Complete magnetic separation technology for intermediate gangue qualified media of power coal prone to argillization

Abstract

The invention provides a complete magnetic separation technology for intermediate gangue qualified media of power coal prone to argillization. The technology includes the following steps that a middling coal and gangue suspension liquid subjected to dense medium separation is subjected to medium removal screening to form oversize materials, qualified media and dilute media; the qualified media andthe dilute media are merged and enter an intermediate gangue magnetic tail barrel; the intermediate gangue magnetic tailing barrel is fed into a strong magnetic disc type magnetic separator for roughing and is divided into concentrates and tailings; the magnetic separation tailings enter a coal slime bucket, and the magnetic separation concentrates enter a drum-type magnetic separator for concentration and are divided into concentrates and tailings; the magnetic separation concentrates return to a qualified medium barrel, and the magnetic separation tailings are divided into underflow and overflow through a grading cyclone; the underflow of the grading hydrocyclone is fed into coarse slime separation equipment or is doped with a gangue product, and the overflow of the grading hydrocycloneenters a thickener. According to the technology, high-ash fine silt in the intermediate gangue qualified media is completely discharged through two times of magnetic separation, the situations that repeated circulation of the high-ash fine silt intensifies gangue argillization and deteriorates the medium recovery and slime water treatment effects are avoided, and an effective means is provided for sufficient medium recovery and slime water treatment pressure reduction.

Description

technical field [0001] The invention belongs to the field of dense-medium coal preparation, and relates to a medium recovery process in the dense-medium coal preparation process, in particular to a magnetic separation process for gangue and medium in easily muddy steam coal. Background technique [0002] Dense medium coal preparation technology is the preferred method for coal preparation plants to process raw coal. However, for coal preparation plants with high clay mineral content in steam coal or raw coal, secondary slime is likely to be generated during the dense medium separation process, which has adverse effects on medium recovery and slime water treatment. [0003] The medium circulation link in dense medium coal preparation is the main cause of secondary slime. Research literature shows that the use of pressure-feeding two-product dense medium cyclone greatly increases the amount of secondary slime, and the amount of secondary slime increases. 7%. Secondary coal s...

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Problems solved by technology

[0006] Aiming at the problem that the high-ash fine mud mainly circulates in the medium qualified medium and cannot be discharged in time, which deteriorates the effect of slime water treatment and medium recovery, the present invention proposes that the medium qualified medium and the dilute medium are fully mixed and then jointly enter the magnetic separation-grading separation process. The process of removing high ash and fine mud in the qualified medium of gangue provides a process of full magnetic separation of gangue and medium in easily muddy steam coal

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