Abstract:To address issues in the original coarse slime system's"spiral separator+sieve bend"process—such as coarse clean coal"carrying excessive ash"under normal coal quality,waste of high-quality resources during coal quality fluctuations,and low desliming efficiency—Wangpo Coal Preparation Plant optimized the process by implementing a new combination of"TBS+tri-mass electromagnetic vibrating screen+slime centrifuge."Through production tests and data analysis,the feasibility and superiority of the optimization scheme were veri-fied.Under normal coal quality(feed ash≤35%),the ash content of coarse clean coal dropped to 10.84%after separation and dehydration,meeting the blending requirements for clean coal without reducing the separation density of slack coal,thus avoiding yield loss of final clean coal.During abnormal coal quality periods(feed ash>35%),the ash content of coarse clean coal was optimized to 13.39%;a minor reduction of only 0.6 percentage points in final clean coal ash was sufficient to balance the"excessive ash"phenomenon,preventing high-quality resources from being mixed into raw slack coal.Post-renovation,the desliming efficiency of the tri-mass electro-magnetic screen increased to over 92%,significantly outperforming the original sieve bend.Calculations show that for an annual processing capacity of 3 million tons of raw coal,the optimization can increase the enterprise's economic benefits by 12.625 5 million yuan per year.This study provides a practical technical reference for op-timizing coarse slime systems in mine-type coal preparation plants with high coal quality fluctuations.

Abstract:This paper systematically carries out parameter optimization and structural innovation design for a 1.3 m horizontal scraper discharge centrifuge to achieve domestic substitution.The overall structure of the equipment and the mechanism of centrifugal dehydration are elucidated.With the objectives of"high processing capacity,low product moisture,and high reliability,"the study focuses on key parameters such as separation factor,screen basket structure,and differential speed.Through theoretical modeling and quantitative calculation,core operating parameters are determined,including a screen basket diameter of 1 300 mm,a separation factor of 302,and a motor power of 110 kW.The matching relationship between material residence time and screen bas-ket opening rate is optimized to ensure a balance between dehydration efficiency and processing capacity.Innov-ative designs are implemented,including a split-type frame,an inverted-cone screen basket and scraper arrange-ment,and targeted wear-resistant protection structures.These innovations solve technical hurdles such as diffi-cult maintenance of large-scale equipment,short service life of wear parts,and irrational bearing stress distribu-tion.Performance tests indicate that the unit processing capacity reaches 78 t/h,with product moisture con-trolled between 12%and 16%.Vibration,noise,and temperature rise all meet design standards,with compre-hensive performance reaching the level of similar international products.The successful development of this equipment breaks the reliance on imports,provides technical support for the selection of coarse slime dehydra-tion equipment in large-scale coal preparation plants,and is of great significance in promoting the large-scale and localized development of coal preparation equipment.

Abstract:Addressing the challenges of difficult sedimentation and high difficulty in high-ash fine coal slime water,along with the inherent drawbacks of traditional dosing modes,the Sihe No.2 Mine Coal Preparation Plant implemented a systematic,full-process transformation of its dosing system.Reagent parameters were op-timized through experimental analysis,and several key components were independently developed,including an anti-interruption and leakage alarm device,a non-powered spiral mixing device,and a mechanical stirring device.By deploying intelligent monitoring instruments such as concentration meters,slime interface meters,and conductivity meters,the plant optimized its control logic to achieve an intelligent upgrade across reagent preparation,dosing,and mixing.The results indicate that the treatment efficiency of coal slime water improved significantly post-transformation,while reagent consumption and equipment costs were substantially reduced.Specifically,the thickening efficiency increased from 90.89%to 93.65%,the underflow solid yield rose from 97.66%to 98.90%,and the pressure filtration cycle was shortened from 2 400 s to 2 100 s.The dosage of poly-aluminum chloride(PAC)and polyacrylamide(PAM)decreased to 4.81 kg/t(a 12.55%reduction)and 0.38 kg/t(a 20.83%reduction),respectively.Furthermore,the consumption of slurry pumps was reduced by 7 units per year,saving approximately 660 000 yuan annually.This transformation achieves precise reagent dos-ing and high-efficiency mixing,demonstrating significant technical innovation and engineering practicality,which provides a valuable reference for the treatment of similar difficult-to-settle coal slime water.

Abstract:In response to issues such as suboptimal separation efficiency and insufficient equipment capacity in the dense medium separation system,arising from the implementation of the online switching process between raw coal desliming and non-desliming feed,the Xin'an Coal Industry Co.Ltd.Coal Preparation Plant upgraded the original traditional-structure pressure-free feeding three-product dense medium cyclone to a dual-cone struc-ture.Additionally,the plant replaced the accompanying reject medium drainage screen and improved the trans-portation capacity of the tubular belt conveyor for reject,achieving collaborative optimization of the system.Following the optimization,the dense medium separation performance improved significantly:the probable de-viation of the primary cyclone decreased to 0.03 g/cm3,and that of the secondary cyclone reached 0.045 g/cm3;the coal loss in middlings dropped from 20%to 1.32%,and the coal loss in gangue approached zero.The raw coal processing capacity increased by 50 t/h,and the clean coal yield rose by 1.39 percentage points.Meanwhile,media consumption per ton of coal was reduced by 0.15 kg,and power consumption per ton decreased by 0.56 kW·h,resulting in an estimated annual economic benefit of approximately 6.855 4 million yuan.This op-timization practice can provide valuable insights for coal preparation plants with similar production conditions in optimizing their separation processes.

Abstract:To address the issues of low resource utilization and untapped economic potential of heavy-medium middlings,and to implement the principle of"maximizing coal resource extraction,"the Luliangshan Coal Pre-paration Plant compared microwave heating and liquid nitrogen condensation to determine the optimal pretreat-ment scheme,and conducted a feasibility study on the crushing,liberation,and re-separation of middlings.Us-ing a combined methodology of pretreatment,crushing,screening,float-and-sink tests,X-ray diffraction(XRD),and scanning electron microscopy(SEM).The results indicate that liquid nitrogen condensation pretreatment is more conducive to density separation in subsequent float-and-sink tests.When middlings with a particle size of>6 mm are crushed to below 6 mm for re-separation,the plant can increase clean coal production by 7 500 tons per year,while maintaining middling production at 187 800 tons.The average annual profit increase is estimated at 2.598 9 million yuan.At this particle size,the dominant density fraction is 1.6～1.8 g/cm3(yield of 47.24%),while the low-density fraction of<1.4 g/cm3 reaches a yield of 7.73%with an ash content of 11.95%.The liber-ation effect between clean coal and reject is significantly superior to the>13 mm crushing scheme.The de-signed 6 mm crushing and re-separation process for coking middlings effectively improves resource recovery,offering substantial economic benefits and resource utilization value.

Abstract:To overcome the bottlenecks of high labor intensity,high operating costs,and low intelligence levels in the manual separating process of the raw coal refuse discharging system,Jiangzhuang Coal Mine implemen-ted a full-process intelligent reconstruction of its"shallow-depth heavy medium bath&manual reverse separat-ing"process(in operation since 2014).This was achieved through the coupling and integration of control tech-nologies:"50～200 mm intelligent dry separating,>200 mm LIDAR separating,and>50 mm total refuse crush-ing."The study utilizes a three-stage roller screen classification as the starting point.Raw coal blocks of 50～200 mm are directed into an X-ray&vision dual-mode intelligent dry separating system,while blocks>200 mm are identified by 3D LIDAR and diverted at high speed via guide plates.All refuse>50 mm is reduced to<80 mm by a double-toothed roll crusher and transported via an enclosed pipe belt conveyor.Simultaneously,a centralized control platform was embedded to integrate data from seven stages—feeding,screening,crushing,separating,transportation,dust extraction,and video monitoring—into the dispatch center,enabling"one-click start-stop,remote linkage,and fault self-diagnosis."Production practice demonstrates that the labor efficiency of the raw coal system surged from 320.51 t/shift to 757.57 t/shift,with an annual cost saving of 4.170 6 million RMB.Manual separating and mine-car refuse discharge have been eliminated,resulting in zero minor injuries or major accidents for two consecutive years.The system features wet-dry compatibility,allowing a switch to the backup shallow-depth system within 5 minutes to ensure continuous production.This practice establishes an in-tegrated"classification-identification-crushing-centralized control"refuse discharging process.It constructs a demonstration model for aging mines in their resource-depletion stage to reduce manpower through technology,ensure safety via intelligence,and cut costs through intensification,providing a replicable and scalable low-cost intelligent upgrade path for similar coking coal preparation plants.

Abstract:To promote the transformation of coal preparation plants from fragmented intelligence to full-process collaborative intelligence,and to support the high-quality development of the coal industry alongside the clean and efficient utilization of energy,this paper systematically explores the practical significance and construction paths of the"Lights-out"coal preparation plant as an advanced stage of intelligent coal preparation.Based on a review of the current status of intelligent construction in China's coal preparation plants,the study identifies core challenges,including immature key technologies,insufficient depth of intelligence,misalignment between man-agement systems and intelligent requirements,high investment pressure with poor operational sustainability,and an incomplete standard system that hinders replication and promotion.The paper proposes a phased,progressive,and pragmatic approach across three dimensions:space,business,and technology.It outlines a three-level gradi-ent path—"Single Link—Multi-system—Plant-wide Intelligentization"(L1—L2—L3)—to advance construc-tion.Furthermore,targeted countermeasures and suggestions are provided from four perspectives:technical breakthroughs and standardization,policy guidance and incentive mechanisms,management model innovation and talent cultivation,and demonstration leadership and classified promotion.This study aims to foster a replic-able and scalable construction model for"Lights-out"coal preparation plants,providing theoretical support and practical references for achieving unmanned full-process operations,self-adaptive optimization,and intrinsic safety in coal preparation.

Abstract:In coal preparation practice,when the slime content of raw coal is high,pre-desliming is typically in-corporated into the process design to prevent excessive slime from negatively impacting separation efficiency.To simplify the processing circuit and explore the feasibility of non-desliming separation for high-slime raw coal,this paper presents a quantitative calculation of slime content in the separation medium.Taking the Xieji-ahegou Coal Preparation Plant in Guizhou as a case study,it introduces the practical application of a combined circuit:primary separation with non-desliming pressureless-fed three-product heavy medium cyclones(HMC)+coarse slime separation with coal slime HMC+fine slime flotation.Operational results demonstrate that:the primary three-product HMC obtained satisfactory separation results,such as,the average gangue loss in clean coal is 0.29%,the average coal loss in middling coal is 0.84%,the average coal loss in gangue is 0.08%,and maintained an average throughput of 420～450 t/h,reaching a maximum of 520 t/h.Production statistics from January to September 2024 show that despite a primary slime content of approximately 25%(and a total slime content of roughly 40%including secondary slime),the plant maintained a magnetite consumption of less than 1.0 kg/t and power consumption of 6.0 kW·h/t.The successful implementation of the non-desliming process for high-slime raw coal at Xiejiahegou Coal Preparation Plant indicates that,through rational process design,proper equipment selection,optimization of the medium recovery circuit,and the implementation of effective management measures,the non-desliming process achieved high efficiency and low consumption.

Abstract:Existing cleaning devices for pressure filters face issues such as downtime cleaning affecting produc-tion continuity,periodic cleaning increasing cleaning difficulty,and low efficiency of water resource recycling.To address these problems,a negative pressure cleaning system for filter cloth,consisting of a cleaner,a wash-water separation chamber,and a wash-water circulation device,is proposed.This system utilizes the principle of negative pressure drive to achieve reverse dynamic cleaning of the filter cloth.By leveraging the solid-liquid separation function of the wash-water separation chamber and the secondary filtration of the circulation device,a closed-loop circuit of"cleaning—separation—filtration—reuse"is constructed.The results show that the sys-tem achieves simultaneous operation of filtration and cloth cleaning,which significantly improves the continu-ous operation time and filtration efficiency of the pressure filter.It removes residual coal slime on the cloth sur-face in real time,extending the service life of the filter cloth.Furthermore,it reduces the water cost of the coal preparation plant,with fresh water consumption expected to decrease by more than 30%.The negative pressure cleaning system for pressure filter cloth breaks through the limitations of traditional cleaning,achieves real-time cleaning and closed-loop recycling of wash water,effectively solves the key pain points of traditional cleaning technology,and meets the green and low-carbon development requirements of the coal preparation industry.

Abstract:To address the issues of severe clogging,frequent cleaning,and high energy consumption in the ori-ginal crushing system caused by the high viscosity and high moisture characteristics of coal slime filter cake in wet coal preparation processes,Luling Mine replaced the original hammer crusher with a roller-type coal slime crusher for optimization and upgrading.The equipment is based on the core principle of shear crushing,con-figured with a staggered arrangement of curved pear-shaped blades and three sets of independently driven roller systems.Through the collaborative design of the first two rollers rotating in the same direction and the third roller rotating in reverse,it establishes a graduated crushing process and achieves screenless,adjustable-gap crushing.Production practice demonstrates that the upgraded equipment possesses strong processing capacity and produces a uniform discharge size that meets the<50 mm requirement,with no clogging or sticking observed within the machine housing.Compared to the original equipment,its unit energy consumption is reduced by 85%,the lifespan of wear parts is extended by 3.3 times,and the cleaning frequency is reduced from once daily to once monthly,significantly lowering operating costs and labor intensity.This optimization effectively re-solves technical challenges in crushing high-viscosity wet coal slime,provides reliable technical equipment sup-port for the resource utilization of coal slime in preparation plants,and offers general applicability for the crush-ing of similar viscous and wet materials.

Abstract:Against the backdrop of the deepening"Dual Carbon"strategy and the accelerated transformation of the energy structure,China's coal industry is undergoing a profound shift,extending from its primary role as a fuel towards increased utilization as a raw material and feedstock.As the crucial first step in the clean and effi-cient utilization of coal,coal preparation holds growing strategic importance.Based on the policydirection fol-lowing the implementation of the Energy Law of the People's Republic of China in 2025,and considering the ex-plosive growth of new energy industries and the technological upgrades in coal-consuming sectors(such as coal-fired power,metallurgy,and coal chemicals),this study systematically investigates the development path for the coal preparation industry.It addresses existing challenges,including fluctuations in the raw coal washing rate,fragmented intelligent construction,and insufficient alignment of process selection with market demands.The analysis synthesizes the resource distribution characteristics of Shanxi,Shaanxi,Inner Mongolia,and Xinjiang,which account for over 82%of national output,and the application status of leading technologies like dry coal separation and dense medium separation.It underscores that the industry must closely align with the core re-quirement of low-carbon development.At the process design level,it proposes prioritizing dry separation for steam coal and coal for chemical use,and promoting a"dry coarse separation+wet fine separation"model for metallurgical coal,while strengthening integrated mine-preparation-backfill design and coupled applications with new energy.In terms of the management system,it suggests establishing specialized coal quality and pre-paration centers to promote deeper integration of mining and preparation,alongside enhanced IT-based manage-ment and control.From a production and operation perspective,it recommends building a market-oriented,cus-tomized product system and value-added utilization chains for by-products.In the realm of technological innova-tion,the focus should be on developing large-scale equipment,intelligent decision-making systems,and separa-tion technologies for specific coal types.Furthermore,from a policy support standpoint,proposals include estab-lishing a full-chain coal quality management system,differentiated fiscal and tax incentive mechanisms,and in-terdisciplinary talent cultivation models.The study aims to promote a multi-dimensional coordinated optimiza-tion,driving the coal preparation industry towards low-carbon processes,professional management,high-value products,and intelligent efficiency.This provides a practical pathway for improving coal resource utilization ef-ficiency and reducing carbon emissions across the entire industrial chain,thereby supporting the synergistic achievement of China's"Dual Carbon"goals and energy security strategy.

Abstract:To address the issues of high lag,low accuracy,and significant errors in moisture detection of filter cake during the filter press dewatering process,a soft measurement method for filter cake moisture based on Regularized Stochastic Configuration(RSC)is proposed:seven key operational parameters,including feed con-centration,feed flow rate,and feed pressure,are selected as input variables,with filter cake moisture as the out-put variable,to construct a data-driven nonlinear regression model.Using 200 sets of industrial field data as samples,the dataset is divided into training and testing sets in a 7∶3 ratio.The model's effectiveness is valid-ated by comparing its performance with linear models(Linear)and Stochastic Configuration Networks(SCN),incorporating evaluation metrics such as Mean Absolute Error(MAE),Root Mean Square Error(RMSE),and the coefficient of determination(R2),along with error characteristic analysis.The results show that the RSC model significantly outperforms the comparative models,with MAE and RMSE as low as 0.45 and 0.56,respectively,and an R2 of 97.65%.In terms of relative error,the RSC model achieves sample proportions of 65.63%for er-rors less than 1.0%and 96.88%for errors less than 2.0%.The model exhibits good independence and non-sys-tematic characteristics in prediction errors,with autocorrelation coefficients for all lag orders except lag 0 fall-ing within the confidence interval.By providing real-time predictions of filter cake moisture,this method en-ables flexible adjustment of the filter press's feed pressure,pressing pressure,and holding time,further improv-ing dewatering efficiency,reducing energy consumption,and enhancing the continuity and stability of the pro-duction process.

Abstract:Addressing the technical deficiencies in the current standard GB/T 26919-2011 Coal Preparation Plant—Experimental Method for Natural Sedimentation of Coal Slurry,the authors propose systematic revision suggestions based on practical application,experimental comparison,and data validation.These suggestions cover four key areas:improvement of experimental apparatus,optimization of measurement methods,simplifica-tion of curve plotting,and standardization of graphic and textual descriptions.Specifically,it is recommended to install a scale on the sedimentation column for easier liquid level readings and a rubber buffer pad at the bottom of the stirrer to prevent equipment damage.For the determination of dissolved solids content,a sedimentation time of 1 h and a 0.45 μm filter membrane are proposed,alongside the use of a water bath for drying to simplify the workflow.It is further suggested to use logarithmic coordinates for plotting natural sedimentation velocity distribution curves,enabling a single graph to clearly present details across a wide range of velocities.Addition-ally,errors in sampling volume within the standard's examples are corrected,and non-standard graphic/textual expressions are addressed.These recommendations provide a technical basis for the revision of GB/T 26919-2011 Coal Preparation Plant—Experimental Method for Natural Sedimentation of Coal Slurry,enhan-cing the standard's scientific rigor,accuracy,and practicality.This work offers more efficient and reliable tech-nical support for coal slurry sedimentation testing and the design and operation of coal slurry treatment systems.

Abstract:The stirring and dissolution of flocculants are critical steps in the coal slurry water treatment process at coal preparation plants.To address the challenges of accurately controlling the dissolution quality and uni-formity of flocculants,the lack of viscosity detection technology that balances effectiveness and real-time capab-ility,and the insufficient research on flocculant dissolution and stirring equipment,an automatic flocculant dos-ing system based on the stirring and dissolution principles of anionic polyacrylamide(APAM)is proposed.The system consists of three parts:quantitative dosing and conveying,pneumatic dispersion,and viscosity detection and stirring,with intelligent control achieved through a PLC and an upper computer.Based on the mechanical stirring power formula and Nagata Sadaharu's power number,the mathematical relationship between stirring power and the kinematic viscosity of APAM solution is derived.Experimental methods are used to investigate the dissolution patterns of APAM with different molecular weights(4 million,8 million,12 million,16 million,18 million,and 20 million)at stirring speeds ranging from 200 to 1 000 rpm.A mathematical model linking kin-ematic viscosity and stirring power is established,and the effectiveness of the system and model is verified through simulated field tests.The results show that the kinematic viscosity of the APAM solution initially in-creases and then decreases with increasing stirring power,with an optimal stirring power corresponding to the maximum kinematic viscosity.Based on the derived mathematical model,the average relative error between the kinematic viscosity calculated from stirring power and the actual measured values is less than 6%.The designed automatic dosing system enables non-contact,real-time detection of the kinematic viscosity of APAM solution,operates stably,is easy to use,and effectively controls the viscosity of the flocculant solution.This system and the derived mathematical model address the precision issues of traditional dosing methods,enhance the intelli-gence and reliability of flocculant addition in coal slurry water treatment,and provide theoretical guidance for optimizing flocculant dissolution parameters.

Abstract:In order to address issues such as reliance on manual experience in density control of the heavy medi-um separation system,aging detection equipment,and delayed parameter feedback,the Handan Coal Prepara-tion Plant has implemented an intelligent upgrade of its heavy medium separation system.A three-layer architec-ture intelligent control system for heavy medium separation—comprising the equipment layer,control layer,and management layer—was established.New equipment,including density meters and magnetic content analyzers,was deployed,and an intelligent regulation model for suspension density was developed,enabling dual-mode manual and automatic control.After the system was put into operation,clean coal in middlings reduced by 0.5 percentage points,coal in refuse reduced by 1.6 percentage points,medium consumption decreased by 0.15 kg/t,and the fluctuation of suspension density was controlled within±0.005 g/cm3.The system realizes intelligent setting and regulation of suspension density,completing the transformation from automation to intelligence.This lays a solid foundation for further enhancing the overall intelligence level of the plant.

Abstract:In order to solve the problem of large amount and poor dispersibility of traditional collectors such as kerosene and diesel in the process of coal slime flotation,the diesel micro-emulsion collector was prepared us-ing cetyl trimethyl ammonium bromide(CTAB),n-amyl alcohol or n-butanol,diesel oil and water as raw materi-als.CTAB was combined with n-amyl alcohol or n-butanol to form a complex emulsifier.The pseudo-ternary phase diagram showed that n-amyl alcohol was the best co-surfactant in the diesel micro-emulsion system.The micro-emulsion collector(MD)was prepared with a ratio of emulsifier∶diesel oil∶water as 22.62∶66.71∶10.67.The average particle size of oil droplets was 17.56 nm.The particle size of the mi-croemulsion remains essentially unchanged after centrifugation.The average particle size of MD dispersed in water was 112.4 nm,which was much smaller than 123.88 μm of diesel oil.At the same collector dosage,the micro-emulsion significantly increases the concentrate yield,decreases the ash content,and improves the flota-tion perfection index.To achieve a concentrate yield of 79.45%,the dosage of the MD micro-emulsion collector was 135 g/t lower than that of diesel oil,representing a 45%reduction in collector consumption.Consequently,the flotation collector cost was reduced by 0.44 yuan per ton of dry coal slime.The contact angle tests show that MD can significantly enhance the hydrophobicity of coal particle surfaces,improve their floatability,and con-sequently increase the combustible matter recovery rate.

Abstract:Currently,there are two types of coal washability curves widely used both domestically and interna-tionally:the H-R washability curve and the M curve.To meet the needs of modern coal preparation technology development,this paper,while fully acknowledging the historical significance of these two curves,addresses certain issues in their application—such as coordinate setting,curve function and distribution,graphing methods,and data reading—and proposes a utility model coal washability curve.Compared to existing curves,the struc-ture of this utility model coal washability curve is entirely different:it uses density as the fundamental variable,with clear principles,concise structure,flexible setup,easy graphing,and smooth curves,making it not only con-sistent with human intuition but also convenient for data reading.To verify the validity of the applicability of this new curve,the author tested several representative types of coal,including extremely difficult-to-wash coal with small density grade differences.The results show that the utility model coal washability curve can meet the requirements for coal washability evaluation.Additionally,the paper offers suggestions for improving the exist-ing coal washability grade evaluation rules.

Abstract:To address the issues of high fine coal carry-over in the underflow and high coarse coal loss in the overflow of the hydrocyclones for coarse slime classification at Jiangzhuang Coal Preparation Plant—problems that adversely affected the subsequent performance of the CSS separator and the indicators of flotation tailings—the plant collaborated with China University of Mining and Technology to conduct research on the precise classification of coarse slime.By implementing a technical solution that involved reducing the hydrocyc-lone diameter,introducing secondary rinse water,and developing an intelligent feed control system,the original large-diameter hydrocyclones were replaced with CC-300 high-efficiency classification hydrocyclone units.The results of industrial application showed that the fine coal carry-over in the underflow of the new hydrocyclone units decreased from 35.87%to 22.62%,while the coarse coal loss in the overflow dropped from 8.12%to 1.43%.With the ash content of clean coal remaining largely stable,the clean coal yield of the CSS coarse slime separator increased by over 2 percentage points,generating an additional annual economic benefit of approxim-ately 3.693 9 million yuan.Additionally,the ash content of flotation tailings rose to 80.97%,meeting the calorif-ic value requirements for tailings set by Zaozhuang Mining Group.This improvement provided high-quality feed conditions for the efficient separation of coarse slime.

Abstract:To address issues of low separation efficiency in the coarse coal slime system—which led to easily exceeding the target ash content of clean coal and insufficient production,and to ensure clean coal quality(ash content≤8.5%)while enhancing the economic performance of the plant,Yangjiaqu Coal Preparation Plant op-timized the system through a"problem diagnosis-stepwise renovation"approach.Specific measures included:conducting particle size distribution,infrared spectroscopy,and XRD analysis of the hydroclassification feed;re-placing damaged screen plates on the desliming screen and modifying the pneumatic agitation system of the cyc-lone feed tank to reduce contamination by greater than 1 mm coarse particles;implementing a closed-loop intel-ligent control system for the hydrocyclone based on"density-pressure"(target density 250±10 g/L,pressure 0.15±0.02 MPa)to minimize fine coal loss in the underflow;and equipping the spiral concentrator with an automatic water replenishment device for the underflow box while adjusting the cutter position to 300 mm from the central axis to reduce misplacement rates.Production practice shows that:the yield of>1 mm particles in the hydroclassification feed decreased from 13.99%to 3.06%;the proportion of<0.25 mm particles in the cyclone underflow dropped by 12.16 percentage points;the clean coal yield of the spiral concentrator increased from 45.84%to 70.54%,a gain of 24.7 percentage points,with ash content consistently meeting standards.Economic-ally,the renovation added annual benefits of 91.46 million yuan compared to a middlings-dominated product scenario and 54.70 million yuan compared to the existing blending method.The renovation effectively resolved core issues in the coarse coal slime separation system,ensuring both quality and yield of clean coal.The technic-al approach offers a reliable reference for optimizing similar coarse coal slime systems in low-rank thermal coal preparation plants.

Abstract:Aiming at the widespread issue of poor sedimentation in coal slurry water treatment leading to high concentration in the circulating water system,this study takes the feed coal slurry water(with D50 of 26.61 μm,high fine particle mass fraction,and difficult sedimentation)from the thickener at Zhaozhuang Coal Preparation Plant as the research subject.Using supernatant transmittance,initial sedimentation rate,and compressed layer thickness as the evaluation criteria for flocculation sedimentation,and combining methods such as Zeta poten-tial and Focused Beam Reflectance Measurement(FBRM),the effects of cationic polyacrylamide(CPAM),an-ionic polyacrylamide(APAM),nonionic polyacrylamide(NPAM)alone and their combination with polyalumin-um chloride(PAC)on coal slurry water sedimentation were investigated.The results show that PAC,as an inor-ganic polymer coagulant,possesses hydrolysis products with strong adsorption and bridging effects,which syn-ergize with CPAM to significantly enhance the aggregation capacity of coal slurry particles.When PAC dosage is 50 g/t,the sedimentation rate reaches 75.38 cm/min,an increase of 6.7 cm/min compared to using CPAM alone;the compressed layer thickness decreases to 4.5 cm,and the transmittance improves to 96.2%.FBRM tests indicate that the floc size under the combined action of PAC and CPAM increases significantly.Therefore,the combination of PAC and CPAM achieves the best flocculation sedimentation effect,addressing sedimenta-tion challenges through charge neutralization and bridging synergy.This study provides theoretical and practical support for coal slurry water treatment in coal preparation plants.