Application areas of phosphogypsum in production of mineral binders and composites based on them: a review of research results

Abstract

The increase of the consumption of gypsum products in construction industry with a limited amount of natural gypsum deposits requires alternative sources of gypsum-containing raw materials. In some countries which have fertilizers industry plants, the problem can be solved using industrial wastes, e.g. phosphorgypsum – a byproduct of fertilizers’ production. Kept in dumps over decades, phosphorgypsum is subjected to the chemical changes due to washing out impurities with rain and other natural factors. However, there are observed deviations of harmful impurities in dumped PG depending on its age., Phosphorgypsum of any age requires chemical treatment to neutralize remains of phosphorus and sulfuric acids, fluorine compounds. According to our researches one of the most simple and effective method of neutralization the impurities is using lime-containing admixtures. The paper presents results of laboratory tests of phosphorgypsum as a component of clinker and non-clinker binders. There were investigated the impact of phosphorgypsum as admixture for clinker binders to substitute natural gypsum. Neutralized phosphorgypsum can be applied as mineralizing admixture in calcination of Portland cement clinker. Adding 2 to 2.5% of phosphorgypsum as setting time regulator resulted in a similar physical and mechanical properties compared to mix made with natural gypsum. Another important area of phosphorgypsum application is sulphate activatoion of low-clinker blast-furnace slag cement (clinker content is less than 19%). According to results, the incorporation of phosphorgypsum as sulphate activator in cement has the better effect as natural gypsum. Other development has been carried out to modify the phosphorgypsum binder properties. Complex additive consisted of polycarboxylate-based superplasticizer and slaked lime permitted an increase mechanical properties of hardened phosphorgypsum binder due to significant a reduction of water consumption. Such modified binder can be used as partial or complete replacement of gypsum binder for filling cements and finishing plasters. It can substitute gypsum in non-clinker binders like supersulphated cements. There were also developed compositions of supersulphated cements based on low-alumina blast furnace slag and phosphorgypsum. Supersulphated cements were tested in normal-weight and light-weight concrete.

Trends and opportunities of using local sustainable building materials in the Middle East and North Africa region

“…As an alternative source of calcium sulfate-based products, PG can be used to produce modified gypsum binders [69], mineralizing and setting time regulating admixture for cement, binder for supersulphated cement etc. [70].…”

Environmental Problems of Phosphogypsum Utilization

“…The second one. Water-soluble phosphates and fluorides contribute to the formation of the structure of gypsum products with increased strength and water resistance [2,3].…”

Insulation Foam Concrete Nanomodified with Microsilica and Reinforced with Polypropylene Fiber for the Improvement of Characteristics

“…Foam concrete is one of the types of cellular concrete, and this type of concrete belongs to lightweight concrete, and its density can vary from 300 to 1200 kg/m 3 . The structure of this material is characterized by a multitude of randomly arranged air voids, which were formed in the concrete mixture due to the addition of a foaming agent [ 3 , 4 ]. As for the advantages of this material, several researchers [ 5 , 6 , 7 ] noted that foam concrete has properties such as low density and thermal conductivity, this material is also fire resistant, and, due to its porous structure, absorbs sound well.…”