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1

Hydrochloric acid leaching for upgrading flotation concentrate from a low-grade bauxite ore

Guan C., Chen L., Zheng Y., Sun W., Zheng Y.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

1038--1046

EN

Bauxite is the major raw material for alumina production, and its Al2O3 grade improvement or desilication is a necessary process for production of high-grade alumina concentrates from bauxite ores. In practice, flotation presents an effective method for the processing of such ores. However, it is not sufficient to produce a concentrate product with high Al2O3 grade from the ores with a single flotation process, especially from these containing abundant carbonate minerals. In this investigation, hydrochloric acid leaching was used to remove dolomite impurity from the flotation concentrate of a bauxite ore, to improve its Al2O3 grade and Al2O3/SiO2 (A/S) ratio. Effects of three dominant parameters on the leaching performance, that is leaching time, leaching temperature and hydrochloric acid concentration, were investigated in details. When these parameters were optimized, the aluminum concentrate assaying 67.41% Al2O3 with 66.84% recovery and 7.44 A/S ratio was obtained from the bauxite ore assaying 42.94% Al2O3 with 2.48 A/S ratio. It was concluded that hydrochloric acid leaching proved an effective method for upgrading of flotation concentrate from a low-grade bauxite ore containing carbonate minerals.

2

The flow line evolution of hot open ACDR process for titanium alloy discs

Zheng Y., Liu D., Zhang Z., Yang Y., Ren L.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 4

827--838

EN

Compared with traditional forging of titanium discs, the particular advantage for ACDR (axial closed die rolling) process is saving forming loading, but the weighted coefficient of compression and torsion happened on ACDR process show ambiguous even at the same axial forging ratio. Summed up from previous research, plastic yield process at ACDR forming is not only affected by the main stress caused from axial deformation, but also affected by shear stress from circumferential deformation. Flow line evolution as one of the manifestations, especially the circumferential deformation, should be studied to as basic theory to predict metal flow order, furthermore to define the deformation extent during ACDR process. Thus, this article presents flow line evolution laws with the three directions under different process conditions, emphasizing the difference of flow line evolution at different processing and the influence of process parameters associated with circles number n with the each direction. To achieve this purpose, numerical simulation with the essential boundary condition has been built. By means of systematic studying and discussing among deformation modes (stamping/machining, forging, high-pressure torsion, ACDR forming) and the process parameters (n, η, v, ω), the evolution law of flow line during hot ACDR on titanium alloy discs is achieved.

3

Modeling and Parameter Identification for Rubber Bearings under Random Excitation

Zheng Y., Jing H., Fang M., Xu X.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

75-78

EN

Based on the dynamic property test of rubber bearings a mathematical model of which is established under the condition of random excitation. The mathematical model shows that under random excitation the hysteretic restoring force is not only relevant to the displacement and the speed but also relevant to the mean value and the standard deviation of the random displacement. With the model the “force – displacement ”and “force –time” relationship under different sampling segments and working conditions is reconstructed and matches well with test results.

PL

Przeprowadzono testy właściwości dynamicznych łożyskowania gumowego przy przypadkowym charakterze pobudzeń. Opracowano model matematyczny pokazujący że nie tylko właściwości histerezowe wpływają na przesunięcia ale ważne są też wartość średnia i rozkład przesunięć.

4

An Optimal Kinematics Calculation Method for a Multi-DOF Manipulator

Zheng Y., Liu J., Kan J.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 7b

320--323

EN

Because of the complexity and time-consumption kinematics calculation, it is difficult to get solutions that can meet the requirements of kinematics calculation and real-time motion control simultaneously for the multi-degree of freedom (DOF) manipulator by a single processor. Based on the coordinate rotation digital computer (CORDIC) algorithm, the high-speed inverse kinematics calculation for a six-DOF manipulator is implemented in a co-processor and the motion control strategy is implemented in a host-processor. A pipelined architecture is adopted to reduce the time-consumption of the inverse kinematics calculation. The architecture of the parallel processing method is presented particularly. The experiment shows that time-consumption of the kinematics calculation is greatly reduced and the calculation results meet the requirement on the control accuracy.

PL

Bazując na algorytmie CORDIC (coordinate rotation digital computer) zaproponowano metodę obliczania kinematyki manipulatora o sześciu stopniach swobody. Zastosowano architekturę potokową i równoległe przetwarzanie danych. Osiągnięto znaczące skrócenie czasu obliczeń.

5

Study on new float polishing with the MCF

Shimada K., Matsuo Y., Yamamoto K., Zheng Y.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 23, nr 2

91-94

EN

Purpose: As a continuation of a previous paper, the report demonstrates the various possibilities of float polishing utilizing the present improved magnetic compound fluid (MCF). The MCF developed by one authors, Shimada, in 2001, was improved by the addition of alpha-cellulose, thereby achieving a clearance as great as 8 mm as shown in another paper. The present paper describes the possibility of the application of the MCF float polishing technique with alpha-cellulose. Design/methodology/approach: First, the results obtained under various polishing conditions of the MCF float polishing technique are described. These conditions include the various shapes of the magnet employed in the polishing tool, magnetic field strength, the concentration of alpha-cellulose, the motion of the specimen, the existence of a magnet fixed underneath the polished specimen, and initial surface roughness. Secondly, the present MCF float polishing technique can be used in many types of polishing, including polishing the inner surface of an acrylic resin tube, a wide flat surface through the use of a orbital polishing tool, and simultaneous float polishing of all surfaces of a three-dimensional complex shape. In addition, as other examples, the polishing on the integrated circuit (IC) substrate is shown. Findings: By the various polishing conditions of the MCF float polishing technique, the polishing effect is changed. On the other hand, as for the many applications of the MCF float polishing, inner surface, wide flat surface, rough initial surface, three-dimensional complex shape and IC substrate can be polished. Research limitations/implications: The data under various polishing conditions of the MCF float polishing technique helps to clarify the present polishing technique's possible practical applications. As shown in a previous paper, since MCF contains long magnetic clusters, the present polishing technique allows float polishing with large clearance. Therefore, many applications of the MCF float polishing are useful in the polishing fields. Practical implications: The present study indicates the practical application in the polishing. Originality/value: The present technique of MCF float polishing is new in the field of float polishing. In addition, the ordinary float polishing technique having large clearance has not been proposed. Therefore, the present paper is very useful in the polishing field.

6

Privacy Preserving Database Generation for Database Application Testing

Wu X., Wang Y., Guo S., Zheng Y.

Fundamenta Informaticae

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2007

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Vol. 78, nr 4

595-612

EN

Testing of database applications is of great importance. Although various studies have been conducted to investigate testing techniques for database design, relatively few efforts have been made to explicitly address the testing of database applications which requires a large amount of representative data available. As testing over live production databases is often infeasible in many situations due to the high risks of disclosure of confidential information or incorrect updating of real data, in this paper we investigate the problem of generating synthetic databases based on a-priori knowledge about production databases. Our approach is to fit the general location model using various characteristics (e.g., constraints, statistics, rules) extracted from a production database and then generate synthetic data using model learned. The generated data is valid and similar to real data in terms of statistical distribution, hence it can be used for functional and performance testing. As characteristics extracted may contain information which may be used by attackers to derive some confidential information about individuals, we present our disclosure analysis method which applies cell suppression technique for identity disclosure and perturbation for value disclosure analysis.