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1

Optimization of the energy distribution of SABC circuits

Gong D., Nadolski S., Sun C., Klein B., Kou J.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 4

1245--1252

EN

Improving the energy efficiency of large grinding mills is of great importance to reduce the energy cost of mineral processing. The ratio of SAG mill to ball mill’s energy consumption varies greatly among SABC operations. Thus far, very few research studies have been conducted to demonstrate how the SAG mill or ball mill responses to the change of circuit energy distribution in terms of comminution efficiency. The present study investigated the energy performance of an operating SABC circuit at variable circuit energy distributions. An energy benchmarking model was used to assess the comminution energy efficiency of SAG mill, ball mill, and overall circuit. It is found that the target SABC circuit achieves the highest overall energy efficiency when 37.6% of the total circuit energy is distributed to the SAG mill and 62.4% to the ball mill. The maximum energy efficiency of this SABC circuit is approximately 25% when compared to the minimum practical energy required to carry out an equivalent comminution duty. The study also showed that the ball mill is more sensitive to the variation in circuit energy distribution than the SAG mill.

2

Remote pipeline pumping transportation of cemented tailings backfill slurry

Xiao S., Liu Z., Jiang Y., Li C., Sun C., Su L.

Archives of Mining Sciences

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2018

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Vol. 63, no. 3

647--663

EN

For most precious metal mines, cemented tailings backfill slurry (CTBS) with different cement-sand ratio and solid concentration are transported into the gobs to keep the stability of the stope and mitigate environmental pollution by mine tailing. However, transporting several kinds of CTBS through the same pipeline will increase the risk of pipe plugging. Therefore, the joint impacts of cement-sand ratio and solid concentration on the rheological characteristics of CTBS need a more in-depth study. Based on the experiments of physical and mechanical parameters of fresh slurry, the loss of pumping pressure while transporting CTBS with different cement-sand ratio, flux and solid mass concentration were measured using pumping looping pipe experiments to investigate the joint impacts of cement-sand ratio and solid concentration on the rheological characteristics of CTBS. Meanwhile, the effect of different stopped pumping time on blockage accident was revealed and discussed by the restarting pumping experiments. Furthermore, Fluent software was applied to calculate the pressure loss and velocity distribution in the pipeline to further analysis experimental results. The overall trends of the simulation results were good agreement with the experiment results. Then, the numerical model of the pipeline in the Sanshandao gold mine was conducted to simulate the characteristics of CTBS pipeline transportation. The results show that the pumping pressure of the delivery pump can meet the transportation requirements when there is no blockage accident. This can provide a theoretical method for the parameters optimizing in the pipeline transportation system.

PL

W większości kopalń metali szlachetnych zawiesina zawierająca odpady poflotacyjne wraz z cementem w różnych proporcjach cementu i piasku oraz o różnym stężeniu części stałych transportowana jest do wyrobisk i zrobów, gdzie wykorzystywana jest następnie do stabilizacji w rejonie przodka, ponadto w ten sposób ogranicza się zanieczyszczenie środowiska odpadami poflotacyjnymi. Jednakże przetłaczanie różnych rodzajów zawiesin w tym samym układzie rurociągu zwiększa ryzyko zaczopowania rur. Zbadanie wpływu proporcji cementu do piasku w zawiesinie oraz stężenia części stałych na charakterystykę reologiczną zawiesiny wydaje się kwestią kluczową. W oparciu o badania eksperymentalne fizycznych i mechanicznych parametrów świeżej zawiesiny, dokonano pomiarów spadku ciśnienia pompowania w trakcie przetłaczania zawiesin o zawartości cementu i pisaku w różnych proporcjach, dla różnych natężeń przepływu i stężeń części stałych w eksperymentach z wykorzystaniem linii obiegowej rurociągu. Celem eksperymentu było określenie łącznego wpływu proporcji cementu do piasku oraz stężenia części stałych na właściwości reologiczne zawiesiny. Ponadto, przeanalizowano w jaki sposób długość przerw w procesie przetłaczania wpływa na zwiększenie ryzyka zatkania rur i przeprowadzono eksperymenty polegające na wznowieniu pracy pomp. Analizę wyników eksperymentów uzupełniono poprzez zastosowanie oprogramowania Fluent do obliczenia spadku ciśnienia w rurociągu oraz rozkładu prędkości. Wykazano, że wyniki symulacji pozostawały w dużej zgodności z wynikami eksperymentów. W kolejnym kroku opracowano model numeryczny rurociągu eksploatowanego w kopalni złota Sanshandao dla potrzeb symulacji procesu przetłaczania zawiesiny. Uzyskane wyniki wskazują, że ciśnienie tłoczenia w pompie jest na wymaganym poziomie gdy nie występuje zablokowanie przepływu w rurze, i wykorzystane być mogą jako uzupełnienie teoretycznych metod optymalizacji parametrów układu transportowania i przetłaczania zawiesiny.

3

Prediction about ground hardening layers distribution on grinding chatter by contact stiffness

Sun C., Duan J., Lan D., Liu Z., Xiu S.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 4

1626--1642

EN

The grinding hardening is an integrated manufacturing technology which combines the surface hardening theory and the grinding technology. However, the grinding chatter accompanies with the whole grinding hardening process. It is the existence of the grinding chatter that makes the transformation unsteady. To this end, the paper presents a three-hybrid model to investigate the relationship between the grinding chatter and the grinding hardening layers distribution. The dynamic grinding force with the analytic and numerical method is calculated firstly. Then the finite difference method (FDM) is used to obtain the dynamic temperature distribution accordingly. Thirdly, the cellular automata (CA) method is applied to calculate the transformed microstructure distribution under different chatter strengths. The study shows that the thickness of the grinding hardening layers goes up with the increase of the grinding chatter. However, the quality of the grinding hardening layers reduces with the increase of the chatter strength. In addition, the martensite content varies with different hardening layers since each layer has its own unique temperature distribution. Moreover, metallurgical experiments are conducted to validate the proposed model. The model is anticipated to be meaningful for the improvements of workpiece's mechanical properties by controlling the chatter strength in the industry manufacturing.

4

Selective adsorption of anionic polyacrylamide onto ultra-low ash coal and kaolinite

Zou W., Yu C., Sun C., Cao Y.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 2

738--753

EN

To study the selectivity of polyacrylamide in the selective floc flotation of fine coal, adsorption of anionic polyacrylamide (PAM A401) onto ultra-low ash coal and kaolinite was studied, including the adsorption thermodynamics, floc size distribution and wettability changes. The thermodynamics of the adsorption process at the low concentration of 0-16 mg/dm3 of PAM A401 were studied at different contact times, doses, temperatures and pH values. Thermodynamic parameters of ΔGo, ΔHo, ΔSo and Ea were evaluated to understand the nature of the adsorption process. The results indicated that PAM A401 was selectively adsorbed onto ultra-low ash coal rather than kaolinite. Physical adsorption was the predominant mechanism, and the adsorption of PAM A401 at 12 mg•dm-3 onto coal was 2.15-fold larger than the adsorption on kaolinite. After the adsorption of PAM A401, the lipophilic hydrophilic ratio (LHR) of coal decreased from 9.23 to 7.28, indicating that the coal became less hydrophobic than before. In contrast, the LHR of kaolinite increased from 1.44 to 1.65. Floc size measurements showed that the d10, d50 and d90 of coal flocculated by PAM A401 (at 12 mg/dm3, pH 6.5) were 3.18, 2.76 and 2.59-fold greater than the corresponding levels of these parameters for kaolinite flocs, respectively.

5

A Signal Subspace Speech Enhancement Approach Based on Joint Low-Rank and Sparse Matrix Decomposition

Sun C., Xie J., Leng Y.

Archives of Acoustics

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2016

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Vol. 41, No. 2

245--254

EN

Subspace-based methods have been effectively used to estimate enhanced speech from noisy speech samples. In the traditional subspace approaches, a critical step is splitting of two invariant subspaces associated with signal and noise via subspace decomposition, which is often performed by singular-value decomposition or eigenvalue decomposition. However, these decomposition algorithms are highly sensitive to the presence of large corruptions, resulting in a large amount of residual noise within enhanced speech in low signal-to-noise ratio (SNR) situations. In this paper, a joint low-rank and sparse matrix decomposition (JLSMD) based subspace method is proposed for speech enhancement. In the proposed method, we firstly structure the corrupted data as a Toeplitz matrix and estimate its effective rank value for the underlying clean speech matrix. Then the subspace decomposition is performed by means of JLSMD, where the decomposed low-rank part corresponds to enhanced speech and the sparse part corresponds to noise signal, respectively. An extensive set of experiments have been carried out for both of white Gaussian noise and real-world noise. Experimental results show that the proposed method performs better than conventional methods in many types of strong noise conditions, in terms of yielding less residual noise and lower speech distortion.

6

Synthesis of polyaniline nanotubes through UV light catalytic method

Sun C., Wang Y.

Materials Science Poland

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2015

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Vol. 33, No. 1

193--197

EN

In this study, nitrocellulose (NC) fiber blanket prepared by electrostatic spinning method has been used as a template, and copper nitrate (Cu(NO3)2)) as an oxidant to synthesise polyaniline nanotubes doped with heteropolyacid (H4)SiW12)O40), SiW12) using UV light catalytic method. Infrared spectroscopy (IR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) technologies were applied to characterize the prepared samples of polyaniline nanotubes. The results show that the external diameter of the tube is about 200 nm, and the internal diameter about 170 nm. We also give a reasonable speculation and explanation about the formation mechanism of the nanotubes.

7

Synthesis and characterization of graphene oxide composite with Fe3O4

Sun C., Wang Y.

Materials Science Poland

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2015

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Vol. 33, No. 3

488--490

EN

In the paper, a magnetic composite of graphene oxide (MGO) has been successfully synthesized through decomposition of iron (III) acetylacetonate in the mixture solution of triethylene glycol and graphene oxide (GO). Atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and superconducting quantum interference device were used to characterize the material. The results show that the magnetic Fe3O4 nanoparticles modified graphene oxide composite with superparamagnetic properties, and magnetization saturation of 16.4 emu/g has been obtained. The MGO has a good sustained-release performance, and in vitro cytotoxicity confirming its secure use as a potential drug carrier.

8

Maintenance strategy decision for avionics system based on cognitive uncertainty information processing

Tu J., Sun C., Zhang X., Pan H., Cheng R.

Eksploatacja i Niezawodność

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2015

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Vol. 17, no. 2

297--305

EN

Proper maintenance schedule is required to improve avionics systems reliability and safety. A decision approach to maintenance strategy remains a longstanding challenge in avionics system. With regard to fault diagnosis and equipment maintenance of avionics system, in which the equipment fault information are complex and uncertainty, a multi criteria of decision making method for avionics system based on cognitive uncertainty information processing is proposed to be used in the maintenance strategy decision. Firstly, vague set with three-parameters is introduced to make up for the shortage of the original vague set in expressing fuzzy information, a linguistic variables describing the qualitative indexes into three parameter vague of interval number is proposed. At the same time, due to risk psychological factors of maintenance policymakers that cause cognitive uncertainty are introduced into the maintenance decision process, and a prospect value function of three parameters vague interval value is defined based on prospect theory and the formula for measuring the distance between vague interval value, and a non-linear model of equipment maintenance policies can be established. The implementing process of maintenance policy decision for avionics system based on cognitive uncertainty information processing is given in this paper, and a ranking of the maintenance alternatives is determined. Finally, A specific example of decision of maintenance strategies in avionics system with the application of the proposed method is given, showing that the reliability centered maintenance strategy is the most suitable for avionics system.

PL

Doskonalenie niezawodności i bezpieczeństwa układów elektroniki lotniczej wymaga odpowiedniego harmonogramu działań obsługowych. Podejście decyzyjne do strategii utrzymania ruchu od dawna pozostaje wyzwaniem w systemach awioniki. W odniesieniu do diagnozy uszkodzeń i konserwacji urządzeń systemów elektroniki lotniczej, w których informacje o usterkach urządzeń są złożone i obarczone niepewnością, zaproponowano metodę wielokryterialnego podejmowania decyzji opartą na przetwarzaniu informacji związanych z niepewnością kognitywną, którą można stosować przy podejmowaniu decyzji dotyczących strategii utrzymania ruchu. Po pierwsze, wprowadzono nieostry zbiór trzech parametrów, które pozwalają na wyrażenie wartości liczbowej zaproponowanych zmiennych lingwistycznych opisujących wskaźniki jakościowe, jako wartości z przedziału nieostrego. Jednocześnie, do pojęcia procesu decyzyjnego dotyczącego utrzymania ruchu wprowadzono pojęcie ryzyka związanego z powodującymi niepewność poznawczą czynnikami psychologicznymi kierującymi osobami podejmującymi decyzje obsługowe. Zdefiniowano także funkcję oceny dla wartości z przedziału nieostrego trzech parametrów na podstawie teorii perspektywy i wzór do pomiaru odległości między wartościami z przedziału nieostrego, oraz ustalono nieliniowy tryb polityki konserwacji sprzętu. W artykule zaprezentowano proces implementacji decyzji w zakresie polityki konserwacji układów elektroniki lotniczej w oparciu o przetwarzanie informacji związanych z niepewnością kognitywną, stworzono też ranking dostępnych alternatyw w zakresie utrzymania ruchu. Na koniec, zaprezentowano konkretny przykład decyzji w zakresie strategii konserwacji układów elektroniki lotniczej z zastosowaniem proponowanej metody, pokazując, że strategia utrzymania ruchu oparta na niezawodności jest najbardziej odpowiednia dla układów awioniki.

9

Preparation of polyaniline nanostructures doped with different dicarboxylic acids through template-free method

Sun C, Wang Y.

Materials Science Poland

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2014

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Vol. 32, No. 3

419—422

EN

Department of Materials Chemistry, Yinuo Institution, Changchun, 130033, China In this article nanoscaled polyanilines (PANI) were prepared based on template-free method in the presence of dicarboxylic acid dopants (e.g. D-tartaric acid, succinic acid, maleic acid and fumaric acid). The trans-cis isomerization of butenedioic acid played an important role in the formation of nanostructures from the plane-like to nanofibers, and the PANI doped with maleic acid (MA) had larger diameter, higher crystallinity and conductivity than PANI doped with fumaric acid (FA).

10

A Method to Estimate Leakage Current of Polluted Insulators

Xia Y., Jiang X., Sun C., Dong B.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 3b

161-164

EN

The effects of the applied voltage(U), equivalent salt deposit density (�PESDD) and relative humidity density(RH) on the leakage current (LC) are studied based on the least squares algorithm (LSA) in this study. Experiments' results show that, the maximal amplitude of LC Ih increases with the increase of �PESDD by an power function with a positive index 0.451, while increases with the increase of both U and RH by an exponential function with a positive index 0.017 for U and 9.751 for RH. The result can be used to evaluate the pollution condition of insulators based on LC.

PL

Zbadano prąd upływu zabrudzonych izolatorów uwzględniając przyłożone napięcie, względne zasolenia i względna wilgotność. Stwierdzono, że prąd upływu rośnie wraz z zasoleniem ze współczynnikiem potęgowym 0.45.

11

Nowe katalizatory procesów wodorowych. Hydroodazotowanie karbazolu na azotku molibdenu

Stańczyk K., Miga K., Fabiś G., Sun C.

Przemysł Chemiczny

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1998

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T. 77, nr 3

95-97