A NEW APPROACH TO THE DESALINATION PROCESS OF ARCHAEOLOGICAL POTTERIES

Abstract

As salt crystallization is one of the most serious damages in historical porous materials (e.g. potteries, bricks,

etc.), desalination is highly important process in conservation. Since this process is irreversible, and object

has direct vicinity with water, preventing the misrepresentation of valuable archaeological and archaeomet

rical data of historic object will be substantial. On the other hand, a considerable amount of water is used in

this process because of a huge number of excavated potteries in archaeological sites, therefore, controlling

the amount of rinse water consumption is extremely desirable. As this process is a multivariable system, a

new approach based on a mathematical design of experiment, response surface methodology (RSM), was

used as a n aid in determining the significance of the various parameters and optimization of this process.

The input (independent) variables in the experimental design were immersing time, agitation rate, firing

temperature (as void fraction indicator), type and concentration of surfactant. For each variable, five levels

were selected in a batchwise pilot tests. Electrical conductivity (EC) and Ca2+ concentration of rinse solutions

were measured as responses of experiments. It was found that the most effective parameters in the immers

ing desalination process are: firing temperature of specimen, immersing time, and agitation rate. The exper

imental results revealed that desalination process in optimized conditions results in speed up the operation

time up to less than 8% and saving up to 50% water consumption compared to conventional method at the

same desalination achievement. The accuracy of the modeling was validated with triplicate experiments. It

was found that the average Ca2+ concentration and EC value in rinse solution fit approximately 90% with

RSM predicted data.