Materials Research

EPA Grant Number: R83042001-4

Center: CEER at Alfred University

Investigator: Carty, William M.

Institution: Alfred University

Project Period: May 1, 2006 to April 30, 2007

Research Category: Congressionally Mandated Center

 

Description: 

Pb-containing and Pb-free fritted glazes that contain pigments and colorants are problematic for recycling.  The glazes are difficult to reuse or to re-introduce to the manufacturing process because the colors cannot easily be diluted to an acceptable level.  Efforts to separate pigments and glazes using sedimentation typically fail because the frit and pigment particles have similar or overlapping sedimentation velocities, so hydrocycloning and simple sedimentation are not viable options.  Froth flotation, however, is feasible because it exploits surface chemistry differences and the pigment and frit particles typically have substantially different surface chemistries.  The focus of this research will be to use froth floatation to separate pigments from glaze frit.  The information from this study will allow surfactants to be selected based on the nature of the pigment and frit particles to allow the efficient separation of the these species.  In this way even complex glaze systems can be separated by using a predetermined multi-step floatation process. 

 

Objectives/Hypotheses:

It is theorized that froth flotation can be used to exploit surface chemistry differences between frit and pigment in waste glaze and obtain separation between the components.  In this way components from glaze could be separated, purified and reused in the process.  One goal from this research is to develop a quick method of determining if a system lends itself to froth flotation.  Another goal is to develop a grid that enables one to select the correct chemicals to enable froth flotation and to define the process variables required for any given system. 

 

Approach: 

Materials include Ferro Frit #3124 (as a reasonable example of a typical glaze frit), Mason chrome free black pigment, Mason praseodymium yellow, Sodium Oleate, Dodeclyamine and water.  Instruments to be used include the Galigher Model LA-500 agitator and the Micromeritics Gemini surface area analyzer.  Standard lab equipment such as sieves, distilled water bottles, laboratory weight balances, weighing pans or paper, graduated cylinders, hot plates, beakers, stirring rods and filter paper will be used.

 

Expected Results:

Potential benefits to the environment would be the reduction of waste ceramic glaze that would have to be processed and disposed of into landfills.  The potential reduction in landfill amounts is substantial.  A typical dinnerware manufacturer generates up to 600,000 lbs. of glaze waste per year; roughly 90% of this waste is frit.  It is anticipated that the amount of landfill material from commercial production facilities could be reduced by 80% with a reasonably efficient froth flotation process.  This approach could be applied to both Pb-containing and Pb-free systems with similar efficiency. 

 

Supplemental Keywords: 

Glaze recycling, froth flotation, silicate flotation, ceramic glazes, ceramic manufacturing efficiency, waste reduction.