With the rapid development of the photovoltaic industry and the semiconductor sector, the demand for high-purity silicon materials is increasing. Color sorting technology, with its high-precision and high-efficiency separation capabilities, is quietly becoming a critical link in the quality upgrading of silicon materials. In the mining and processing of silica (quartz sand, silicon ore, pebbles, pegmatite-type quartz deposits, etc.), the advancement of sorting technology directly impacts the purity and economic value of the products. Traditional manual sorting and mechanical screening methods are not only inefficient but also fail to meet the stringent requirements of industries such as photovoltaics and electronics for high-purity silica.
Quartz sand possesses unique physical and chemical properties, making it suitable for manufacturing glass, refractory materials, ferrosilicon smelting, metallurgical fluxes, ceramics, and grinding materials. In the construction industry, its strong resistance to acids and media corrosion is utilized to produce acid-resistant concrete and mortar. As a core raw material for silicon production, quartz sand plays a crucial role in the manufacturing of silicon-based materials.
Currently, the purification of quartz sand is primarily achieved through magnetic separation and flotation methods. However, after these processes, numerous impurities remain, and apart from manual sorting, there is no effective method to remove them. Based on the color difference between pure quartz sand and impurities, photoelectric color sorting machines can be employed for separation. These machines feature simple detection methods, fast sorting speeds, high system integration, and low costs.
Optoelectronic color selection technology refers to the use of special recognition lenses to capture surface image element signals of materials, collect material transmittance signals, or measure material moisture and other component information using infrared, ultraviolet, and other methods. It is processed by a processor to achieve photoelectric signal conversion, and compared with standard signals to analyze the quality of materials. Then, actuators are used to remove inferior materials. It is a high-tech comprehensive technology that integrates light, electricity, gas, and machinery.
The cost of manual sorting is increasing, and the value difference between high-purity quartz sand and low purity quartz sand is very large. Whether from an economic or ecological perspective, the application of photoelectric color sorting machines is extremely advantageous and effective. Therefore, the study of quartz sand color selection technology has profound significance.
The color sorter is mainly composed of a feeding system, an optical detection system, a signal processing system, and a separation execution system. Its working principle is a high-tech equipment that uses optical detection technology to automatically sort out particles of different colors in granular materials based on the differences in their optical characteristics.
① The material enters the machine from the top hopper, and through the vibration of the vibrating feeder, the selected material falls down the chute.
② The material passes through the vibrator at the upper end of the chute and accelerates down the chute into the sorting box.
③ After entering the sorting box, it passes between the image processing sensor CCD and the background device. Under the action of the light source, the CCD receives the synthesized light signal from the selected material, causing the system to generate an output signal, which is amplified and processed before being transmitted to the FPGA+ARM processing system. Then, the control system sends instructions to drive the spray solenoid valve to operate, and the spray valve blows the particles of different colors into the defective tank of the discharge hopper and flows away.
④ The selected materials continue to fall into the finished product tank of the receiving hopper and flow out, thereby achieving the purpose of selection.
The technical barriers in the color sorter industry are relatively high, mainly reflected in the demand for multidisciplinary technologies such as optoelectronic imaging, high-speed sensor technology, image processing, and computer algorithms. This means that companies need to continuously invest in research and development resources in order to gain market competitiveness.
In the future, color sorting machines will become more intelligent and automated, with the ability to automatically learn and accurately identify material characteristics. To meet the increasingly diverse needs of customers, manufacturers have launched customized products and provided tailored solutions. Meanwhile, the green and environmentally friendly development of color sorting machines is also an important direction for the industry.