Cradle to Gate
Identity ID
dc014d22-1546-48b0-84f9-8b58b4d5bab6
Materials
Associated ID
2345bea7-7cd0-4ec1-9e86-20baeaf9bda7
Included activities starts
Included activities ends
Description
This dataset represents the life cycle inventory from the beginning of jig coal washing to the production of clean coal (cradle-to-gate), covering all activities associated with coal washing, but excluding situations external to the coal washing plant (such as raw coal mining, use of clean coal), and direct or indirect greenhouse gas emissions arising from personnel commuting and daily office operations during the coal washing process. Based on national standards such as the "Clean Production Standard for Coal Mining and Washing Industry" (HJ 446-2008) and the "Pollutant Emission Standards for the Coal Industry", this dataset was compiled from multiple data sources and is representative of the average production level in Shanxi.
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
Shanxi Province's steam coal is widely distributed in the Taiyuan Formation, Shanxi Formation, and Datong Formation, among which the Taiyuan Formation and Shanxi Formation are primarily lean coal and anthracite, while the Datong Formation is mainly weakly caking coal. The Taiyuan Formation has an ash content of 12.62–28.52%, volatile matter of 6.5–14.79%, a maximum plastic layer thickness of 0 mm, total sulfur in raw coal of 1.2–6.65%, and a calorific value 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%, a maximum plastic layer thickness of 0–12 mm, and total sulfur in raw coal of 0.2–. 92%, calorific value 8350~8577 kcal/kg. Datong Formation raw coal ash content 8.56~16.13%, refined coal volatile matter 29.73~35.52%, maximum thickness of the vitrinite layer 0 mm, raw coal total sulfur 0.49~1.93%, Qnet,ar gross as-received low calorific value 7705~7946 kcal/kg.
Time period
2022
2026
Geography
China,Shanxi
Geography comment
Forming Shanxi's average data through the integration of data from multiple sources.
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.