Cradle to Gate
Identity ID
556c6675-e81c-4ff2-8bb0-cbbf97dc1aff
Materials
Associated ID
ad42cb41-07a7-42ef-abda-6c68126bde52
Included activities starts
Included activities ends
Description
This dataset represents the life cycle inventory (cradle-to-gate) for the production of middlings coal from combined coal beneficiation processes involving jigs and flotation. It covers all activities related to coal washing, but excludes external conditions beyond the coal preparation plant (such as raw coal mining, utilization of Clean coal), as well as direct or indirect greenhouse gas emissions from personnel travel and daily office operations during the coal washing process. Based on national standards including "Cleaner Production Standard for the Coal Mining and Washing Industry" (HJ 446-2008) and "Emission Standards of Pollutants for the Coal Industry", this dataset was compiled from multiple data sources and reflects the average production level in China.
Activity Description
This dataset describes the combined coal preparation process using jigging and flotation, which integrates both jigging and froth flotation methods. It is primarily used for processing coal of varying particle sizes and qualities to achieve optimal separation efficiency. Below is a detailed description and introduction of the entire production process for the combined jigging and flotation coal preparation:
1. Raw Coal Preparation
Coal Crushing and Screening:
Raw coal is first crushed by crushers into particles suitable for jigging and flotation. Generally, coarse-sized coal (above 50 mm) is subjected to jigging separation, while fine-sized coal (0.5–50 mm) and slimes (below 0.5 mm) are processed by flotation. are subjected to flotation separation. The crushed coal is classified by size using screening equipment, and coal of different sizes is sent to the corresponding coal preparation equipment. 2. Jigging Separation
Jig Preparation:
Coarse and medium-sized coal is separated through a jig. The jig uses pulsating 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:
Coal enters the jig's feed hopper and mixes with water to form a slurry. Under the action of the jig, clean coal and impurities are stratified. Clean coal is collected via overflow troughs or discharge mechanisms, while impurities are discharged through the discharge outlet. Flotation Separation
Grinding:
Medium and fine coal particles need further grinding before entering the flotation machine to achieve a suitable particle size for flotation (typically below 0.1 mm).
Flotation Reagent Addition:
The ground coal powder is mixed with water to form a slurry, and flotation reagents (such as collectors, frothers, and modifiers) are added before being fed into the flotation cell.
Flotation Process:
In the flotation cell, bubbles are generated through mechanical agitation and air injection. Coal particles attach to the bubbles and rise to the surface of the slurry, forming a froth layer. This froth layer is collected to obtain high-purity clean coal. Clean coal processing
Dewatering:
After jigging and flotation coal preparation, clean coal contains certain moisture and requires dewatering using dewatering equipment (e.g., dewatering screens, centrifuges, or filter presses) to reduce moisture content and improve clean coal quality.
Storage and transportation:
Dewatered clean coal is stored and transported. To prevent dampness and spontaneous combustion during storage and transportation, protective measures must be taken, such as using coal sheds or sealed stockyards for storage. Tailings Management
Tailings Disposal:
The tailings generated during jigs and flotation processes (mainly gangue and impurities) are discharged through discharge equipment and transported to the tailings management area.
Tailings Dewatering and Wastewater Treatment:
The moisture in the tailings needs further processing. After dewatering using thickeners or filters, the solid tailings are stored or further processed. The wastewater generated during the flotation process is treated and then either recycled or discharged in compliance with environmental standards to minimize environmental pollution.
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
Jigging and flotation combined coal washing is an efficient and flexible coal preparation process that effectively handles coal of different particle sizes and qualities by combining jigging and flotation methods. Its production process includes coal crushing and screening, jigging separation, grinding, flotation separation, clean coal processing, and tailings management. This process 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.