As an important source of metal resources, lead and zinc ores have economic and industrial values. With the continuous expansion of the use of lead and zinc ores, the development and utilization of lead and zinc ores are increasingly valued. The beneficiation process of lead-zinc ore can be divided into four stages: crushing and grinding stage, separation stage, product dehydration stage and tailings treatment stage. In this paper, we will start from the perspective of lead-zinc ore beneficiation process flow, and make an inventory of all kinds of beneficiation equipment used in lead-zinc ore beneficiation process flow.
The crushing and grinding stage of lead-zinc ore can be divided into two parts: crushing screening and grinding classification. This stage determines the particle size of the selected materials of lead-zinc ore and relates to whether the subsequent beneficiation of lead-zinc ore can be carried out smoothly.
In the crushing process of lead-zinc ore, according to the different technological processes, the crushing processes adopted include one stage crushing and screening, two stage one closed circuit crushing and screening, etc. Jaw crusher can be used for coarse crushing in the crushing stage, cone crusher can be used for medium crushing, and circular vibrating screen can be used for screening equipment.
Some lead-zinc ores are easy to produce slime, which may have an impact on the beneficiation stage. According to the different properties of lead-zinc ores, ore washing and desliming can be added in the crushing and screening, ore washing screens can be used for ore washing equipment, and spiral graders can be used for desliming equipment.
In the process of grinding and classification of lead and zinc ores, one stage closed circuit grinding and classification system and two stage closed circuit grinding and classification system can be used. According to different particle size composition of lead and zinc ores, the process of stage grinding and stage separation can also be used. The ball mill is the main grinding equipment, and the hydrocyclone is the classification equipment.
The beneficiation of lead-zinc ore is generally based on flotation process, which includes the preferential flotation process of flotation of lead followed by flotation of zinc, the mixed flotation process of mixed flotation of lead and zinc followed by separation, the floatable flotation process of flotation of easy to float lead and zinc followed by flotation of difficult to float lead and zinc, the gravity flotation combined process, the flotation magnetic combined process, etc.
For the selection of flotation equipment, various types of suction mechanical stirring flotation machines (SF flotation machine, BF flotation machine, JJF flotation machine) and aerated mechanical stirring flotation machines (KYF flotation machine, XCF flotation machine) can be used. The combined unit composed of KYF flotation machine and XCF flotation machine can be considered. Among them, XCF is used as suction tank and KYF is used as DC tank to achieve horizontal configuration without foam pump.
Gravity separation and magnetic separation can be added to the beneficiation process according to the beneficiation index of specific ores as supplementary processes to improve the beneficiation index. Among them, shaking table is generally used for gravity separation, and permanent magnetic cylinder type magnetic separator is generally used for magnetic separation.
The filtration dehydration stage of lead-zinc ore includes dehydration and filtration, which determines whether the use demand of lead-zinc concentrate can be met. In the dewatering stage, high-efficiency thickener is generally used to dewater different kinds of concentrates.
In the filtration stage, the dewatered concentrate can be further treated with programmable hydraulic chamber filter press, ceramic vacuum filter, disc vacuum filter and other equipment to make it more in line with the product water content requirements.
Tailings produced in the beneficiation process of lead and zinc ores are generally temporarily stacked by dry discharge of tailings, which not only relieves the pressure of tailings pond capacity, but also reduces the potential safety hazards of tailings pond, and the utilization of backwater reduces the pressure of sewage treatment, saves the cost of mine production and operation, which is also the requirement of national green and environmental mine construction.
Taking the common dry discharge process scheme of lead-zinc mine tailings - the dehydration process of hydrocyclone+dewatering screen+filter press as an example, this process takes the hydrocyclone, dewatering screen and filter press as the main equipment. Tailings are transported to the rubber pump box by gravity or pump, and pumped into the concentrated hydrocyclone group. The underflow of the hydrocyclone flows automatically to the dewatering screen. The dewatering screen is transported out of the workshop for storage by belt, and the screen is transported to the thickener by pump. The overflow of the cyclone flows to the thickener automatically. After being concentrated, it is pumped into the filter press by the feed pump of the filter press to form filter cake, which is transported out of the workshop for storage with a belt. The filtrate of the filter press and the filtrate of the dewatering screen flows automatically to the filtrate buffer pool, and then is pumped to the thickener. The overflow of the thickener flows automatically to the return pool, and after being clarified, it is pumped back to the concentrator for use.
The above are common lead-zinc ore dressing process equipment. In the actual concentrator, the properties of lead and zinc ores are complex and diverse. The selection of beneficiation equipment and process flow of lead and zinc ores should follow scientific and reasonable basis. Therefore, it is suggested that the beneficiation test should be carried out first. Through the analysis of beneficiation test, suitable beneficiation equipment and beneficiation process of lead and zinc ores should be customized to achieve ideal return on investment.
