1 Structural characteristics and working principle of the moving sieve jig

1.1 Structural features

The moving sieve jig is mainly composed of a lifting wheel, a driving device, a tank body, a sieve plate, a drainage wheel, and a discharge chute. According to the different driving devices, the moving sieve jig is divided into two types: hydraulic drive type and mechanical drive type.

1.2 Working principle

After the material enters the moving sieve jig tank, the material and the sieve plate move up and down in the water under the driving of the driving device. During the movement, when the driving device drives up, there is no relative movement between the material and the sieve plate, and the aqueous medium moves downward relative to the material; when the driving device drives the sieve plate to descend, the material particles are affected by gravity and water medium. When the resistance is generated and the acceleration generated is less than the acceleration of the falling of the sieve plate, the aqueous medium forms an upward flow with respect to the sieve plate, and the bed can be suspended. When the falling speed of the particles is lower than the falling speed of the moving sieve, the material is disturbed and settled in the water, and the bed has sufficient looseness and loose time to realize effective layering of the materials according to the density. The stratified light and heavy products enter the double-pass lifting wheel respectively, relying on the double-channel lifting wheel to remove moisture, and the separated coal and vermiculite are sent into their respective discharge chutes. The permeable fines are discharged from the bottom tank discharge opening.

2 Application of moving sieve jig

2.1 Advantages of block coal moving screen drainage

The method of moving screens and draining is a process commonly used in the design of domestic coal preparation plants in recent years. It can be used for pre-processing of block raw coal, raw coal drainage, clean coal from block raw coal, separation of thermal coal, and treatment of dirty coal. Screening has the following advantages: the system is simpler and more automated. The sorting accuracy and quantity efficiency are similar to those of the heavy medium drainage process. The washing water itself circulates and only needs to replenish the amount of water taken away by the product. The process is simple, the investment is saved, and the operation and maintenance costs are low.

2.2 Application of moving sieve jig

The moving sieve jig has been used since the 16th century. In 1985, KHD of Germany developed a hydraulically driven ROMJI G moving sieve jig. The first prototype was used at the Emir-Meris Mine Coal Preparation Plant. In 1995, the Fushun Tiger Taiwan Coal Preparation Plant introduced the ROMJIG10.500.800 hydraulic moving sieve jig, which has a good effect.

In 1989, China's first hydraulically driven dynamic sieve jig prototype TD14/2.5 was industrially tested at Beipiao Guanshan Coal Preparation Plant. After that, the improved product TD14/2.8 hydraulic moving sieve jig was used in Fushun Longfeng Coal Preparation Plant to replace manual picking, and was certified and officially put into operation in 1993. In 1995, the TD14/3.2 hydraulic moving sieve jig was used in the Yima Yuejin Coal Preparation Plant for alternative screening, and the effect was better. The technical indexes of domestic hydraulic moving sieve jig have reached the same level in the world, but the control system and hydraulic system are not as reliable as the ROMJIG type moving sieve jig.

China's first mechanically driven prototype of the moving sieve jig GDT14/2.5 was used in the Badaoyu Coal Preparation Plant of Fuxin Mining Bureau to replace the screening. It was certified at the end of 1995. This type of mechanically driven moving sieve jig is simple in structure, reliable in operation and easy to maintain, and is popular on the spot. However, the machine is large in size and has a lower processing capacity than a hydraulic moving sieve jig.

In order to improve the level of coal preparation machinery and equipment in China, the former Ministry of Coal Industry decided to “use some of the third batch of energy loans to import some foreign equipment, introduce advanced technology through anti-contracting and cooperative manufacturing, and improve the ability and technology of China's coal preparation equipment manufacturing and equipment. "Level", to determine the introduction of the entire manufacturing technology of the German KHD company ROMJIG hydraulic moving sieve jig. The first prototype of foreign technology, domestic processing and manufacturing, hydraulic and electronic control, ROMJIG20.500.800 was put into operation in 1999 in Xinglongzhuang Coal Preparation Plant of Yankuang Group. Instead of roller crushing, it can directly produce clean coal or crush. It is sold as high-quality thermal coal (A ≤ 12%) or selected as a main selection system. The system passed the relevant appraisal in 2000.

2.3 Process effects of various moving sieve jigs

Each factory uses a moving sieve jig to treat lump coal with high strontium content. The ash content is high, the feeding range is 25-300mm, the processing capacity per unit area is 28-70t/h, and the I value is below 0.1. The quantity efficiency is basically above 95. In the Xinglongzhuang Mine (including the Yanzhou Mining Area and the Jibei Mining Area), low-ash and high-quality coal was obtained. At the same time, the water consumption of the moving sieve jig was extremely low, only 0.026-0.08 m3/h·t. There is no significant difference between the mechanical drive and the hydraulically driven moving sieve jig. The sorting efficiency is close to that of heavy media.

2.4 Reliability of the operation of the moving sieve jig From the use situation, the introduction of equipment work is relatively reliable, while the domestic equipment failure is relatively large, mainly due to the poor quality of hydraulic components.

The mechanically driven moving sieve jig is simple in structure and easy to operate and maintain. The reliability of operation is higher than that of the domestic hydraulic moving sieve jig, but the adjustment of its operating parameters is not as convenient and flexible as the hydraulic moving screen.

2.5 Investment sieve jig investment and economic benefits

The price of domestically produced mechanical sieve jig is the lowest, about 450,000 yuan/set, and the price of domestic hydraulic sieve jig is about 1 times that of the former. The price of imported equipment from Tigertai Coal Preparation Plant is the highest, nearly 10 times that of domestic equipment. The Xinglongzhuang model only has 40% of imported equipment, and the price performance is relatively high.

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