Research on the Influence of Gypsum and Anhydrite Stone Impurities on the Properties of the Binder

Gypsum (CaSO4 2H2O) and anhydrite (CaSO4) are the most common sulfate minerals. The predominant part of gypsum and anhydrite is used as raw materials for the production of gypsum binders (construction gypsum) and additives in various types of cements, to a lesser extent–for the production of hard-burnt, high-strength, molding and medical gypsum, sulfuric acid, ammonium sulfate, and paper and for soil gypsuming. In addition, gypsum and anhydrite are used in small quantities as decorative and ornamental materials. In each deposit of natural gypsum, the distinctive features are its composition and structure, which directly affects the production conditions and construction and technical properties of gypsum binders. This paper is aimed at evaluating the influence of various impurities present in gypsum and anhydrite stones on the properties of the binder. In this work, the selected samples for each case were subjected to chemical and mineralogical analysis, passed the roasting stage, and then samples-beams are formed and tested for bending and compression on laboratory equipment. In summary, the conclusion was made about the ability of impurities to influence the indicators of setting time, strength values.