scholarly journals Specific Mixing Energy of Cemented Paste Backfill, Part I: Laboratory Determination and Influence on the Consistency

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1165
Author(s):  
Reagan Kabanga Dikonda ◽  
Mamert Mbonimpa ◽  
Tikou Belem
Keyword(s):  
Mixing Time ◽  
Companion Paper ◽  
Cemented Paste Backfill ◽  
Practical Applications ◽  
Power Meter ◽  
Mixing Energy ◽  
Mixing Parameters ◽  
Paste Backfill ◽  
Semi Empirical ◽  
Load Mass

Slump determination is widely used to assess the consistency and transportability of fresh cemented paste backfill (CPB). CPB consistency can depend on the mixing procedure for CPB preparation. In this paper, a method was developed to determine the specific mixing energy (SME) that is dissipated during the preparation of CPB mixtures and to analyze its effect on CPB consistency. For this purpose, CPB recipes were prepared using two tailings and the mixing parameters (mixing time and speed and load mass) were successively varied. SME was determined for each mixture using a power meter equipped with an energy recording system mounted on a laboratory Omcan mixer. Slump was also determined for each mixture. A semi-empirical model was then developed to predict SME as a function of the mixing parameters. Results showed that predicted SME compared well with measured SME during CPB preparation. Results also showed that slump increased with increasing SME. The influence of SME on the rheological and mechanical properties of CPB and practical applications are presented in a companion paper.

scholarly journals Specific Mixing Energy of Cemented Paste Backfill, Part II: Influence on the Rheological and Mechanical Properties and Practical Applications

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1159
Author(s):  
Reagan Kabanga Dikonda ◽  
Mamert Mbonimpa ◽  
Tikou Belem
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Yield Stress ◽  
Specific Energy ◽  
Distribution System ◽  
Flow Index ◽  
Cemented Paste Backfill ◽  
Practical Applications ◽  
Mixing Energy ◽  
Paste Backfill

The rheological properties (yield stress, flow index and infinite dynamic viscosity) and mechanical properties (unconfined compressive strength, UCS) of different cemented paste backfill (CPB) recipes must be determined during the laboratory optimization phase. However, the influence of the mixing procedure on these properties has scarcely been studied so far. The objective of this paper is to assess to what extent these properties depend on the specific mixing energy (SME) for a given type of mixer. CPB recipes were prepared based on two types of tailing (CPB-T1 and CPB-T2, also referred to as T1 and T2) at a fixed solid percentage for each type of tailing using the Omcan laboratory mixer. A mixture of 80% slag and 20% GU was used as a binder. The mixing time and the rotation speed of the mixer were successively varied. For each recipe prepared, we determined the SME, the rheological properties of fresh CPB (at the end of mixing) and the UCS at 7, 28 and 90 days of curing. The results show that yield stress and infinite viscosity decreased when SME increased in an interval going from 0.3 to 3.8 Wh/kg and 0.6 to 6 Wh/kg for CPB-T1 and CPB-T2, respectively. An increasing trend in UCS with increasing SME was also observed. Empirical equations describing the change of the rheological properties with the SME are used to estimate the change in rheological properties of CPB along the distribution system, considering the specific energy dissipation during CPB transportation. A mixing procedure for obtaining CPB mixtures that are representative of CPB deposited in underground mine stopes is suggested for laboratories who currently use a same mixing procedure, irrespective of the variable field specific energy.

Effect of mixing time on hydration kinetics and mechanical property of cemented paste backfill

2020 ◽  
Vol 247 ◽  
pp. 118516
Author(s):  
Liuhua Yang ◽  
Hongjiang Wang ◽  
Aixiang Wu ◽  
Hong Li ◽  
Tchamba Arlin Bruno ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Mixing Time ◽  
Cemented Paste Backfill ◽  
Hydration Kinetics ◽  
Paste Backfill

Effects of temperatures and pH values on rheological properties of cemented paste backfill

2021 ◽  
Vol 28 (6) ◽  
pp. 1707-1723
Author(s):  
Qin-li Zhang ◽  
Yi-teng Li ◽  
Qiu-song Chen ◽  
Yi-kai Liu ◽  
Yan Feng ◽  
...  
Keyword(s):  
Rheological Properties ◽  
Cemented Paste Backfill ◽  
Ph Values ◽  
Paste Backfill

Recycling flue gas desulfurisation gypsum and phosphogypsum for cemented paste backfill and its acid resistance

2021 ◽  
Vol 275 ◽  
pp. 122170
Author(s):  
Shiyu Zhang ◽  
Yingliang Zhao ◽  
Hangxing Ding ◽  
Jingping Qiu ◽  
Zhenbang Guo
Keyword(s):  
Flue Gas ◽  
Acid Resistance ◽  
Cemented Paste Backfill ◽  
Paste Backfill

scholarly journals Strengthening Behavior of Cemented Paste Backfill Using Alkali-Activated Slag Binders and Bottom Ash Based on the Response Surface Method

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 855
Author(s):  
Qi Sun ◽  
Xueda Wei ◽  
Tianlong Li ◽  
Lu Zhang
Keyword(s):  
Response Surface ◽  
Bottom Ash ◽  
Hydration Product ◽  
Cemented Paste Backfill ◽  
Alkali Activated Slag ◽  
Surface Method ◽  
Optimal Mix ◽  
Paste Backfill ◽  
Activated Slag ◽  
Alkali Activated

A new type of cemented paste backfill (CPB) was prepared by using the bottom ash (BA) from a thermal power plant as an aggregate, alkali-activated slag as a binder, and an air-entraining agent as an admixture. Based on the central composite design (CCD) response surface method, the mix ratio was optimized, and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) was performed on the optimal mix ratio. ImageJ software was utilized to determine the porosity of the experimental samples at various curing ages. The results indicate that the optimal mix ratio of the aggregate-binder ratio is 3.28, the alkali dosage is 3%, the solid content is 67.44%, and the air-entraining agent dosage is 0.1%. As the curing age increases, the porosity of CPB gradually decreases. A calcium aluminosilicate hydrate (C-A-S-H) gel is the main hydration product of alkali-activated slag. At the beginning of the hydration reaction, the slag gradually dissolves, and the C-A-S-H product binds the BA together. At 14 d, complete calcium hydroxide (CH) crystals appeared in the hydration product. Finally, the degree of C-A-S-H crystallization increased further to form a dense structure.

Sign in / Sign up

Export Citation Format

Share Document