The Jewelry Manufacturing Industry

1
The Jewelry Manufacturing Industry
Fernando Florez Supervising Haz-Mat
Specialist LA Co. CUPA
2
Introduction

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

3
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.

4
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.

5
Jewelry ManufacturingProcess

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

6
Jewelry ManufacturingProcess
Step 1 - Jeweler conceptualizes and creates a
master original piece.
7
Jewelry ManufacturingProcess
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.
8
Jewelry ManufacturingProcess
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.
9
Jewelry ManufacturingProcess
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.
10
Jewelry ManufacturingProcess
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.
11
Jewelry ManufacturingProcess
Step 6 - Devestment.
Cast cylinder is washed to remove the jewelry
sprue from the plaster.
Sprue Tree is ready for individual piece removal.
12
Jewelry ManufacturingProcess
Step 7 - Jewelry Pieces are Cut From Sprue Tree
and Soldered, Grind and Polished.
13
Jewelry ManufacturingProcess
Step 8 - Cleaning and Removal of Oxides, Fire
Scale and Flux Residue with Haz-Mats.
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 NaCO4, NaOH, KCn with a
6V charge.
14
Jewelry ManufacturingProcess
Step 8 - Alternative Cleaning without Haz-Mats.
Magnetic Tumblers - Electrical units with metal
shot and magnets. The metal shots vibrate and
spin and cleans the jewelry.
Ultrasonic Units - Electrical unit with soap and
water mixture. Electricity is converted to sound
waves and the bubbles created, cleans the jewelry.
15
Jewelry ManufacturingProcess
Step 9 - Polishing.
Electrical unit with a felt wheel or lap wheel,
which removes emery marks. Tripoli and Rouge
add lustrous shines
16
Jewelry ManufacturingProcess
Deep Recess Jewelry
17
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.

18
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.

19
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

20
Sampling results from Pickling Solutions

• Copper, Cadmium, Nickel, Zinc, Chromium and lead
  was consistently detected above the hazardous
  waste levels

21
Sampling results from Ultrasonic Cleaning

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

22
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.

23
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.

24
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.

25
Sampling results from Sludge captured at the
Treatment Unit

• Copper and Nickel exceeded the hazardous waste
  regulatory levels.

26
(No Transcript)
27
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.

28
Jewelry Manufacturing

• Questions / Comments