As the core link of modern mineral processing system, the technology
selection of sorting process directly affects the comprehensive
utilization efficiency of mineral resources. In the context of the
increasing depletion of mineral resources, how to achieve efficient
separation of ores through scientific sorting methods has become
the key to improve the metal recovery rate and production efficiency.
First, the technical principle of ore sorting
Ore sorting is established on the basis of the differences in the physical
and chemical properties of minerals, and the selective separation of
target minerals is realized through precise technical means. Sorting
efficiency depends on the precise control of the characteristics of the
ore, where the density difference directly affects the gravity sorting
effect, magnetic difference determines the selection parameters of
magnetic separation equipment, conductivity difference is related to
the success rate of electrostatic sorting. Modern sorting process
through the multi-parameter joint analysis system, the ore samples
can be particle size distribution detection, surface potential
measurement, magnetization rate test and other 17 key indicators
testing, to provide data support for process selection.
Particle size control is the basic element of sorting process design,
different particle size range of ore needs to match the corresponding
sorting equipment. For 0.1-5mm fine-grained ores, spiral separator
or shaking table is mostly used for sorting; micro-fine-grained
(<0.074mm) materials need to use centrifugal sorting or flotation
process. The influence of shape coefficient on the sorting effect is
also significant, the trajectory of flake minerals in the airflow
sorting and equiaxial minerals there are obvious differences in
this feature is often used in the sorting of mica minerals.
Second, the mainstream sorting technology
analysis
Gravity separation technology through the construction of artificial
gravity field to realize the separation of minerals, typical equipment
including jig machine (processing size 2-30mm), spiral chute
(processing size 0.02-2mm) and centrifugal concentrator (processing
size 0.01-0.1mm). An iron ore mine has improved concentrate grade
by 12% and recovery by 9.8% by using a multi-stage spiral chute
combination process. The technology has significant sorting effect
on mineral system with density difference >0.5g/cm³, and the unit
energy consumption is 35% lower than the traditional process.
Magnetic separation technology has made breakthrough progress
in recent years, superconducting magnetic separator background
magnetic field strength of up to 5T or more, the recovery of weakly
magnetic minerals to enhance the ability of significant. High-voltage
electrowinning equipment has exceeded 60kV working voltage, in
titanium zirconium ore sorting, electrowinning concentrate TiO₂
ontent can reach more than 95%. Compound force field sorting
equipment couples magnetic force, electric force and gravity field,
showing unique advantages in dealing with complex symbiotic
ores, and a polymetallic mine adopts this technology to increase
the comprehensive recovery rate by 18.6%.
Flotation technology realizes selective separation by regulating
the surface properties of minerals through chemicals, and the
development of new types of collectors makes the recovery of
micro-fine-grained minerals possible. The application of column
flotation machine increases the flotation efficiency by 30%,
while the bubble mineralization rate of inflatable flotation machine
can reach more than 85% when dealing with difficult-to-select ores.
Photoelectric sorting technology adopts CCD spectral analysis
system, the recognition accuracy reaches 0.1mm level, and 99.2%
recognition accuracy is realized in diamond sorting.
Third, sorting process optimization strategy
Ore characteristics analysis is the basis of process optimization, it is
recommended to establish a three-dimensional mineral model to
simulate the sorting test. Through X-ray diffraction, scanning
electron microscopy and other analytical means, the mineral embedded
characteristics can be accurately determined, a copper mine through
the mineral dissociation analysis to optimize the grinding fineness
to -200 mesh accounted for 78% of the sorting efficiency by 22%.
The optimization of process parameters requires the establishment
of a dynamic response model, a gold mine through the response
surface method optimization to reduce the amount of sodium
cyanide by 15%, leaching rate increased by 3.2%.
Equipment selection needs to consider the balance between
processing capacity and operating costs, and it is recommended
to use modular design to realize flexible production. A plant
extends the applicable mineral types to 5 categories by configuring
the magnetic separator with adjustable magnetic system structure.
Intelligent control system can adjust the sorting parameters in
real time. After the introduction of DCS system in an iron ore
sorting workshop, the fluctuation range of concentrate grade
was reduced from ±1.5% to ±0.3%.
The innovative direction of sorting technology is developing in the
direction of refinement and intelligence. The application of quantum
sensing technology improves the accuracy of mineral property detection
by two orders of magnitude, and the introduction of 5G technology
realizes the remote real-time control of sorting equipment. The future
sorting process will pay more attention to environmental friendliness,
and green technologies such as biological sorting and ultrasonic-assisted
sorting will be gradually industrialized. Under the general trend of
comprehensive utilization of resources, the progress of sorting process
will continue to promote the development of mineral resources in the
direction of high efficiency and cleanliness.