Cradle to Gate
Identity ID
ffff442b-9937-478a-bbce-567f17691f6e
Materials
Associated ID
c1c0455a-9c3b-44c8-afe2-39256c080fc0
Included activities starts
Included activities ends
Description
This dataset represents the life cycle inventory (cradle-to-gate) of the run-of-mine coal processing via dense medium separation up to the production of middlings, covering all activities related to coal washing, but excluding external conditions beyond the coal preparation plant (e.g., raw coal mining, utilization of Clean coal), as well as direct or indirect greenhouse gas emissions from personnel commuting and daily office operations during the coal washing process. Based on Chinese national standards such as "Cleaner Production Standard for the Coal Mining and Washing Industry" (HJ 446-2008) and "Emission Standards of Pollutants for the Coal Industry", the dataset is compiled from multiple data sources and reflects the average production level in China.
Activity Description
This dataset describes heavy medium coal beneficiation, a method that uses a heavy medium suspension to separate coal from impurities. The specific process is as follows:
Coal crushing:
Raw coal is crushed by a crusher into particles suitable for washing, typically below 50 mm. The crushed coal then enters screening equipment for particle size classification.
Preparation of heavy medium suspension:
Magnetite powder or other heavy medium materials are mixed 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:
The crushed coal enters the heavy medium separator. In the suspension, coal with lower density floats while impurities with higher density sink, enabling separation of coal and impurities. The separated light fraction (coal) and heavy fraction (impurities) are discharged through different outlets.
Recovery of dense medium:
The dense medium suspension after separation is processed through a magnetic separator to recover magnetite powder, which is then recycled. The recovered dense medium materials are returned to the preparation stage.
Dewatering:
The separated coal contains a certain amount of moisture and is treated by dewatering equipment such as dewatering screens and centrifuges to reduce moisture content and increase the calorific value of the coal.
Storage and transportation:
After dewatering, the coal is stored and transported. To prevent coal from moisture absorption and spontaneous combustion during storage and transportation, protective measures should be taken, such as using coal sheds or enclosed stockyards for storage.
Process Description
Medium coal is an intermediate product separated in coal preparation plants, with ash content lower than clean coal but higher than coal gangue, and is mostly used as boiler fuel in power plants.
Time period
2022
2026
Geography
China
Geography comment
Forming China's average data through merging data from multiple sources.
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
Heavy middlings coal beneficiation is an effective coal cleaning method primarily used to improve coal quality. This method employs a liquid medium with a density between that of coal and gangue for separation. The separation media used include heavy liquids and suspensions. Currently, both domestically and internationally, suspensions prepared by mixing magnetite powder with water are widely used as the separation medium in coal beneficiation. Heavy middlings coal beneficiation involves several steps, including coal crushing, preparation of the heavy middlings suspension, coal separation, recovery of the heavy middlings, and dewatering processes.