An Application of Axiomatic Design to Improve Productivity in the Circular Economy Context—The Salt Production Example

Sustainability and a circular economy (CE) are crucial for the development of society. The CE approach should start by designing new products or processes or retrofitting existing ones to achieve the best efficiency and extend their life cycle. Designs that enable CE require the guidance of a design theory. Axiomatic design (AD) theory allows for the classification of designs and achieving the targets if appropriate requirements are adopted. This paper aimed to show that sustainability and productivity can be made compatible by ensuring functional independence, as defined in AD and using the circular economy concept. The paper presents how a salt washing machine could be improved concerning its performance. The analysis of the existing design showed fewer design parameters than the functional requirements. A viable enhancement was the addition of one design parameter, which made it possible to control the separation and washing independently. The resulting machine retrofitting increased the production rate by 20% to 30%—the productivity and the quality of the final product was also improved. The washing process now used less water and energy. Moreover, the brine feeding system was also redesigned, so that the brine was now reused, the land use was reduced as was the operating time, and the operators now worked in a more friendly environment. The industrial case study presented in this paper is an example of how innovative engineering design that fits the design science research (DSR) with the generation of knowledge. The objective of this design solution was to increase the efficiency of the entire process and consequently increase the productivity and sustainability.