摘要:

Potential production methods for the production of low ash coal were investigated using a variety of Australian coal samples including natural fines, washed coal and washery rejects. Many samples could produce coal of less than 3% ash at yields exceeding 70% but the costs of comminution, beneficiation and dewatering for potential markets exceeded the value placed upon the low ash product.

ISSN:0734-9343    

DOI:10.1080/07349349308905105

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

One of the major problems facing further improvement in coarse coal flotation recovery has been identified as a need to increase the yield of coarse middlings material within the nominal minus 0.5 mm feed. To this end the chemical variables associated with coarse coal flotation have been investigated in detail. Increases in yield of up to 25% were obtained with a series of non-ionic frothers (relative to MIBC). These frothers produce very stable hydrated froths which are able to retain the middlings material, thus reducing the loss of floated coal from the froth. Non-ionic emulsifiers, such as nonyl phenol ethoxylates, were also found to increase coarse coal recovery by lowering the oil/water interfacial tension of the collector. However, excess emulsifier led to reduced flotation yields through a reduction in the three phase contact angle.

ISSN:0734-9343    

DOI:10.1080/07349349308905106

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A description is given of recent developments in flotation control strategy at Peak Downs Mine based on the ASHSCAN’coal gauge. Additional testwork undertaken to enhance this control strategy is detailed.

ISSN:0734-9343    

DOI:10.1080/07349349308905107

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An on-stream coal slurry analyser for both ash and % solids has been developed cooperatively by the Julius Kruttschnitt Mineral Research Centre and the Utah Development Company Limited. An industrial prototype of this unit has been operating successfully at the Peak Downs coal preparation plant since April, 1984 and has been used for automatic control of a bank of coarse flotation cells since January, 1985.

ISSN:0734-9343    

DOI:10.1080/07349349308905108

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Classical theories of filtration, based on the flow of fluids through packed beds of solids, may be confidently applied to ideal systems. However, these same equations may not be directly applicable in operating practice. Thus, it is usually necessary to study the effects of filtration variables on filter performance by leaf and pilot scale experiments.

ISSN:0734-9343    

DOI:10.1080/07349349308905109

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A non-contacting microwave transmission gauge has been developed for on-conveyor determination of moisture in coal. A laboratory evaluation has been completed on a range of fine (< 5 mm) and coarse (< 50 mm) coal samples from New South Wales, coal washeries.

ISSN:0734-9343    

DOI:10.1080/07349349308905110

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

With lower moisture specifications becoming the norm on coal sales contracts, Curragh Queensland Mining Limited has found itself under increasing pressure to reduce product moisture levels out of its preparation plant. This paper reports the efforts by site staff to identify and implement methods of achieving the goal. It describes the results of surveys carried out to highlight which area would produce the greatest benefit from attention and explains why the fine coal product was chosen. Results of surveys and testwork designed to pinpoint the aspects of the operation of the screen bowl centrifuges used for dewatering this product which could be modified are shown. The implementation of these changes is discussed and the resultant moisture reduction shown.

ISSN:0734-9343    

DOI:10.1080/07349349308905111

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A mathematical model of the dense medium cyclone process has been developed by researchers at the JKMRC over a number of years. It has utilised empirical relationships between key performance criteria (such as cut point andEpfor the various size fractions) and cyclone geometry and operating parameters. This model is based on an extensive array of data collected from a large number of operating plants as well as pilot plant data. An alternative mechanistically derived model of dense medium cyclone performance based on balancing the terminal velocities of discrete particles due to the centrifugal force experienced in the cyclone against a random turbulent eddy velocity has also been developed from the separation model of Schubert and Neesse. This paper illustrates how the latter model has been integrated into the empirical but more comprehensive JKMRC model in an attempt to provide a more robust model capable of application to a wider range of cyclone operations. In addition, this allows and improved understanding of the key operating characteristics of dense medium cyclones.

ISSN:0734-9343    

DOI:10.1080/07349349308905112

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

A study of coal washing spiral operation and performance is under way at the JKMRC. The program has two components—a pilot plant study, and sampling programs conducted in operating washeries. The objective is to use the pilot plant data to develop a fundamental understanding of the spiral separation process, and to formulate a model of spiral performance which can be subsequently validated and extended by the incorporation of field data.

ISSN:0734-9343    

DOI:10.1080/07349349308905113

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The performance of three different types of spirals and a 200 mm diameter water washing cyclone have been assessed in open-circuit on-site testwork at the Norwich Park preparation plant on nominally 500 µ x 75 µm sized coal. The study is part of a program investigating alternative methods to heavy media cyclones and froth flotation for removing ash from fine coal from Central Queensland mines in the nominally 3 mm x 75 µm size range.

ISSN:0734-9343    

DOI:10.1080/07349349308905114

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor