The Jewelry Manufacturing Industry Fernando Florez Supervising Haz-Mat Specialist LA Co. CUPA

Introduction Jewelry Industry Overview Jewelry Manufacturing Process Jewelry Sampling Project / Hazardous Waste Concerns

Industry Overview The LA Jewelry Mart District is the second largest manufacturing market in the U.S. There are 30 buildings currently used by approximately 400 jewelry manufacturing and repair businesses. Six buildings have been converted to full manufacturing.

Industry Overview The District is comprised of a complete jewelry network support system:  Precious stone sales.  Precious stone setters.  Jewelry sales.  Jewelry repair.  Jewelry manufacturing.  Jewelry manufacturing equipment sales. Many of the businesses in the LA Jewelry District are family owned, with less than 5 employees.

Jewelry Manufacturing Process There are 9 process steps to manufacture jewelry. Various raw materials and hazardous materials are utilized in the process. Various hazardous wastes are generated.

Jewelry Manufacturing Process Step 1 - Jeweler conceptualizes and creates a master original piece.

Jewelry Manufacturing Process Step 2 - Preparation of Rubber Mold. Original piece is placed between 6 molding rubber pieces & secured in molding frame. Mold is placed in Vulcanizer unit at 325 F for 35 min. Mold is cut opened and original piece is removed. 3- D space is cut out.

Jewelry Manufacturing Process Step 3 - Preparation of Wax Piece. Wax injected into empty mold at 180 F Wax piece is removed from rubber mold and attached to a sprue. Several wax pieces can be attached for mass production.

Jewelry Manufacturing Process Step 4 - Preparation of Investment Mold Wax Sprue is placed into a stainless steel cylinder. Investment Plaster is poured and set to dry for 10 min. Cylinder cured in Kiln 1500 F for 4 hours. Wax melts thus leaving a 3-D space inside cast.

Jewelry Manufacturing Process Step 5 - Casting by Centrifuge OR Vacuum. Cylinder is placed in Centrifuge unit. Gold pellets are melted at 1600 F in crucible with torch. Cylinder is place in Vacuum unit. Gold pellets are melted and poured cylinder.

Jewelry Manufacturing Process Step 6 - Devestment. Cast cylinder is washed to remove the jewelry sprue from the plaster. Sprue Tree is ready for individual piece removal.

Jewelry Manufacturing Process Step 7 - Jewelry Pieces are Cut From Sprue Tree and Soldered, Grind and Polished. SolderingGrindingPolishing Pieces are cut from sprue. Cyanide bombing

Jewelry Manufacturing Process Step 8 - Cleaning and Removal of Oxides, Fire Scale and Flux Residue with Haz-Mat’s. Cyanide Bombing - Jewelry with deep recesses is cleaned in a solution of 10% liquid potassium cyanide and 35% hydrogen peroxide. Pickling Cleaning - Jewelry with minor recesses is cleaned in a solution of 10% Hydrochloric Acid. Electrocleaning - Jewelry is cleaned in a Pyrex glass using a solution of NaCO 4, NaOH, KCn with a 6V charge.

Jewelry Manufacturing Process Step 8 - Alternative Cleaning without Haz-Mat’s. Ultrasonic Units - Electrical unit with soap and water mixture. Electricity is converted to sound waves and the bubbles created, cleans the jewelry. Magnetic Tumblers - Electrical units with metal shot and magnets. The metal shots vibrate and spin and cleans the jewelry.

Jewelry Manufacturing Process Step 9 - Polishing. Electrical unit with a felt wheel or lap wheel, which removes emery marks. Tripoli and Rouge add lustrous shines

Jewelry Manufacturing Process Deep Recess Jewelry

Sampling & Survey Project In 2003, DTSC, UCI, and LACo CUPA conducted haz-waste sampling of jewelry manufacturing buildings. Swab samples were collected from walls and equipment. Solid samples were collected from polishing dusts, sludges, and investment materials. Liquid samples were collected from cleaning and pickling solutions.

Sampling results from Buffing, Polishing, and Grinding Dusts The following metals exceeded regulatory levels for hazardous wastes:  Copper  Nickel  Zinc  Silver  Arsenic  Cadmium  Selenium  Barium.

Sampling results from Investment Wastes Copper and nickel exceeded the regulatory metals for hazardous waste, but not consistently. Therefore, investment wastes are not confidently classified as hazardous

Sampling results from Pickling Solutions Copper, Cadmium, Nickel, Zinc, Chromium and lead was consistently detected above the hazardous waste levels

Sampling results from Ultrasonic Cleaning Elevated Copper, Chromium, Lead, and Silver levels confirmed that spent solutions from ultrasonic cleaning is a hazardous waste.

Sampling results from Acid Cleaning Elevated Cadmium, Chromium, Copper, Nickel, Lead, and Zinc exceeded hazardous waste regulatory levels. The pH of 2 deems the spent acid cleaner to be a hazardous waste.

Sampling results from Cyanide Bombing 97% of the cyanide is consumed in the process of removing fire scale. Elevated copper deems the waste solution to be hazardous waste.

Sampling results from Influent Wastes to basement Treatment Units The following hazardous waste characteristics were tested: pH, metals, and cyanide. The waste was not deemed to be hazardous; because the waste was commingled and diluted.

Sampling results from Sludge captured at the Treatment Unit Copper and Nickel exceeded the hazardous waste regulatory levels.

Conclusions Hazardous waste is produced by polishing, cleaning, stripping or cyanide bombing. Manifests required for spent stripping and cyanide bombing solutions. The solid waste streams meet the definition of a “Excluded Recyclable Material”, because of the high value of Gold, which is refined and recycled. Bill of lading / Refining receipts required for polishing dust, floor sweeps, and also solid waste of tumbling and ultra sonic cleaners.

Jewelry Manufacturing Questions / Comments