Development and research of the influence of the composition and concentration of activators on the strength of phosphorus slag binders

Ultuar Mahambetova,Bulbul Nuranbayeva,Zatkali Estemesov,Pernekhan Sadykov,Dina Oralbekova,Orken Mamyrbayev

doi:10.15587/1729-4061.2021.242814

Abstract

The paper discusses various ways of activating phosphorus slags by introducing additives for the development of phosphorus slag binders (PSB), replacing cement. Considering that pseudowollastonite is the main mineral of phosphorus slags and without activating components does not possess the binding properties necessary for the production of building materials based on them, we used compositions of small amounts of sodium hydroxide with alkali metal salts, the anions of which form poorly soluble compounds with calcium. When choosing activating components, scarce alkaline additives were replaced by waste from chemical plants, which allows a passing solution of their practical use and environmental problems. The strength at a sodium hydroxide content of 1–4 % after curing of slag samples of various batches was in the range of 50.0–70.0 MPa. Samples of binders of normal hardening at the age of 28 days with a sodium hydroxide content of 0.5; 1.0, 2 and 4 % had the strength of 20.3; 35.4; 45.6; 55.8 MPa, respectively. The effect of the combined presence of alkali and salt is especially noticeable for small amounts of sodium hydroxide. Binders containing a composition of cement with salts under normal conditions and after curing showed a slightly lower strength than in an alkaline medium. With a constant cement content (4 %), the strength indicators increase with an increase in the proportion of the salt additive, reaching at 4 % its maximum value. The effect of the nature of activators on pH was determined. The data obtained indicate the advantages of using PSB and various industrial wastes with a low content of alkaline compounds in the production

Highlights

Granular phosphorous slags are by-products obtained in the production of phosphorus by the method of sublimation in electrothermal furnaces
The aim of the study is the development of highly active perature, high compressive strength of 55 MPa and higher, phosphorus slag binders of hydrothermal and normal hardwhich is explained by the increased total alkali content
The compressive strength of the cement of Kazakhstan), with activating components, neutralizing slurry was reduced by the phosphorus slag from 10 % additives or without them, depending on the field of applicato 50 %, and based on the compressive strength of the ce- tion, were used

Summary

Introduction

Granular phosphorous slags are by-products (manmade) obtained in the production of phosphorus by the method of sublimation in electrothermal furnaces. Their granulation is carried out at a temperature of about. Phosphorus and its compounds (phosphorus fertilizers) are mainly obtained from phosphorite (calcium salt of phosphoric acid Са3(РО4) or 3СаОР2О5), the richest deposits of which in Kazakhstan are located in the Karatau Mountains. The binding properties of monominerals and glasses in the composition of phosphorus slag were studied by [1, 2]. It was found that pseudowollastonite, which is the main mineral of phosphorus slags without activating components does not have astringent properties, but in the presence of calcium hydroxide it acquires them and is able to harden independently

Objectives

Methods

Findings

Conclusion