Cradle to Gate
Identity ID
669831dd-72b4-46ff-a7d0-6aab1987c0bd
Materials
Associated ID
907fe8d8-e3a6-4db9-8daa-49790403ea93
Included activities starts
Included activities ends
Description
This dataset represents a life cycle inventory (cradle-to-gate) for the coal preparation process, starting from jig coal washing through to the production of Clean coal. It covers all activities related to coal washing, but excludes external aspects beyond the coal preparation plant boundary (such as raw coal mining and coal consumption), as well as direct or indirect greenhouse gas emissions arising from employee commuting and daily office operations during the coal preparation process. The dataset, compiled from multiple data sources, is based on national standards including the "Cleaner Production Standard for the Coal Mining and Washing Industry" (HJ 446-2008) and the "Emission Standards for Pollutants from Coal Industry", and is representative of average production levels in China.
Activity Description
This dataset describes jig coal washing, a physical coal beneficiation method that separates coal from impurities based on their different sedimentation rates in water. It is primarily used for processing lump coal and medium-sized coal particles. The specific process is as follows:
1. Raw coal preparation
Coal crushing and screening:
Raw coal is crushed by a crusher into particles suitable for jig coal washing, typically with a particle size ranging from 0.5 mm to 50 mm. The crushed coal then enters screening equipment for size classification. Coal particles within the appropriate size range are sent to the jig, while those outside this range are directed to corresponding processing units.
2. Jigging Separation
Preparation of the Jigging Machine:
The jigging machine is the core equipment in coal jigging. It periodically pushes water upward through the bed, causing coal and impurities to separate based on their different settling velocities in water. An appropriate jigging machine model should be selected based on the particle size of the coal to be processed.
Feeding of the Ore:
The screened coal is fed uniformly into the feed hopper of the jigging machine and mixed with water to form a slurry.
Separation Process:
The jigging machine uses the pulsating action of water to stratify the ore particles in the bed according to density. Low-density clean coal rises to the upper layer, while high-density gangue and impurities settle to the lower layer. At the bottom of the jig machine, a discharge device is installed to remove gangue and impurities from the lower layer, while the cleaned coal from the upper layer is collected through an overflow chute or other discharge devices.
3. Cleaned Coal Processing
Dewatering:
After jigging, the cleaned coal still contains a certain amount of moisture. Dewatering equipment (such as dewatering screens, centrifuges, or filter presses) is used to reduce the moisture content and improve the quality of the cleaned coal.
Storage and Transportation:
The dewatered cleaned coal is then stored and transported. To prevent moisture absorption and spontaneous combustion during storage and transportation, protective measures should be taken, such as storing in coal sheds or enclosed stockyards.
4. Tailings Management
Tailings Discharge:
The tailings generated during the jig coal washing process (mainly gangue and impurities) are discharged via discharge equipment and transported to the tailings management area.
Tailings Dewatering and Wastewater Treatment:
The moisture contained in the tailings is further processed through thickeners or filters for dewatering. The solid tailings are then stockpiled or subjected to further processing. The wastewater produced during the jig coal washing process is treated for recycling or for discharge in compliance with environmental standards, thereby reducing environmental pollution.
Process Description
Cleansed coal refers to high-quality coal that has been processed in a coal preparation plant, reducing ash and sulfur content and removing certain impurities, making it suitable for specific applications.
Time period
2022
2026
Geography
China
Geography comment
Forming China's average data through merging multiple provincial datasets
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
Jig coal washing is an efficient and environmentally friendly physical coal beneficiation method that separates coal from impurities based on their different settling velocities in water. The production process of jig coal washing includes coal crushing and screening, jig separation, clean coal processing, and tailings management. This technology significantly enhances coal purity and utilization efficiency, featuring high processing capacity, low energy consumption, and environmental compatibility. It is widely applied in the beneficiation of lump coal and medium-sized coal particles.