Cradle to Gate
Identity ID
8728b1c0-ccfe-496a-a033-3586719ff694
Materials
Associated ID
a1a1a3f0-7fd7-4e13-81a9-8932939cdded
Included activities starts
Included activities ends
Description
This dataset represents the full life cycle inventory (cradle-to-gate) of magnetite ore processed via a "three-stage closed-circuit crushing, multi-stage grinding, and magnetic separation" method in Hunan, covering all activities related to the beneficiation production of hematite concentrate. However, it does not include direct or indirect greenhouse gas emissions from the production of crushing equipment, magnetic separation equipment, personnel commuting, or daily office operations during the beneficiation process. The dataset was compiled from multiple data sources based on national standards such as the 'Manual of Production and Emission Coefficients for the Iron Ore Mining and Processing Industry (0810)', 'Emission standard of pollutants for mining and mineral procressing industry (GB 28661-2012)', 'Cleaning production standard Iron ore mining and mineral processing industry', and 'The norm of the energy consumption per unit product of iron ore dressing(GB31337-2014)', and is representative of the average production level of magnetite processing involving three-stage closed-circuit crushing, multi-stage grinding, and magnetic separation in Hunan.
Activity Description
This dataset describes the processing of magnetite and hematite in Hunan Province using a "three-stage closed-circuit crushing-multi-stage grinding-magnetic separation" process. The production flow is as follows:
1. Three-stage closed-circuit crushing:
Coarse crushing: The raw ore is first coarsely crushed using a jaw crusher, with the particle size generally controlled at around 100-150 mm.
Medium crushing: The coarsely crushed ore enters a cone crusher for medium crushing, further reducing the particle size to 25-50 mm.
Fine crushing: The medium-crushed ore enters a cone crusher or impact crusher for fine crushing, with the particle size generally controlled at 8-15 mm.
Closed-circuit screening: The finely crushed ore is screened using a vibrating screen. Qualified ore enters the grinding process, while ore that does not meet the particle size requirements is returned to the crushing system for reprocessing.
2. Multi-stage grinding:
Single-stage ball milling: The ore is ground in a ball mill, typically to a particle size of 0.2-0.3 mm.
Classification: The slurry after grinding is classified using a spiral classifier or hydrocyclone. Qualified slurry proceeds to the next step, while coarse particles are returned to the ball mill for regrinding.
Secondary Ball Milling: After primary grinding, the ore undergoes secondary grinding to achieve a finer particle size, typically below 0.074 mm, to ensure sufficient liberation of iron minerals.
Classification Recycling: Unqualified coarse particles are returned to the secondary ball mill for further grinding, while qualified fine particles enter the magnetic separation process.
3. Multi-Stage Magnetic Separation
3.1 Magnetite Magnetic Separation
Preliminary Magnetic Separation: The slurry after primary grinding first enters a wet magnetic separator for preliminary separation. Magnetic minerals are adsorbed by the magnetic separator, while non-magnetic substances are discharged as tailings.
Fine Magnetic Separation: The magnetic minerals after preliminary separation enter a further fine magnetic separation process. Magnetic substances are further enriched and purified into iron concentrate in the magnetic separator.
Tailings Treatment: Tailings after magnetic separation are treated through tailings ponds or other methods to ensure resource utilization and environmental protection.
3.2 Hematite Magnetic Separation
Due to the weak magnetic properties of hematite, strong magnetic separation is typically used to extract iron minerals:
Strong Magnetic Separation: A strong magnetic separator is used in the slurry after secondary grinding. The strong magnetic field enriches the hematite.
Reverse Flotation (Optional Step): For some hematite, reverse flotation is usually performed after magnetic separation to further remove impurities and improve the grade of the iron concentrate.
4. Concentrate Dewatering and Product Transportation
Dewatering Process: The iron concentrate obtained after magnetic separation contains a large amount of water. Vacuum filters, filter presses, or ceramic filters are typically used for dewatering to ultimately control the moisture content below 10%.
Process Description
In this dataset, the iron ore concentrate has a grade of 64%, belongs to transition metals, and is the main product of the mineral processing stage. Iron ore concentrate is typically in powder form and is widely used in downstream processing at sintering and pelletizing plants, serving as a key raw material in steel production.
Time period
2022
2026
Geography
China,Hunan
Geography comment
Forming Hunan's average data through merging data from multiple sources
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
The three-stage closed-circuit crushing, multi-stage grinding, and magnetic separation process in China is widely applied in the beneficiation of magnetite and hematite. This process effectively separates iron minerals from iron ore and removes impurities through multiple stages of crushing, grinding, and magnetic separation, thereby improving the grade of iron concentrate. This technology is particularly suitable for magnetite and hematite with high iron content but associated with a large amount of impurities.