems are provided over each furnace so that the smoke and other fugitives could be transferred outside the building into dust collection hopper. 2. Layout is not as per process. Starting process is in the middle of the factory. Is this also very complicated to change? At present re-layout of foundry, machine shop and plating shop is very difficult due to the civil construction that would be required for the same. This would result in stoppage of production for about 6 weeks. However when asked for alternative, without changing layout, they mentioned two possible solutions which is, using a circular conveyer or shift the machine shop upstairs so that the ground floor could be used only for foundry. These they mentioned could be done only once the volume of business become nearly double. 3. No enclosed conveyors or pneumatic transfers. Can this be introduced? They mentioned this can be introduced, however due to the initial investments required they do not want to introduce this at this point of time. 4. Scrap separation is manual. Can there be better techniques to increase yield? Their response to this, was that scrap separation will always be manual since all of their alloys are non-magnetic. The only option was to plan the production in such a way that at a time only one alloy is under production. This many not be feasible at all time. This to some extent could be achieved if rearranging the machine shop layout and designating the machines based on alloys was a possibility at this point of time. 5. Can they install floor traps for collection of spillage?
Date: 11th May 2016
No floor traps have been provided. The spilled metal is collected in drums. These drums are placed in different areas of the foundry. These spillages are then reused where possible. 6. Graphite dust settles in the whole area. What are the steps to reduce graphite dust settling down? And what are the steps to reduce graphite dust development? The graphite particles fly since they are very fine. They have planned to start using imported propriety material in place of graphite. Once the trials are done they have mentioned that they will completely phase out the usage of graphite powder. They have also planned on using graphite granules in the near future, so it does not fly and settle down elsewhere, since it is heavier.
G. Power Consumption : Average power consumption in a month is 3,85,000 kwh. The furnaces (melting and heat treatment) consume 70% of the power. There are constant power cuts in the Industrial Area, forcing industrialists to heavily depend on Diesel Generators, which also contributes to the Carbon Emissions.
H. Proposal on how the industrial activity can be improved to follow a more sustainable ecological paradigm. 1.
Mechanising of the processes to prevent accidents: Mechanising transfer of copper melt
from induction furnace to holding furnace and moving the holding furnace to the required work area amidst other all other works, is not exactly a safe procedure. It is highly recommended to increase efficiency, productivity and safety this is automated with the use of conveyor belts. 2.
No. of air changes per hour: Within the shop floor, we would recommend them to install
more exhausts, as there is not enough circulation of fresh air, and this would be detrimental to the health of the factory workers. The air is concentrated with graphite dust and metal powder both of which are injurious to health. More importantly in the area designated for plating the no. of air
Date: 11th May 2016
changes has to be increased due to the use of multiple acids in the plating process. It is recommended to introduce powerful exhausts and also introduce multiple skylights with exhausts in the slab, which can serve both for daylight and also to remove out the polluted air. 3.
Waste Minimization and Waste Management: Presently all the waste is handed over to
authorised government approved vendors. However there is no understanding of how and where it is disposed. The list below is how the waste generated can be reused for different industrial processes, and what waste can be reduced by changing the material used. a. Slag : The slag from the induction furnace is an excellent material for cement production processes and also for raising land levels in low lying areas. b. Spent Sand Moulds: One of the biggest wastage in foundry is the spent sand moulds. Currently they are dumped in the scrap yard and sent to landfill. However as per my research, this can be used in manufacturing of Asphalt concrete, bricks & pavers, compost additive, concrete, flowable fill, mineral wool products and portland cement. c. Spent Solvents from Plating Process: The practice adopted by few industries is usually batch (differential) distillation. The process is to first vapourise the solvents, then a condenser to condense the vapours and lastly collecting vessels to collect the condensate and the residues. The recovered solvents should be sent to appropriate industries for reuse. d. Plating effluent and residues containing cyanides: There are non-cyanide-based alternatives for cyanide copper, zinc, and cadmium plating processes. Though these substitutes can reduce health risks to workers, decrease environmental impact, they are not as forgiving as the cyanide solution. Tighter controls and higher cleaning standards have to be maintained in the plating area. At this point though this is discussed with the company, the advantages and disadvantages of non-cyanide baths for their applications being equal, it is more beneficial to the company to continue with the use of cyanide since it is less expensive. e. Lubricant Use in Machining: Proper disposal of lubricants in the US accounts to 20% of the cost of the lubricant. There are plastic bearings that are available as alternate to metal
Date: 11th May 2016
bearings that are self lubricant and do not need lubrication. This would reduce one of the larger residues in the copper processing which is the lubricant. f.
Water consumption: They do have an STP plant. However the water is not currently being reused either for flushing purposes or for any of the processes of manufacturing. We would recommend them to add the dual pipeline for reusing treated water
4.
Day Lighting within the shop floor: There is not enough natural daylight entering the shop
floor. We have suggested introduction of solar tubes or skylights so the central part of the factory also has natural daylight. 5.
Power Consumption: The induction furnaces that are currently being used consume a lot of
power and are not as efficient as the new Induction Furnaces available in the market. They do want to phase it out over a period of time. 6.
Renewable Energy: Being an Industry highly dependent on furnaces as one of its primary
activity, the energy consumption is very high. At present in India, there are incentives for Solar Panel Installation, and atleast a percentage of the requirement can be met with Renewable Energy.
I.
Conclusion:
Rapsri is one of leading copper foundry in the country. As a way forward, it would be integral for Rapsri to bring in sustainable practices into mainstream work flow. Be it energy consumption, renewable energy, water consumption, waste treatment, it can lead by example. By incorporating better waste management and healthy working conditions, the productivity of the staff will increase and subsequently the profit for the company. By introducing more energy efficient furnaces the electricity bill will come down. By introducing re-use of treated water, the company can be prepared for the eminent water crisis we are facing. All of the above suggestions have been shared and discussed with the client. The client is keen on incorporating some of the suggestions immediately and few where higher investments are required over a period of time.
Date: 11th May 2016
References 1. ‘Safety Practices for Machining Copper Beryllium Alloys (Drilling, Boring, Milling, Turning, Tapping, Reaming, Sawing, etc.)’, SF101 - Version 2, March, 2011 Website: http://materion.com/~/media/Files/PDFs/Corporate/BeSafetyFacts/SF101SafetyPracticesforMachiningCuBe.pdf 2. ‘Copper Slag. Process Products, Patent, MSDS Application, Suppliers, Company Profiles, Reports.’ Website: http://www.primaryinfo.com/scope/copper-slag.htm 3. ‘Pollution Control and the Plating Industry’ http://www.pfonline.com/articles/pollution-control-and-the-plating-industry(2) 4. ‘Technology Brief - BENEFICIAL REUSE OF SPENT FOUNDRY SAND’ http://www.cwc.org/industry/ibp951fs.pdf 5. ‘Electroplating’, UC Davis Chemwiki http://chemwiki.ucdavis.edu/Core/Analytical_Chemistry/Electrochemistry/Electrolytic_Cells /Electroplating 6. ‘Pollution Prevention in the Plating Process’, Metal Finishing Industry http://www.istc.illinois.edu/info/library_docs/manuals/finishing/plating.htm 7. Mowry, Matt. ‘The true cost of Bearing Lubrication’, Spring 2011 Website: http://www.igus.com/_Product_Files/Download/pdf/igus_White-Paper_True-Costof-Lubrication_June2011.pdf
Date: 11th May 2016
Appendix A
Copyright : Rapsri
Date: 11th May 2016
Appendix B
Copyright : Rapsri