Cradle to Gate
Identity ID
a5efa374-5c0a-47c0-b879-2f3a983eac9c
Materials
Associated ID
be9c8da4-3045-4adc-81f8-98d2d832eb83
Included activities starts
Included activities ends
Description
This dataset represents the life cycle inventory (cradle-to-gate) for the process of coal preparation combining jigging and dense medium separation to produce cleaned thermal coal, covering all activities related to coal washing, but excluding external conditions beyond the coal preparation plant (such as raw coal mining, coal utilization, etc.), as well as direct or indirect greenhouse gas emissions from personnel commuting and daily office operations during the coal preparation process. Based on national standards such as the "Cleaner Production Standard for the Coal Mining and Washing Industry" (HJ 446-2008) and the "Emission Standards for Pollutants in the Coal Industry", the dataset was compiled from multiple data sources and is representative of the average production level in Inner Mongolia.
Activity Description
This dataset describes the combined jigger and heavy medium coal preparation, a process that integrates both jigging and heavy medium coal preparation methods. It is primarily used to process coal of varying particle sizes and qualities to achieve optimal separation efficiency. Below is a detailed description and introduction of the entire production process of the combined jigger and heavy medium coal preparation:
1. Raw Coal Preparation
Coal Crushing and Screening:
Raw coal is first crushed by crushers into particles suitable for jigger and heavy medium coal preparation. Generally, coarse-sized coal (above 50 mm) undergoes jigger separation, while medium-sized coal (0. Coal with a size range of 5-50 mm undergoes dense medium coal washing. After crushing, coal is classified by size using screening equipment, and coal of different size fractions is sent to corresponding coal preparation equipment. Jigging Separation
Jig Preparation:
Coarse coal is separated using a jig. The jig utilizes the pulsating action of water to stratify coal and impurities based on density. The lighter clean coal rises to the upper layer, while the heavier gangue and impurities sink to the lower layer.
Separation Process:
The coal enters the jig's feed hopper, where it is mixed with water to form a slurry. Under the action of the jig, the clean coal and impurities are separated into layers. The clean coal is collected via an overflow chute or discharge device, while the impurities are discharged through the discharge outlet.
3. Heavy Medium Separation
Preparation of heavy medium suspension:
Mix magnetite powder or other heavy medium materials with water to prepare a heavy medium suspension of a specific density. The density of the suspension is adjusted according to the density difference between coal and impurities.
Coal separation:
Medium-sized coal particles are separated using a heavy medium separator. In the heavy medium suspension, coal with lower density floats, while impurities with higher density sink, thereby achieving separation of coal and impurities.
The light product (clean coal) and heavy product (impurities) are discharged through separate outlets after separation.
Recovery of heavy medium:
The heavy medium suspension after separation is processed through a magnetic separator to recover the magnetite powder for recycling. The recycled medium materials are reintroduced into the preparation process.
4. Clean Coal Processing
Dewatering:
Clean coal produced from jigging coal preparation and dense medium coal preparation contains a certain amount of moisture. It must be dewatered using dewatering equipment (such as dewatering screens, centrifuges, or filter presses) to reduce moisture content and improve the quality of clean coal.
Storage and Transportation:
After dewatering, the clean coal is stored and transported. To prevent moisture absorption and spontaneous combustion during storage and transportation, protective measures should be implemented, such as storing in coal sheds or sealed stockyards.
5. Tailings Management
Tailings Disposal:
The tailings (mainly gangue and impurities) generated during jigger and heavy medium coal preparation processes are discharged via discharge equipment to the tailings management area.
Tailings Dewatering and Wastewater Treatment:
The moisture in the tailings needs further processing. After dewatering using thickeners or filters, solid tailings are stored or further processed. The wastewater generated during the heavy medium coal preparation process is treated for recycling or for discharge in compliance with environmental standards, thereby reducing environmental pollution.
Process Description
Inner Mongolia thermal coal is mainly distributed in the Pingzhuang coalfield, Zhalainuoer coalfield, Huolinhe coalfield, Yiminhe coalfield, Dayan coalfield, Daqingshan coalfield, Chenqi coalfield, various coalfields in Xilingol League, Dongsheng coalfield, and Zhungeer coalfield. Moisture content ranges from 4.11% to 18.52%, ash content from 4.02% to 47%, volatile matter from 2.9% to 49.73%, total sulfur from 0.09% to 1.42%, phosphorus content from 0.001% to 0.208%, and the net calorific value on an as-received basis (Qnet,ar) ranges from 6,525 to 8,224 kcal/kg.
Time period
2022
2026
Geography
China,Inner Mongolia Autonomous Region
Geography comment
Forming average data for Inner Mongolia through data consolidation from multiple sources
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
jigging and dense medium integrated coal preparation is an efficient and flexible coal processing technology. By integrating jigging and heavy middlings separation methods, it can effectively handle coal of different particle sizes and qualities. The production process includes coal crushing and screening, jigging separation, heavy middlings separation, clean coal processing, and tailings treatment. This technology significantly improves coal purity and utilization efficiency, offering high processing capacity, high separation efficiency, and environmental friendliness, and is widely applied in coal preparation plants.