1 Major problems before the implementation of technological transformation Due to the adoption of fully mechanized mining technology in mines and the frequent changes in coal seam structure, the amount of coal containing coal and the amount of primary coal mud increased significantly, which made the original coal screening crushing system, heavy medium sorting system and flotation system of Wangjiazhai Coal Preparation Plant. The coal slurry water treatment system has experienced a decline in production capacity to varying degrees. The production index is far below the year-on-year level, and the production efficiency has dropped significantly. Mainly in the following aspects: (1) Raw coal is directly blocked as sales of electric coal, which seriously restricts mine production. Due to the poor conditions of coal seams in Naluozhai Coal Mine, the raw coal ash is about 44.5%, and the sulfur content is up to 2.7%. It is difficult to meet the quality requirements of coal. However, if the raw coal is selected at the whole level, the yield of clean coal is low, the mudstone is seriously muddy, the production pressure of the slime water system is large, and the benefit is low. (2) The selection ability is low and cannot meet the normal production of the mine. The heavy medium main selection system uses two sets of 3GDMCl200/850 cyclones. The designed raw coal treatment capacity is 500t/h, and the actual average is about 380t/h. The reason is that the raw coal entering the plant has not been screened by hand, and the whole stage enters the crusher , and the upper limit of crushing particle size is difficult to control, the heavy medium cyclone is blocked frequently, and the production efficiency is low; the dewatering and recovery capacity of the slime is insufficient, which restricts the heavy medium sorting. The system is continuously and stably produced; the quality of raw coal is deteriorated and the slime is sticky, resulting in difficulty in discharging the warehouse and uneven feeding amount. (3) The effect of heavy medium selection and flotation is poor, and the actual production data deviates greatly from the theoretical data. Mainly in the consumption of up to 4.5kg / t, far higher than the same industry level; high circulating water concentration, in order to ensure mine production, forced coal washing production, resulting in heavy medium selection and flotation effect deterioration; heavy medium operation is difficult, not Stable, resulting in a density of less than 1.80kg / L in vermiculite of about 4%, and less than 1.40kg / L in washing coal is about 10%. (4) The recovery capacity of coal slurry is low, which seriously restricts the production of heavy medium coal. Mainly manifested in the aging of dewatering equipment , can not effectively recover flotation concentrate in time, thus restricting the normal production of flotation, and due to the high moisture of flotation clean coal, it has an adverse effect on the external sales; tail coal slurry can not be effectively recovered, resulting in circulating water concentration Increased, thus affecting the entire coal washing production. 2 technical transformation content and effect In response to the above problems, the Wangjiazhai Coal Preparation Plant has carried out technical transformation in stages in a batch and prioritized manner. 2.1 Naluozhai Mine Raw Coal Screening Treatment The quality of raw coal in Naluozhai Mine is shown in Table 1. Considering the quality of raw coal in the mine and the production cost, according to the principle of maximizing the benefit of washing and processing, the raw coal of the mine is more suitable for washing and processing according to thermal coal. The coal preparation plant determines that the screening process is adopted, and the low-ash high-heating materials under the sieve are directly sold as thermal coal products, and the high-ash low-calorie materials are screened into the heavy medium sorting system. A new classification system has been added to the original coal screening and crushing building. The production practice proves that the system runs stably, which ensures the production of inferior raw coal in the mine, and at the same time reduces the cost of washing and processing. 2.2 Realize closed cycle of washing water The Wangjiazhai Coal Preparation Plant has been in operation for a long time. Due to historical reasons, the plant area is mixed with the villagers' area, resulting in the complete separation of production and domestic water. The production water is extremely unbalanced. When the water volume is large, the load of the slime water concentrator is increased and the circulating water concentration is high. It is difficult to guarantee coal washing production. Based on this, the coal preparation plant decided to implement the clean water separation and washing water balance treatment project for the whole plant. Separation of sewage is mainly to collect and recycle the villagers' living water and the staff's bathhouse water in the plant area to ensure that the sewage is not discharged; reduce the amount of fresh water in the production system. The water-washing balance project mainly uses high-quality circulating water to replace the clean water consumed by the system, so that the amount of water entering the system is equal to the amount of water taken away by the product, achieving a wash water balance and a closed circuit cycle. Technical reform measures: Using the existing four smelting concentrators, three of them are used as tailings for concentration, one part of the overflow is used as the heavy medium de-spraying water, and the other part is treated again by another high-efficiency concentrator. As a water supply for the packing cooling and production system of the pump, it produces sanitary water for the post and cleans the road water for the plant. After the technical reform, the current situation of excessive water production in the production system was eliminated, and the quality of the circulating water was effectively controlled to facilitate the production of the heavy medium flotation system. 2.3 Management of the heavy media system (1) In view of the problem that the original coal bunk is easy to block and the amount of unloading is extremely unstable, air cannons are arranged on the four sides of the existing square silo bucket, and the instantaneous coal is used to break up the raw coal to achieve the purpose of smooth cutting of the raw coal. (2) Analysis of the main raw materials in the coal preparation plant in recent years is that the medium is easy to beat, the equipment of the recovery system is seriously aging, the material of the de-intercalation screen is uneven, and the residence time of the material on the de-screening is short. The effect of dissociation is poor. Mainly following measures: â‘ magnetic iron ore pre-wetted and then added with stirring to avoid lumping medium: â‘¡ increase sculping fixed on each sieve product chute after heavy medium cyclone separation, improve the ability to pre-sculping To reduce the load of the fixed arc screen; 3 update the four aging magnetic separators, and add a water spray device to ensure the effective recovery of the medium; 4 improve the fixed arc screen feeding mode to ensure uniform discharge of the off-cut screen; 5 pairs The de-screening section increases the water-blocking station, delays the residence time of the material on the screen surface, and strengthens the de-intermediation; 6 strengthens the inspection management of each medium recovery equipment. After the technical transformation, the dielectric consumption is maintained at about 3.0 kg/t (the magnetite content of the magnetite powder used in our factory is not less than 93%, the density is not less than 4.3kg/L, and the density of less than 325 mesh is not less than 80%) . (3) For the problem of high content of suspended coal slurry, the following technical measures are taken: under the premise of stable medium consumption, the flow rate is increased to ensure that the coal slurry content in the sorting suspension is about 55%; Stable diversion, wash volume and water spray. After the technical transformation, the heavy medium separation suspension was stabilized, and the loss of coal blended in the vermiculite was controlled below 2%, and the loss of clean coal in the washed coal was controlled below 6%. 2.4 Secondary screening of washed raw coal According to the actual situation of the production site, after analysis and demonstration, after the raw coal entering the plant is crushed, the ash content of the material larger than 60 mm is about 69.00%, and the content of less than 1.8 kg/L is only about 3%, accounting for 0.5% of the whole grade. Therefore, the technical reform considers the secondary screening of the materials in the raw coal transportation process. The sieved materials are discarded by the backhand selection and the fines are separated from the hand-selected lump coal into the heavy medium cyclone. The actual operation shows that after the system is reformed, the upper limit of the particle size of the heavy medium cyclone is controlled, which reduces the occurrence of cyclone blockage accidents and achieves continuous and stable production. 2 5 Improve the flotation process system The purpose of the technical transformation is to improve the processing capacity of the coal slurry water equipment, ensure the effective recovery of the slime in all links, and provide the necessary conditions for the benign operation of the circulating water. The main problems of the flotation recovery system are as follows: (1) The flotation agent is directly added, the dispersibility of the diesel oil in the slurry is poor, the oil molecule diameter is large, the probability of adhesion to the coal particles is low, the efficiency is low, and the fuel consumption is large. (2) Flotation clean coal is combined with dewatering and recovery by using a disc vacuum filter and a pressure filter. Due to frequent changes in coal quality, the use of equipment is deteriorated, the treatment capacity is reduced, the water content is high, and the flotation production is severely restricted. low quality. (3) Due to the fact that the chemical addition system and the previous mixed coagulation do not meet the dehydration requirements, the tail coal belt filter press has lower production capacity and higher product moisture. In response to these problems, the following modifications were taken: (1) The flotation agent is first emulsified and then sent to the flotation feed tank, premixed with the slurry in the feed pump, further mixed by the pipe mixer, and finally sorted by the flotation machine. Practice has proved that this method can greatly improve the flotation effect, shorten the flotation time, improve the concentrate yield, and increase the tailings ash by more than 5% on the premise of ensuring the quality of the concentrate. (2) Improve the processing capacity of flotation clean coal recovery equipment and reduce the moisture of clean coal. The sedimentation filter centrifugal dewatering machine and the clean coal filter press combined with dehydration technology replaced the original process. The flotation concentrate is dewatered after being cut into coarse sediments, and the product is used as the final clean coal. The filtrate is pumped into the clean coal filter press and dehydrated again. The filter cake is used as a clean coal product, and the filtrate is recycled as a flotation feed dilution water. After the transformation, the flotation system treatment capacity is increased by about 50%, and the flotation clean coal moisture is maintained at 21%. (3) Reconstruction of the auxiliary system of the belt filter press: 1 The agent is pre-stirred and then sent to the constant pressure dosing box, and then divided into the feed end of each belt filter press to replace the original single pump delivery system; 2 The slurry is transported by a single pump through a pipe mixer and mixed with the agent to the constant pressure feed box, and then distributed to the front-end two-stage pipe mixer of each equipment, replacing the original single pump feeding mode. After the transformation, the quality of the coal slurry of the belt filter press was effectively improved, and the single-machine processing capacity was improved by 1/3. 3 Technical transformation benefits (1) The coal preparation system is continuously stable, which ensures the continuous production of the mine. After the implementation of the transformation, the raw coal treatment capacity reached about 450 t / h. In the past two years, the raw coal treatment reached 2.4 million tons, the production time was shortened by 980 hours, the direct electricity cost was reduced by 250,000 yuan, and the indirect production cost was also greatly reduced. (2) Production indicators have improved significantly. The quality of the products was optimized, the loss of meteorites was reduced by 2%, the loss of washed coal was reduced by 4%, the comprehensive recovery rate was increased by 1%, the recovery rate of clean coal was increased by 1.5%, and the sales revenue was increased by about 36 million yuan. (3) After the technical recovery of the medium recovery system, the production consumption is reduced from 4.5 kg/t to 3.0 krdt, and the annual consumption of raw coal is 2.4 million tons, which can save 4.5 million yuan. After the implementation of the technical transformation, the direct economic benefits for the year increased by 40.75 million yuan. 4 Conclusion The Wangjiazhai Coal Preparation Plant has improved the production status of the coal preparation plant and adopted a series of coal washing process reform measures to improve the economic efficiency of the company. This case shows that only by continuously improving the scientific and technological content can we gain market dominance and use the new coal washing process to gain a certain market share in the coal washing market. 1. Portability: Pop-up counters are designed to be lightweight and easy to transport, making them ideal for trade shows, exhibitions, and other events. Pop Up Counter 2By1,Convenient Pop Up Display Stands,Light Pop Up Display,Pop Up Displays SUZHOU JH DISPLAY&EXHIBITION EQUIPMENT CO.,LTD , https://www.jh-displaystand.com
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Guizhou Shuicheng Mining (Group) Co., Ltd. Wangjiazai selected coal plant in September 1970 put into operation, the original design Coal Capacity 1.5Mt / a. After many technical transformations, in 2002, it was changed to the combined process of raw coal non-pressure feeding three-product heavy medium cyclone sorting and coal flotation flotation. The production capacity reached 2.4Mt/a, which was mainly selected in Wangjiazhai Coal Mine and that. Raw coal in Luozhai Coal Mine is made up of coking coal and washing coal, mainly for large enterprises such as steel mills, coking, chemicals and power generation.