Cradle to Gate
Identity ID
de33b61a-4bef-48d9-b3f2-ca486729911d
Materials
Associated ID
d43dfaed-9b6c-4d4f-8779-c181dc779c47
Included activities starts
Included activities ends
Description
This dataset represents the life cycle inventory (cradle-to-gate) of magnetite ore processed via grinding, low-intensity magnetic separation, and reverse flotation in China, covering all activities related to iron concentrate beneficiation production from the crushing stage to the final product. However, it excludes greenhouse gas emissions, either direct or indirect, associated with the production of crushing and magnetic separation equipment, personnel commuting, and 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)'. It represents the average production level in China for stage grinding, low-intensity magnetic separation followed by reverse flotation of magnetite ore.
Activity Description
This dataset describes a staged grinding and weak magnetic separation-reverse flotation process for magnetite, with the following workflow:
1. Staged Grinding
Stage 1 Grinding: The ore is crushed and enters the stage 1 grinding process. The grinding fineness in the first stage is typically controlled at **60%~70% -0.074mm**. The purpose of this stage is to liberate most of the iron minerals, facilitating preliminary enrichment by subsequent weak magnetic separation.
Stage 2 Grinding: The slurry after stage 1 grinding is classified by a hydrocyclone or spiral classifier. The coarse particles from the classification enter the stage 2 grinding process. The grinding fineness requirement in the second stage is higher, typically controlled at **85%~90% or more -0.074mm**. The purpose of this step is to further refine the ore, ensuring complete liberation of mineral particles and providing conditions for subsequent flotation.
Stage 3 Grinding (Optional): For some complex ores or high-requirement concentrate products, stage 3 grinding can also be performed. This stage of grinding can achieve a grinding fineness of over 90% **-0.037mm**, suitable for beneficiation applications requiring extremely fine mineral liberation.
Controlling the grinding fineness is crucial for flotation efficiency. Excessively coarse grinding leads to insufficient liberation of iron minerals from gangue minerals, affecting the concentrate recovery rate in subsequent flotation; while excessively fine grinding increases energy consumption and may cause over-refinement of the pulp, affecting pulp flowability and foam stability during flotation. Therefore, precise control of the grinding fineness is essential during staged grinding.
2. Weak Magnetic Separation
Process Description: The ground pulp enters a weak magnetic separator. Based on the magnetic characteristics of iron minerals, the separator adsorbs magnetic minerals onto the magnetic separator drum, while non-magnetic gangue minerals are discharged with the pulp. The purpose of this step is to initially remove gangue minerals, preparing for the subsequent reverse flotation process.
Product: The magnetic concentrate separated by magnetic separation enters the reverse flotation operation, while the unqualified pulp is sent to waste rock treatment.
3. Reverse Flotation
Technical Principle: Utilizing either cationic or anionic reverse flotation technology, gangue minerals are separated from iron minerals through a single roughing and cleaning process. Collectors and frothers are added during flotation; gangue minerals enter the flotation froth, while iron minerals remain in the pulp as concentrate.
Flotation Reagents: Depending on the ore properties, either cationic or anionic collectors can be used. Cationic collectors are typically used for ores rich in silicate minerals, while anionic collectors are suitable for more complex ores.
Results: The final product of reverse flotation is a high-grade iron concentrate, with an iron concentrate grade that can be increased to approximately 69%, while controlling the SiO₂ content below 4%. The iron content of the flotation tailings is typically 10%–12%.
4. Flotation Froth Treatment and Regrinding
Regrinding Process: After concentration, the flotation froth enters the regrinding stage. The grinding fineness is typically controlled to **over 90% of particles being -0.037 mm**, ensuring that the mineral particles are finely refined to the standard of complete liberation.
Dewatering and Scavenging: The regrinded slurry is treated in a dewatering tank, then undergoes multiple scavenging magnetic separation processes to further recover iron minerals. The scavenged concentrate is returned to the reverse flotation system for further separation.
5. Multiple Scavenging and Tailings Disposal
Process Description: The multiple scavenging process aims to further purify magnetic minerals through multi-stage magnetic separation, ultimately controlling the iron content in the tailings to approximately 10%–12%.
Product Processing: The scavenged concentrate is returned to the reverse flotation process for further refining, ensuring maximum iron mineral recovery. The tailings are discharged into a tailings pond for treatment.
Process Description
In this dataset, the iron concentrate has a grade of 69%, belongs to transition metals, and is the primary product of the mineral processing stage. Iron concentrate is typically in powder form and is widely used in downstream processing technologies at sintering 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
Technical principle of staged grinding, low-intensity magnetic separation-reverse flotation technology: cationic reverse flotation or anionic reverse flotation technology is adopted, and the final concentrate is obtained after one rougher and one cleaner flotation. The reverse flotation froth is concentrated and magnetically separated, then re-ground; the re-ground product is de-slurried and subjected to multiple scavenging magnetic separations for tailings disposal, while the magnetic concentrate is returned to the reverse flotation operation for further processing. Technology applicability and characteristics: The staged grinding, low-intensity magnetic separation-reverse flotation technology can improve metal recovery rates, relatively reduce mining volume, and reduce pollution at the source. Using this technology, the iron concentrate grade can reach nearly 69%, with SiO2 content reduced below 4%, and flotation tailings containing 10%-12% iron. This technology is suitable for magnetite with high impurity content or when high-quality iron concentrate is required.