Transcript Training - Calcupa

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:
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Precious stone sales.
Precious stone setters.
Jewelry sales.
Jewelry repair.
Jewelry manufacturing.
Jewelry manufacturing equipment sales.
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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.
Pieces are
cut from sprue.
Cyanide
Soldering
Grinding
Polishing
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 NaCO4, NaOH, KCn with a 6V charge.
Jewelry Manufacturing
Process
Step 8 - Alternative Cleaning without Haz-Mat’s.
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.
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.
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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
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Questions / Comments