Cradle to Gate
Identity ID
79354f9c-51ef-4d62-b153-c4cae71f9442
Materials
Associated ID
fcd37d36-d3d8-4ca3-8932-0016d9b48641
Included activities starts
Included activities ends
Description
This dataset represents the life cycle inventory (cradle-to-gate) of staged grinding and staged magnetic separation for magnetite ore in Inner Mongolia, covering all activities related to iron concentrate beneficiation production from the crushing stage to the 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 transportation, 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 stage grinding-stage magnetic separation for magnetite in Inner Mongolia.
Activity Description
This dataset describes a staged grinding-stage magnetic separation process for iron ore, with the following workflow:
1. Crushing and Pretreatment
Crushing: Before entering the grinding stage, iron ore typically undergoes a three-stage closed-circuit crushing process or similar crushing method to break large ore pieces to a suitable grinding size (usually below 10-15 mm).
Pretreatment: After crushing, the ore may undergo preliminary screening to remove large gangue particles. In some cases, dry pre-selection may also be performed to reduce the amount of ore entering the grinding stage and lower subsequent processing costs.
2. First-Stage Grinding
Process Purpose: The purpose of the first-stage grinding is to further refine the ore, achieving preliminary liberation of mineral particles to facilitate subsequent magnetic separation. Typically, the first-stage grinding uses a ball mill or rod mill to grind the ore to a fineness of **0.074 mm accounting for 50%-60%**.
Grinding Equipment: Commonly used equipment includes ball mills or rod mills. The appropriate grinding method is selected based on the hardness of the ore and the grinding requirements.
Magnetic Separation: After the first stage of grinding, the slurry enters a weak magnetic separator. The main task of magnetic separation at this stage is to separate the liberated iron minerals, initially improving the concentrate grade. The concentrate after weak magnetic separation proceeds to the next stage of processing, while the tailings are discarded or sent to a tailings dam.
3. Second Stage Grinding
Process Objective: The main objective of the second stage of grinding is to further refine the mineral particles in the slurry to improve the magnetic separation effect. The grinding fineness at this stage typically requires 70%-85% of the particles to be -0.074mm, ensuring more thorough mineral liberation.
Grinding Equipment: The second stage usually still uses a ball mill, and a classifier or hydrocyclone may be added for slurry classification to ensure the required fineness is achieved.
Magnetic Separation: After the second stage of grinding, the slurry re-enters the magnetic separator for further refining. The goal of magnetic separation at this stage is to further improve the grade of iron minerals and remove gangue minerals as much as possible. The concentrate after magnetic separation is conveyed to the next stage, while the tailings are further processed.
4. Third-Stage Grinding and Magnetic Separation
Process Purpose: The third-stage grinding typically requires a higher fineness, usually reaching over 90% -0.074mm. This is to ensure sufficient mineral liberation, completely separating iron minerals from gangue. After this stage, the grade of the iron concentrate is significantly improved.
Grinding Equipment: This stage often uses high-efficiency ball mills or tower mills to further refine the mineral particles. Before entering the third-stage grinding, the slurry is usually screened by classifying equipment to ensure grinding efficiency and fineness requirements.
Magnetic Separation: The third-stage magnetic separation is the final step in the entire process. High-efficiency magnetic separators are used for fine selection, further purifying the concentrate. At this point, the magnetically separated concentrate basically meets the quality requirements for iron concentrate powder, and the tailings are ultimately discarded.
5. Concentrate Dewatering and Recovery
Concentrate Dewatering: After passing through multiple stages of magnetic separation, the concentrate needs to undergo dewatering treatment. Commonly used equipment includes vacuum filters, ceramic filters, or disc filters to reduce the moisture content of the concentrate, making it easier to transport and store.
Recovery: The iron content of the dehydrated iron concentrate is typically between **65% and 69%**, meeting the needs of smelting enterprises, and is ultimately transported to the smelter for steel production.
6. Tailings Treatment
Tailings treatment: The tailings produced after magnetic separation have a low iron content and are usually centrally stored in tailings ponds or treated using dry discharge technology to reduce the environmental impact of tailings. In some mines, tailings may be further utilized, for example, in building materials or backfilling.
Process Description
The iron concentrate in this dataset has a grade of 66%, belongs to transition metals, and is the primary product of the mineral processing stage. Typically in powder form, iron concentrate is widely used in downstream processing operations at sintering and pelletizing plants, serving as a key raw material for steel production.
Time period
2022
2026
Geography
China,Inner Mongolia Autonomous Region
Geography comment
Forming average data for Inner Mongolia through data consolidation from multiple sources
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
The staged grinding and staged magnetic separation process refers to treating the ore through multiple grinding stages, followed by magnetic separation operations at each stage to progressively extract the iron minerals. Each stage of grinding and magnetic separation aims to fully liberate the iron minerals and separate them from gangue minerals, thereby meeting the final concentrate specifications.