FRANKLINVILLE NEW JERSEY

Transcription

1 ABSTRACT CYANIDE DESTRUCTION AND WASTE REDUCTION IN THE ELECTROPLATING INDUSTF,Y I Cyanide destruction MR. HARRY J. DESOI, PIONEER MATEL FINISHING INC. FRANKLINVILLE NEW JERSEY A. Continuous treatment vs. batch treatment B. Chlorine vs. peroxide 1. C1. - sodium hypochlorite C. Perfered way is to put it back into the tank 1. Remove carbonates and other contaminants I1 Waste Reduction A. B. C. D. E. F. G. H. I. J. K. Educating mployees 1. This must be first step Plating rack design 1. Horizontal bars-narrow edges up 2. Eliminate all cup conditions Drain holes in parts being plated Rack parts to cause least amount of drag out. Counterf low rinsing Double use rinsing Spray rinsing into counterflow rinse tanks Air blow filters before changing 1. one gal. of concentrated bath in a filter is equal to 350 gal. of rinse water. One gal. of 50 oz./gal. total solids is 350,000 ppn. Trivalent Chrome in place of Hex Chrome 1. Hex Chrome per gal. 2. Tri C h e - as low as 0.8 oz per gal. Batch close loop treatment system vs. continuous feed treatment system. Reclaim rinse waters wherever possible and put them back into the plating solution. 1. Tripple counterflow rinse 2. Reclaim and double reclaim tanks 3. Pulsespraying, Cone spraying, mist spraying, Counterflow spraying 4. Amspheric evaporators to reduce rinse water volume or to create additional head room in plating bath 90

2 CYANIDE DESTRUCTION AND WASTE REDUCTION IN THE ELECTROPWING INDUSTRY HARRY J. DESOI, PIONEER MET& FINISHING INC. Franklinville, N.J. When developing a plan to implement waste treatment a company must be motivated in a positive way. If waste treatment is looked upon as a necessary evil and all of the conversation in the plant is of a negative nature then the endeavor is destined to failure. Motiviation can come f m several areas. You might want to leave a decent earth for your children and grandchildren. You might realize that the companies that learn to handle pollution problems will prosper. By implementing many conservation techniques your company wi 11 operate more efficiently and effectively causing the cost of treating waste to be minml. My motivation is Jesus Christ, you must find your motivation so that you will want a treatment system to work to meet and surpass all EPA and DEP regulations. In the future most major corporations will not give their work to plating companies who do not meet all DEP requirements. IBM has already told us that in the near future they will not use any plater who does not meet all EPA regulations. They will want copies of all permits, letters of approval and all manifests on sludge removal. Waste treahent must be looked upon as an asset to a company,not a liability. Let me describe quickly our plant so you have an understanding of our trealment challenges. We have a flight bar machine with three cranes. Our tanks are 10' long and 60" deep. We have 6500 gal. of nickel, 4000 gal. of cyanide copper and 2000 gal. of trivalent chrome. We plate on top of brass, steel and zinc-diecast. We process in excess of 2,200,000 sq. ft. of work per year on two shifts. Many large shelf areas and furniture frames causing excess dragout are processed. We installed the first treatment system in It included segregation, ph adjustments, treatment, ph adjustment, settle, final ph adjustment and dewatering of sludge. It was a ccmbination of continuous glow and batch treatment with a clarifier. We scrapped the system, which cost about $100,000, in It failed to meet N.J.D.E.P. and E.P.A. mandates. In August, 1981 we started up a "0" discharge, closed loop system. It consists of batch treatment, sludge concentrating, desalting of water and reusing the water. All dumps go directly into the system. Cyanide destruct is a very simple process. We do not have to destroy the cyanide past the cyanate stage. When the effluent is raised to a ph of 12 the cyanide can easily be destroyed by chlorination. This is a very rapid reaction and heat is generated. Depending on what else is in the effluent a great deal of foaming can occur. Preferably the chlorine should be added in small quantities over a determined period of time according to the cyanide concentrations. The ph is then lowered to 10 and the metals will drop out giving a relatively clear salt water. If a continuous system is being used a settling aid may have to be used to settle the metals properly. 91

3 Peroxide can also be used for the cyanide destruction. We raise the ph of the combined effluent to 10 and add the determined munt of peroxide. The reaction is very slow but since we are totally closed looped,the time is unimportant. The rapid reaction occurs when our water passes through the boiler. The higher temperature causes the reaction to destroy the cyanide quickly. The objective to treatment is waste reduction. Our efforts so far have been in sludge reduction, water reduction, copper solution reclamation and the future is nickel solution reclamation. We replaced hex chrome with trivalent throne 9 years ago. The mst important thing for us to do was to educate the people, to create a positive attitude in the plant. We had to show the workers, we have 40, that waste treatment is an asset to our cmpany,not a liability. We wanted them to understand that by being D.E.P approved we were here to stay and we were going to grow. We informed them about the conversations with some of the larger companies about the fact that they would not be placing work in companies unless they were approved. We had to get them thinking about things that would reduce waste. Get them to think about dragout, rack design, drain holes, life of cleaners, life of acids, types of products, etc. Trivalent chrome is a major factor in reducing sludge and waste. If you will look at the chart provided you will see that one gal of a 32 oz./gal. of hex chrome will produce 7.1 lb. of sludge ccanpared to 1 lb. of sludge frm a typical trivalent chrame bath and only.3 lb. of sludge frm the Envirochrame bath frm England. This is 23 tines more sludge fram hex chrome. chrome rejects are also dawn by 90% thus less striping which again gives less sludge. Parts go through system only once thus reducing sludge generation. Every idea must be considered when examining your plant. We must find out why people think certain ideas will not work. You must look at double use rinse tanks, counterflow rinsing, pump counterflow rinsing, spray rinse on top of a regular rinse tank, atnospheric evaporators, etc. Do not listen to people when they simply say an idea will not work, especially when the idea is not theirs and they want you to buy something else. Make them show in great detail, technically Why it will not work. Then call your tech-service people and ask them about what the salesperson said. This is what we have done so far at Pioneer Metal Finishing. I say so far because we intend to look at every new idea, every old idea and try the ones that will fit our plant if it gives a financial return in reducing treatment costs. We have reduced water use to a level far beyond what we ever thought possible, about 15% of use of 1972, while increasing production. This was accomplished with forced counterflow rinsing with pumps, spray rinsing on top of regular rinse tanks, reclaimofall copper rinses. We have had a closed loop treatment system for over three years. Diagram enclosed. This system costs us a little over 2% of gross sales yearly while the old system cost us 7% of gross sales yearly, based on same sales base. The new system uses about 80% less chemicals, produces 75% less sludge, 90% less in labor and all but eliminates water and sewer cost. The theory and operation is simple. You capture the water in large tanks, you treat the water, settle the sludge, remove the salts and reuse the water. 92

4 WE MUST HAVE A SYSTEM THAT HANDLES OUR WRST PROBLE2'4S AND KEEPS US IN COMPLIANCE. What we must not allow is to be talked out of examining a system because a salesman or a company criticizes a system while they are trying to sell you theirs. I have heard of people criticizing my system and they have never been inside my plant. If you tell me of smething you like in your plant, I will find a salesman or plater who has criticized it. When we had the envirochrane,in lmonth a salesman called me because he was told by a campetitor's representative that we had thrown out the trichrme we had been using for 9 years. In fact, at the time we were having trouble with the envirochrm. The problem was worked out. We must not allow these unfactual statements to go on in our plants. Many men have told me of their problems with the largest, most expensive systems you can buy. I will not criticize any system. I will openly discuss any idea or theory of waste treatment and if a certain company sells that kind of system and there are problems in the design or function then that is their problem not mine. The more facts we have the better we will be able to make intelligent, effective choices. OUR EMPHASIS MUST BE COOPERATION. Make suppliers prove themselves. Make them prove their statements about other systems. Go into great depth to find out exactly why someone may be having problems with a system or part of a system. The system may be bad or the ccarrpany running it may not be doing a god job and wants someone to fault. The plating industry is notorious for throwing things out and criticizing when much of the time the plater simply was not capable of making smething that is very worth while work. 93

5 PIONE ETAL FB ISHING I Treatment System for Electroplating Waste i A 25,000 gal. TR EP T?IE?;T Oil Tank B 25,000 gal. TREATNEKT r Mixer Tank SluLge 11,000 gal. LL I HOLDING Tank I I,-) Plating line. Total Solids I? em v a 1 I 3,000 gal. Hold ing tank Plating line Salts 0-1 5,000 gal. 1. Collect rinse waters, acid dumps and cleaner dumps in tank A. Start filling tank B. A&B hold 3 days of rinse water. 2. Mix tank A and take sample. 3. Add chemicals for ph adjustment. 4. Add chemicals to treat cyanide. 5. Mix for 5, hour and allow to settle overnight. 6. Kext day, sample tank A and test. Skim oil into oil tank. 7. Pump water from tank A to 50,000 gal. holding tank. 8. Pump sludge from bottom of tank A to sludge concentrator. 9. Cse water from holding tank in rinse water tanks of water from holding tank goes through total solids removal and into 3,000 gal. storage tank. 11. Salts are removed into salt tank. 12. Water from 3,000 gal. storage tank is used in preferred rinses.

6 HEXAVALENT CHROME BATH 16 oz./gal. Cr +6 1 gal. 32 oz./gal. I-iex Chrome Lbs. 2.0 Lbs. 2.7 Lbs. Sodium bisulfite Sulfuric Acid Lime 7.1 Lbs. Sludge 4.9 Lbs. Calcium Sulfate Lbs. Cr Hydroxide TRIVALENT CHROME BATH 2.7 oz./gal. Cr Lbs. 1 Lb. Sludge Lime 0.7 Lbs. Calcium Sulfate Lbs. Cr Hydroxide 1 gal. of Cr +3 TRIVALENT (ENVIROCHROME) BATH.83 oz./gal. Cr 1 gal. of +3 Cr Lbs. 0.3 Lbs. Sludge Lime 0.2 Lbs. Calcium Sulfate Lb. Cr Hydroxide 95