**1. Introduction**

Developing countries that have accelerated industrialization and urbanization processes are producing billions of tons of waste per year. As a major global ornamental stone producer, Brazil is also a major waste generator, due to the daily extraction of thousands of tons of blocks in quarries. However, much of this type of waste is discarded in an uncontrolled manner, causing environmental problems [1,2].

The waste generated from the extraction and processing of ornamental stones represents around 83% of raw material losses. To produce 330 m<sup>2</sup> of slabs (average from

**Citation:** Agrizzi, C.P.; Carvalho, E.A.S.; Borlini Gadioli, M.C.; Barreto, G.N.S.; de Azevedo, A.R.G.; Monteiro, S.N.; Vieira, C.M.F. Comparison between Synthetic and Biodegradable Polymer Matrices on the Development of Quartzite Waste-Based Artificial Stone. *Sustainability* **2022**, *14*, 6388. https:// doi.org/10.3390/su14116388

Academic Editor: Antonio Caggiano

Received: 30 March 2022 Accepted: 11 May 2022 Published: 24 May 2022

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**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

a 10 m<sup>3</sup> block), approximately 30 m<sup>3</sup> of stone is extracted from the massif, of which 20 m<sup>3</sup> remains in the quarry as waste. Most of them are thick blocks, normally non-standard, irregular, and faulty. In addition, stone chips and hulls from the remaining stocks block rigging, as they can have direct use in the smaller plates, less value tile production, or other structural or decorative pieces [3].

Some of these losses are inevitable, as they are linked to the natural stone quality, the deposit characteristics, or the cutting process. However, they can be reduced by improving deposit knowledge, by mine planning, and, mainly, by transforming the waste generated into by-products [3]. Even though the artificial stone's unit price (m<sup>2</sup> ) and the volume used are relatively high compared to the natural materials, this waste destination, as a by-product, is still the application with the best cost benefit [4].

Artificial stones have aroused the interest of consumers due to certain advantages compared to natural stones. According to data from the Brazilian Association of Dimension Stones Industry—ABIROCHAS, in 2019, Brazilian exports of artificial stones totaled 12.75 thousand tons. Regarding imports, 70,000 tons present average prices of US\$ 530/t and US\$ 1470/t, respectively, while natural stones presented an average price of US\$ 523/t in the same year. Even with a slightly higher price than natural stones, the artificial stone import is much greater than the export [5]. Amongst the advantages of this material are the mechanical and aesthetic properties as well as the use of wastes that reduces irregular disposal, valorizing a traditionally unwanted product, creating jobs, and contributing to economic development [6].
