Experiments and Optimization of Mix Proportions for Cement Paste Backfill Materials with Extra-Fine Unclassified Tailings

2017 ◽  
Vol 744 ◽  
pp. 146-151
Author(s):  
Ming Qing Huang ◽  
Xiao Hui Liu ◽  
Hai Yong Cheng
Keyword(s):  
Cement Paste ◽  
Mass Concentration ◽  
Influential Factors ◽  
Range Analysis ◽  
Bleeding Rate ◽  
Orthogonal Experiments ◽  
Optimal Mix ◽  
Backfill Materials ◽  
Unclassified Tailings ◽  
Paste Backfill

To produce effective cement paste backfill materials at iron mines technologically and economically, orthogonal experiments of mix proportions with extra-fine unclassified tailings were carried out. The results of the range analysis showed that the sensitivity of influential factors to the slurry slump is sequentially mass concentration, tailing/rock ratio, and cement/(tailing+rock) ratio. The sensitivity to bleeding rate, concretion time and 28-day uniaxial compressive strength is sequentially mass concentration, cement/(tailing+rock) ratio and tailing/rock ratio. Relationships of paste properties and influential factors can be demonstrated with regression analysis. Additionally, the optimal mix proportion for cement paste backfill was obtained with 78% mass concentration, 7:3 tailing/rock ratio and 1:25 cement/(tailing+rock) ratio. The slump, bleeding rate, concretion time and R28 of the optimal mixture are 25.2 cm, 8.77%, 20.9 h and 1.29 MPa, respectively. The experimental results show a feasible way to produce the industry standard backfilling materials.

scholarly journals A Novel Prediction Model of Strength of Paste Backfill Prepared from Waste-Unclassified Tailings

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Haiyong Cheng ◽  
Shunchuan Wu ◽  
Xiaoqiang Zhang ◽  
Junhong Li
Keyword(s):  
Prediction Model ◽  
Prediction Models ◽  
Orthogonal Design ◽  
Influential Factors ◽  
Waste Rock ◽  
Strength Prediction ◽  
Strength Development ◽  
Local Conditions ◽  
Unclassified Tailings ◽  
Paste Backfill

Paste backfilling is an important support for the development of green mines and deep mining. It can effectively reduce a series of risks of underground goaf and surface tailings ponds. Reasonable strength of backfill is an effective guarantee for controlling ground stress and realizing safe mining function. Under the combination of complex materials and local conditions, ensuring the optimal design and effective proportion for paste backfill strength is the bottleneck problem that restricts the safety, economy, and efficiency of filling mining. The strength developing trend of paste backfilling prepared from waste rock and unclassified tailings has been studied. Different levels of cement contents, tailings-waste ratios, and slurry concentrations were investigated through orthogonal design to obtain the relationship between the UCS and the multi-influential factors. Combined with the experimental results and the previous strength prediction models, the waste rock-unclassified tailings paste strength prediction model was proposed. Introducing the water-cement ratio, the cement-tailings ratio, the amount of cement, and the packing density that characterizing the overall gradation of unclassified tailings and waste rock, as well as the curing time, a strength prediction model of multifactors was developed. Moreover, the microscopic structure of the paste prepared from waste-unclassified tailings was analyzed with an Environment Scanning Electron Microscope (ESEM), and the influence mechanism was ascertained. The weight coefficient of strength development is carded in this paper, and the strength model of unclassified tailings-waste paste considering five factors is obtained, which is of great significance to guide the mining engineering.

scholarly journals Utilization of Foaming Technology in Cemented Paste Backfill of High-Mud Superfine Unclassified Tailings

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Jian-wen Zhao ◽  
Xin-min Wang ◽  
Kang Peng ◽  
Shuai Li
Keyword(s):  
Rheological Parameters ◽  
Cemented Paste Backfill ◽  
Pipeline Transportation ◽  
Bleeding Rate ◽  
Three Phase ◽  
Three Phase Flow ◽  
Unclassified Tailings ◽  
Paste Backfill ◽  
Resistance Loss ◽  
Foaming Technology

Due to high-mud content in superfine unclassified tailings (SUT), the viscosity of cemented paste backfill (CPB) is high and its pipeline transportation properties are poor. Foaming technology was introduced to prepare a new three-phase flow backfill (TFB) using a foaming machine. Then the rheological parameters of TFB with different bubble ratio were measured and their pipeline transportation properties were simulated by Fluent. Besides, the simulation results were further verified by a semi-industrial loop test. The results indicate that the optimum ratio of TFB is a cement-sand ratio of 1 : 8, mass concentration of 70%, and bubble ratio of 20%. Compared with CPB, the decrease of bleeding rate, viscosity, and resistance loss of TFB is 27%, 25%, and 30%, respectively. Therefore, foaming technology is an innovative and feasible solution for high-mud CPB in reducing viscosity, decreasing resistance loss, and improving pipeline transporting efficiency.

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.

The Influence of Various Gypsum Dosage, Specific Area of Cement and Water Reducers on Bleeding of Fresh Cement Paste Using Low-Field NMR

2021 ◽  
Vol 1036 ◽  
pp. 255-262
Author(s):  
Yan Liang Ji ◽  
Zhen Ping Sun ◽  
Min Pang
Keyword(s):  
Cement Paste ◽  
Specific Area ◽  
High Water ◽  
Low Permeability ◽  
Cement Pastes ◽  
Bleeding Rate ◽  
Low Field ◽  
Low Field Nmr ◽  
Type Water ◽  
Hot Zone

Based on the low-field NMR, this study inveitigated bleeding property of the fresh cement pastes mixed with various gypsum dosage, specific area of cement and water reducers. Results showed that the gypsum dosage between 3 % and 5 % will cause an decrease bleeding and a lower bleeding velocity, while a 1 % gypsum dosage will increase the bleeding as a function of time. The increase of the cement surface will lead to a less bleeding rate. This can be explained that the finer particle will contribute to the packing which will form a low permeability of the cement paste, as a result less bleeding water is observed. The PCEs-made sample has smaller hot zone area which indocated the PCEs has good bleeding stability when varing water cement ratio. Furthermore, bying comparing with the NPE, it was found the ACS type water reducer has higher bleeding sensitivity when high water cement ratios were used.

Orthogonal Experiment Study on the Hydrogen Desorption Properties of NaAlH4 and LiAlH4

1994 ◽  
Vol 115-116 ◽  
pp. 1-38 ◽  
Author(s):  
J. van Ek ◽  
A. Lodder
Keyword(s):  
Milling Time ◽  
Orthogonal Experiment ◽  
Weight Ratio ◽  
Hydrogen Desorption ◽  
Experiment Design ◽  
Variance Analysis ◽  
Range Analysis ◽  
Orthogonal Experiment Design ◽  
Optimum Performance ◽  
Orthogonal Experiments

Orthogonal experiment design and variance analysis were adopted to investigate the hydrogen desorption properties of NaAlH4and LiAlH4, which consisted of three stages, ball-milled under argon. Optimum milling condition was very important for the performance of NaAlH4and LiAlH4, which was obtained from the orthogonal experiments. The orthogonal experiment design considered three experimental factors, i.e. weight ratio of ball to power, weight ratio of ɸ8 ball to ɸ4 ball and milling time, which varied on three different levels, respectively. According to the range analysis and variance analysis from the orthogonal experiments, the weight ratio of ball to powder and ɸ8 ball to ɸ4 ball had more impacts on the hydrogen desorption time of NaAlH4,while the most sensitive influencing factor of LiAlH4was milling time. NaAlH4had the optimum performance when the weight ratio of ball to power was 30:1, the weight ratio of ɸ8 ball to ɸ4 ball was 0.5:1 and milling time was 0.5h. LiAlH4had the optimum performance when the weight ratio of ball to power was 40:1, the weight ratio of ɸ8 ball to ɸ4 ball was 0.5:1 and milling time was 2h.

scholarly journals Study of physico-chemical and mechanical characteristics of consolidated and unconsolidated cemented paste backfills

2013 ◽  
Vol 29 (1) ◽  
pp. 81-100 ◽  
Author(s):  
Erol Yilmaz ◽  
Tikou Belem ◽  
Mostafa Benzaazoua
Keyword(s):  
Cement Paste ◽  
Mechanical Characteristics ◽  
Applied Pressure ◽  
Pressure System ◽  
Physico Chemical ◽  
Paste Backfill

Streszczenie W ostatnich latach obserwuje się, że wydajność i jakość próbek zawiesin nasyconych cementem (CPB - Cement Paste Backfill) in situ są stale niższe niż tych samych próbek przygotowanych w plastikowych formach w laboratorium. Może to wynikać z braku w laboratorium skutecznego narzędzia mogącego naśladować zawiesiny in situ, warunki ich utwardzania jak również rozmiary i geometrię próbek. W celu wypełnienia tej luki, w la­boratorium opracowano nowe narzędzie o nazwie CUAPS (Curing Under Applied Pressure System), wytworzone i wykorzystane do zbadania wpływu ciśnienia na podstawie skutecznego nacisku na właściwości fizykochemiczne i mechaniczne CPB, jak również próbek otrzymanych z plastikowych form. Badania porównawcze przeprowa­dzono zarówno dla próbek CUAPS jak i próbek otrzymanych w laboratorium, zawierających lepiszcza (cementu) 3,45 i 7% wag. po 7, 14 i 28 dniach utwardzania. Wyniki wskazują, że wydajność próbek konsolidowanych CUAPS są zawsze bardziej prawdziwe (realistyczne) niż próbek otrzymanych w laboratorium, głównie z powodu odprowadzania wody w wyniku konsolidacji. Ostatecznie metoda CUAPS powoduje korzystny wpływ na utwar­dzenie CPB dzięki zawartości wody (separacja wody od świeżej zawiesiny odpadów z cementu) i połączeniu części wody zasobowej z zawiesiną w zrobach.

Test Analysis of Milling Force of Titanium Alloy Base on MATLAB

2012 ◽  
Vol 499 ◽  
pp. 324-329
Author(s):  
L. Shi ◽  
Z.H. Jiang
Keyword(s):  
Titanium Alloy ◽  
Energy Distribution ◽  
Depth Of Cut ◽  
Milling Machine ◽  
Range Analysis ◽  
Milling Force ◽  
Test Analysis ◽  
Orthogonal Experiments ◽  
Alloy Base ◽  
Radial Depth

Orthogonal experiments of milling titanium alloy TA12 were done on the lifting workbench milling machine. The milling force signals were acquired through PIC-1712 Data Acquired Board. The main frequencies and energy distribution were got through analysis in SPTOOL of MATLAB. The signals were decomposed and reconstructed based on the main frequency of the milling force with wavelet toolbox. The influence of the milling velocity, axial depth of cut and radial depth of cut on the component milling force was got through range analysis. Through analyzing known that three factors had different influence on the component milling force.

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