Cradle to Gate
Identity ID
4243dfb9-a47f-4e14-a247-65ee7551ee01
Materials
Associated ID
c1c0455a-9c3b-44c8-afe2-39256c080fc0
Included activities starts
Included activities ends
Description
This dataset represents a life cycle inventory (cradle-to-gate) of the coal washing process starting from dense medium separation to the production of clean coal, covering all activities associated with coal beneficiation. However, it does not include situations outside the coal preparation plant (such as raw coal mining, utilization of clean coal), or direct and indirect greenhouse gas emissions arising from employee 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 Selection Industry" (HJ 446-2008) and the "Coal Industry Pollutant Discharge Standard", this dataset was compiled from multiple data sources and is representative of the average production level in Shanxi.
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
Shanxi Province's steam coal is widely distributed in the Taiyuan Formation, Shanxi Formation, and Datong Formation. The Taiyuan and Shanxi Formations are mainly lean coal and anthracite, while the Datong Formation is primarily weakly caking coal. The Taiyuan Formation has an ash content of 12.62–28.52%, volatile matter of 6.5–14.79%, maximum thickness of the plastic layer at 0 mm, total sulfur in raw coal of 1.2–6.65%, and a net calorific value on an as-received basis (Qnet,ar) of 8136–8749 kcal/kg. The Shanxi Formation has an ash content of 8–35%, volatile matter in raw coal of 6.4–16.6%, maximum thickness of the plastic layer of 0–12 mm, and total sulfur in raw coal of 0.2–0. 92%, with a received basis net calorific value (Qnet,ar) of 8,350~8,577 kcal/kg. Datong Group raw coal has an ash content of 8.56~16.13%, refined coal volatile matter of 29.73~35.52%, maximum thickness of the vitrinite layer (G-index) of 0 mm, total sulfur content in raw coal of 0.49~1.93%, and a received basis net calorific value (Qnet,ar) of 7,705~7,946 kcal/kg.
Time period
2022
2026
Geography
China,Shanxi
Geography comment
Forming average data for Shanxi Province by 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.