Influence of Additve on Over-Sulfur Phosphogypsum-Ground Granulate Blast-Furnace Slag Cement

2015 ◽  
Vol 744-746 ◽  
pp. 1431-1434
Author(s):  
Zhi Jiang Lv ◽  
Zong Shou Lin ◽  
Ya Han ◽  
Hao Jie Wang

The effect of sodium hydroxide (NaOH) and polycarboxylate superplasticizer amount on over-sulfur phosphogypsum–ground granulate blast-furnace slag cement was investigated. The mechanical performances and hydration mechanism of the cement with different proportions of NaOH and polycarboxylate superplasticizer (BASF) were analyzed based on setting time, the additive quantity of water, strength test, XRD and SEM analyses. The results showed that the polycarboxylate superplasticizer, can increase the densification and the strength of the cement ,to improve the performance of the cement anti-carbonation properties. NaOH as an alkali activator significantly reduces the cement setting time and improves the cement early strength. But the acceleration of hydration process produces coarse crystalline hydration products and the osteoporosis structure of hardened paste, which has a negative effect on long term strength.

2014 ◽  
Vol 638-640 ◽  
pp. 1453-1459
Author(s):  
Zhi Jiang Lv ◽  
Zong Shou Lin ◽  
Hao Jie Wang

Over-sulfur phosphogypsum(PG)–ground granulate blast-furnace slag(GGBFS) cement paste is utilized by GGBFS, Portland cement clinker(PCC), additive, water and modificated phosphogypsum paste(MPG), produced by milling PG mixed with a certain proportion of steel slag(SS), GGBFS and water. The effect of PG on the properties of over-sulfur PG– GGBFS cement was investigated. The mechanical performances and hydration mechanism of the cement with different kinds, proportions and particle size of PG were analyzed based on setting time, volume stability, strength test, XRD and SEM analyses. The experimental results show that,the optimum mixture of PG amount in the binder was 45%. Overdose of PG may caused strength deterioration. The optimum grinding time of MPG in the binder was 20min. The soluble phosphorus content of PG in the binder was under 0.05%.


2017 ◽  
pp. 80-85
Author(s):  
V. P. Ovchinnikov ◽  
O. V. Rozhkova ◽  
N. A. Aksenova ◽  
P. V. Ovchinnikov

In the article studies of oil-filled compositions with the addition of blast-furnace slag for strength at elevated temperatures are presented. The rheological parameters of the slag cement slag cement mortar, as well as the setting time, were studied. Conclusions are drawn about the prospects of further study of slag cementcontaining compositions.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 382 ◽  
Author(s):  
Danying Gao ◽  
Zhenqing Zhang ◽  
Yang Meng ◽  
Jiyu Tang ◽  
Lin Yang

This work aims to investigate the effect of additional flue gas desulfurization gypsum (FGDG) on the properties of calcium sulfoaluminate cement (CSAC) blended with ground granulated blast furnace slag (GGBFS). The hydration rate, setting time, mechanical strength, pore structure and hydration products of the CSAC-GGBFS mixture containing FGDG were investigated systematically. The results show that the addition of FGDG promotes the hydration of the CSAC-GGBFS mixture and improves its mechanical strength; however, the FGDG content should not exceed 6%.


2019 ◽  
Vol 95 ◽  
pp. 19-24 ◽  
Author(s):  
Junxiang Liu ◽  
Qingbo Yu ◽  
Zongliang Zuo ◽  
Fan Yang ◽  
Zhicheng Han ◽  
...  

2018 ◽  
Vol 149 ◽  
pp. 01012 ◽  
Author(s):  
Leonid Dvorkin ◽  
Nataliya Lushnikova ◽  
Mohammed Sonebi

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.


2017 ◽  
Vol 71 (1) ◽  
pp. 308-314
Author(s):  
Shingo YOSHIMOTO ◽  
Tatsuo SHINMI ◽  
Hiroyoshi KATO ◽  
Takatoshi MOTOORI

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