Cradle to Gate
Identity ID
560d6dd3-8945-47a0-a741-ab8e603b200c
Materials
Associated ID
e1d40d73-150c-4678-ab85-3fba62a77476
Included activities starts
Included activities ends
Description
This dataset represents the full magnetic separation technology for processing magnetite in China. It covers the life cycle inventory (cradle-to-gate) from crushing to the production of hematite concentrate, including all activities related to iron ore beneficiation production, but excluding the direct or indirect greenhouse gas emissions from the production of crushing equipment, magnetic separation equipment, personnel travel, and daily office operations during the beneficiation process. The dataset is 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)'. It represents the average production level of China's magnetite processing using full magnetic separation technology.
Activity Description
This dataset describes the processing of magnetite using a full magnetic separation technology, with the following process flow:
1. Ore Crushing
Coarse Crushing: Large ore chunks are crushed to particles smaller than 200mm using a jaw crusher.
Medium and Fine Crushing: The crushed ore is then fed into a cone crusher or impact crusher for medium and fine crushing, with the final particle size controlled at 8-15mm, suitable for the grinding stage.
2. Stage Grinding
First Stage Grinding: The ore first enters a ball mill for first-stage grinding, typically controlling the grinding fineness to **70%-80% -0.074mm**. The main purpose of this stage is to initially liberate iron minerals and gangue minerals.
Second Stage Grinding: The grinding product is classified using a classifier or hydrocyclone. Unqualified coarse particles enter the second stage grinding, which typically requires a fineness of **over 90% -0.074mm**. This step ensures further refinement and liberation of the mineral particles.
Third-stage grinding (optional): For complex ores requiring high-grade iron concentrate, a third-stage grinding process may be necessary. The fineness of the third-stage grinding is generally controlled to be at least 90% -0.037mm to ensure complete liberation of mineral particles, especially for ores with high impurity content.
3. Weak magnetic separation (preliminary magnetic separation)
Process description: After one or two stages of grinding, the slurry enters a weak magnetic separator (such as a wet magnetic separator). Magnetic iron minerals are adsorbed by the magnetic separator drum, while gangue minerals are discharged with the slurry. Through preliminary weak magnetic separation, the grade of the iron concentrate can be increased to 50%–60%.
4. Fine screening and regrinding
Process description: The slurry after weak magnetic separation is screened using a high-efficiency fine screen (such as a high-frequency vibrating screen). Qualified particles directly enter the next stage of the refining process, while unqualified coarse particles are returned to the regrinding mill for secondary or tertiary grinding to ensure complete liberation of iron minerals from gangue.
Grinding Fineness Requirements: At this stage, the grinding fineness typically reaches over 90% for particles smaller than -0.074mm, and can even be further reduced to over 90% for particles smaller than -0.037mm, ensuring complete refinement of iron mineral particles.
5. High-Efficiency Magnetic Separation
High-Frequency Vibrating Screen: Used to screen the refractory slurry, ensuring uniform particle size. High-frequency vibration removes residual gangue minerals from the ore, ensuring uniform particle size in the slurry entering the magnetic separation process.
Magnetic Separation Column: Utilizes a strong magnetic field to further separate iron minerals from the gangue, ensuring a final iron concentrate grade of 67%~69.5%. The strong magnetic field of the magnetic separation column effectively captures low-magnetic iron minerals, further improving the purity of the iron concentrate.
Disc Filter: Used for dewatering the refined slurry. The disc filter removes moisture from the concentrate, yielding a concentrate product with low water content (typically controlled below 10%), facilitating subsequent transportation and storage.
6. Tailings Treatment and Concentrate Recovery
Tailings Treatment: After high-efficiency magnetic separation, the remaining tailings have a low iron content (usually controlled below 10%) and are mainly used for filling or other waste disposal. Tailings are treated through tailings storage or dry discharge technology to reduce environmental impact.
Concentrate Recovery: After multiple beneficiation and dewatering processes, high-grade iron concentrate is finally obtained, with a grade reaching 67%~69.5% and SiO₂ content reduced to below 4%, meeting the production requirements of high-quality iron concentrate. The concentrate is transported to the concentrate bin via belt conveyor or grab bucket, awaiting external shipment or smelting.
Process Description
The iron concentrate in this dataset has a grade of 68%, belongs to transition metals, and is the main product of the mineral beneficiation process. Iron concentrate is typically in powder form and is widely used in downstream processing industries such as sintering plants and pelletizing plants, serving as a key raw material for steel production.
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
Full magnetic separation technology refers to further concentration using high-efficiency fine screens and high-efficiency magnetic separators, based on the existing process stages of grinding, low-intensity magnetic separation, and fine screening with regrinding and re-separation. Key high-efficiency magnetic separation equipment includes high-frequency vibrating screen, magnetic separators, magnetic separation columns, and disc filters. Technology applicability and characteristics: This technology can improve metal recovery rates and reduce pollution at the source. Implementing this technology enables iron concentrate grade to reach 67%--69.5%, with SiO₂ content below 4%.