INTERNATIONAL CLEANER PRODUCTION INFORMATION CLEARINGHOUSE

Case Study #270

1. Headline: Process modification in a crystal and glass

works reduces discharge

2. Background: The Art de Vianne crystal and glass works

produces glass and crystal lighting by blowing. A

technical feasibility study on the fluoridated bath

recycling for the satin finish for glass was carried out

in 1993.

3. Cleaner Production Principle: process modification

4. Description of Cleaner Production Application:

Information about the process and wastes

The glass is given a satin finish and frosted by soaking

in a fluorhydric acid and ammonium bifluoride bath. The

rinsing waters contain hexafluorosilicic acid, ammonia,

silica and fluorohydric acid. The factory did not have any

waste treatment.

The technique normally used by the glass workers consists

of precipitation-settling-filtration with lime milk which

generates sludge, costly to discharge. The sanitary land

filling of such sludge will be forbidden in the future.

The study was concerned with a regeneration process for

effluent solutes to obtain fluorohydric acid, satin finish

recycling and recycling of treated rinsing water.

The process is based on electrodialysis and

electrometathesis.

Decomposition of hexafluorosilicic acid by strong

alkaline.

Elimination of the silica achieved by filtration.

Preconcentration of ammonium fluoride achieved in a

preliminary electrodialysis module.

Concentration of fluorohydric acid in a second

electrodialysis module.

Recycling of the thinned solution, towards the rinsing,

and of the solution concentrated in fluorohydric acid

towards the satin-finish bath.

Stage of development

Study started on a pilot unit of 1 m3/h to validate the

concluding results obtained in the laboratory.

Material / energy balance and substitution

Recuperation forecast of 30 tons of fluoride per year.

Recuperation forecast of 5 kg of fining products per year.

5. Economics:

Cost of direct investment

Technical study 656 000

Financial study 144 000

Total 800 000

FF (1993)

6. Advantages:

Discharges suppression.

Reduction of pollution tax.

Conformity of the factory to environmental regulations.

Products saving.

7. Constraints: No information provided.

8. Contacts:

Agence de l'Eau Adour-Garonne

M. GARIADOR

TEL: 33 61.36.37.38

M. PARENT

S.A. Cristalleries et Verreries d'Art de Vianne

Le Bourg

47230 VIANNE - France

TEL: 33 53.97.55.05

FAX: 33 53.97.50.28

M. Maton

M. Chatenet

Office International de l'Eau

Direction de la Formation et des Etudes

rue Edouard Chamberland

87065 Limoges Cedex, France

TEL: 33 55114770

FAX: 33 55777115

9. Keywords: France, crystal and glass, lighting, process

modification, fluoridated bath, electrometathesis, ISIC

3620, electrodialysis

10. This case study was submitted to UNEP IE in 1994 by the

French Office International de l'Eau. It has not undergone

a formal technical review.