Cradle to Gate
Identity ID
c9001141-58cd-4fdb-bb25-d95280ade3be
Materials
Associated ID
ae258882-875f-4ae3-9958-e0ff6571d288
Included activities starts
Included activities ends
Description
This dataset represents the life cycle inventory (cradle-to-gate) of hematite processing in China using continuous grinding, magnetic separation-anionic reverse flotation technology, covering all activities related to iron concentrate beneficiation production from crushing 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 travel, and daily office operations during the beneficiation process. The dataset was compiled from multiple data sources based on Chinese national standards including 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 in China for processing hematite using continuous grinding, magnetic separation, and anionic reverse flotation technology.
Activity Description
This dataset describes the processing of hematite using continuous grinding, magnetic separation-anion reverse flotation technology, with the following process flow:
1. Continuous Grinding
Process Description: Continuous grinding typically involves two stages. The ore is first coarsely crushed and then medium crushed before entering the continuous grinding system for two stages of grinding:
Stage 1 Grinding: The ore is ground to a finer particle size using a ball mill, ensuring initial liberation of mineral particles. The grinding fineness at this stage is typically controlled at **70%~80% -0.074mm**.
Stage 2 Grinding: The slurry from the first stage grinding enters the second stage grinding, further refining the mineral particles and ensuring sufficient liberation of iron minerals from gangue minerals. The fineness of the second stage grinding is typically required to reach **over 90% -0.074mm** to ensure the efficiency of subsequent beneficiation operations.
Grinding Fineness Control: The final grinding fineness of the entire grinding system reaches **over 90% -0.074mm**, providing a stable particle size base for subsequent magnetic separation and flotation.
Results: Through two-stage continuous grinding, the degree of mineral particle liberation is significantly improved. The thorough liberation of iron minerals from gangue minerals ensures effective subsequent magnetic separation and flotation.
2. Magnetic Separation Operation
Process Description: The ground slurry enters the magnetic separation process, employing a combination of weak and strong magnetic separation:
Weak Magnetic Separation: First, a weak magnetic field separator recovers the strongly magnetic iron minerals. This step effectively removes most of the gangue, yielding a pre-enriched iron concentrate.
Strong Magnetic Separation: The slurry after weak magnetic separation undergoes further enrichment using a strong magnetic field separator, further separating the weakly magnetic iron minerals and improving the grade of the iron concentrate.
Results: Magnetic separation removes most of the gangue minerals, significantly improving the grade of the iron concentrate and noticeably reducing the gangue mineral content, providing high-grade raw material for subsequent flotation operations.
3. Anion Reverse Flotation
Process Description: The iron concentrate pulp after magnetic separation enters the flotation process using anion reverse flotation:
Collector Selection: Anion reverse flotation typically uses anion collectors (such as fatty acids, phosphates, etc.) to selectively float gangue minerals. The collector reacts with the surface of the gangue minerals, causing them to float, while the iron minerals settle.
Flotation Process: Through steps such as reagent addition and agitation, and bubble flotation, gangue minerals and iron minerals are separated. The gangue minerals are thrown out as flotation froth, while the iron minerals are recovered as concentrate.
Iron Recovery and Grade: The iron recovery rate of anion reverse flotation can typically reach over 90%, and the grade of the flotation-processed iron concentrate can be increased to 67%~68%.
Effects: Anion reverse flotation effectively removes impurities from iron minerals, improves the purity of the iron concentrate, and ensures the production of high-grade iron concentrate, suitable for high-quality smelting requirements.
4. Tailings Treatment and Concentrate Recovery
Tailings Treatment: The iron content of the tailings after flotation is typically reduced to 8%–9%. After treatment in tailings ponds or dry discharge technology, tailings emissions are reduced, meeting environmental standards.
Concentrate Recovery: The iron concentrate after flotation enters a dewatering process, typically using ceramic filters or other high-efficiency filtration equipment to reduce the moisture content to below 10%, facilitating subsequent storage and transportation.
Process Description
The iron concentrate in this dataset has a grade of 67.5%, 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 at sintering and pelletizing plants, serving as a key raw material in 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
Continuous grinding, magnetic separation-anionic reverse flotation technology refers to the beneficiation process in which ore is subjected to continuous grinding to fully liberate minerals, followed by magnetic separation, flotation, and other separation processes. Applicability and characteristics of the technology: This technology provides stable grinding particle size and high separation efficiency, enables efficient resource utilization, and reduces pollution at the source. The technology not only increases the iron grade of the material fed into the anionic reverse flotation process but also reduces the amount of ore, thus creating favorable conditions for the flotation operation; the iron recovery rate in the flotation process exceeds 90%. The concentrate from weak magnetic separation and strong magnetic separation is combined and fed into flotation, avoiding the impact of FeO variations in the ore on beneficiation performance. This technological process is compact, requires fewer equipment, and facilitates production operation and management. Using this technology, the iron concentrate grade can reach 67%--68%, while the tailings grade can be reduced to 8%--9%. However, the entire run-of-mine ore must undergo two-stage continuous grinding, resulting in high energy consumption, high steel ball consumption, and high operating costs. This technology is suitable for lean hematite ores.