The raw ore of this project contained 3.68% of lead, 2.85% of lead in lead oxide, and 77.45% of lead oxidation; 16.06% of zinc, 15.93% of zinc in zinc oxide, and 99.20% of zinc oxidation. It can be seen that the raw ore was a refractory polymetallic ore. The main metal minerals were galena, white lead, sphalerite, hemimorphite, siderite, pyrite, limonite, hematite, and silverite. The main non-metallic minerals were quartz, feldspar, hornblende, chlorite, calcite, mica and some clay minerals.
Crushing and screening stage: two stage and one closed circuit crushing and screening process was adopted. The raw ore was transported to the raw ore bin of the dressing plant by truck. A fixed grid screen was set on the top of the bin. The large pieces of ore on the screen were crushed manually. The qualified ores under the screen were sent to the jaw crusher for coarse crushing by the electric vibrating feeder. The coarse crushing products were sent to the double-layer circular vibrating screen by No.1 belt conveyor for screening. The upper screen opening of the circular vibrating screen was 20 mm and the lower screen hole was 10 mm. The products on the screen would flow to No.2 belt conveyor for fine crushing, and the fine crushing products would be sent to No.1 belt conveyor to round vibrating screen for screening again. The fine materials under the screen were washed by washing water to the classifier for a stage of ore washing operation, and the overflow was pumped to the ore washing overflow buffer tank beside the powder ore bin by Xinhai wear-resistant rubber pump, and the ore washing return sand and the intermediate products of the vibrating screen were transported to the powder ore bin by No.3 large angle belt conveyor.
Grinding and beneficiation stage: two stage and one closed circuit grinding + lead flotation (two roughing, one scavenging and four cleaning) + zinc flotation (two roughing, two scavenging and four cleaning) process flow was adopted. A tilting feeder was set at the bottom of the round powder ore bin. The fine ore was sent to a wet grid type ball mill through No.4 belt conveyor for grinding, and the ball mill was equipped with Xinhai wear-resistant cyclone for classification. The return sand of hydrocyclone returned to the ball mill, while the overflow was sent to the secondary cyclone group for classification. The grit of the cyclone group was returned to the secondary overflow ball mill for grinding, and the overflow entered the high-efficiency stirring tank before flotation. The feeding of two-stage classification hydrocyclone was completed by Xinhai wear-resistant rubber pump. The pulp entered the lead flotation system after being fully medicated. Two roughing, one scavenging and four cleaning processes were adopted for lead flotation. SF-4 flotation machine was used for I and II scavenging, SF-2 flotation machine used for cleaning I and II, and SF-2 flotation machine used for III and IV cleaning. The lead concentrate was pumped from a slurry pump to a high-efficiency thickener. The lead tailings were pumped from a vertical slurry pump to a ceramic filter for stage dewatering. The filtrate was pumped by a clean water pump to a φ10m lead flotation supply tank, and the filter cake entered the high-efficiency stirring tank for slurry mixing and chemical treatment, then entered the next high-efficiency stirring tank for further chemical treatment, and then entered the zinc flotation system. Two roughing, two scavenging and four cleaning processes were adopted for zinc flotation. SF-4 flotation machine was used for roughing I, II and scavenging I and scavenging II. SF-2.8 flotation machine was selected for cleaning I, cleaning II and III and cleaning IV. Zinc concentrate was pumped from Xinhai wear-resistant rubber pump to high-efficiency thickener, and zinc tailings were pumped from Xinhai wear-resistant rubber pump to high-efficiency transformed thickener.
Concentrate dehydration stage: lead and zinc concentrate were dehydrated by means of mechanical dehydration. After being thickened by high-efficiency transformed thickener, the lead concentrate flowed into the disc filter for filtration, which was then transported to the lead concentrate storage yard by a NO.5 belt conveyor, and the filtrate was pumped to the high-efficiency transformed thickener. After the zinc concentrate thickening through the high-efficiency transformed thickener, the gravity flow entered the disc filter for filtration, and the filter was transported to the zinc concentrate storage yard by a No.5 belt conveyor, and the filtrate was driven to the high-efficiency transformed thickener.
Tailings dehydration stage: mechanical dehydration was adopted. After the tailings were thickened by the high-efficiency reformed thickener, the self-flow entered the disc filter for filtration, which was then transported to the tailings yard by two NO.5 belt conveyors. The filtrate was pumped from 40PV-SP to the high-efficiency reformed thickener. The overflow of the thickener was all collected into the overflow water settling tank, and after settling and clarifying, which was pumped by the clean water pump to the zinc flotation supply tank.
The processing capacity of this project was 500t/d, and the final products were lead concentrate and zinc concentrate. The grade of lead concentrate and zinc concentrate was 41.03% and 42.85% respectively.