Lead and zinc tailings utilization examples

1. Recovery of silver from lead-zinc tailings

Tailings stock pile Bajiazi lead zinc ore 3,000,000 t, with higher silver content, of 69.94g / t, which is then ground to -0.053mm91.6% dissociation of silver, with sodium carbonate as modifier ( 3000g/t), butyl ammonium black drug (53g/t) and butyl xanthate (63g/t) as collector , No. 2 oil (8g/t) as foaming agent, silicone rubber (100g/t) for inhibition The agent is flotation of silver-containing concentrate with a grade of 1193.85g/t and a recovery rate of 63.74%. According to the tailings treatment capacity of 800t / d, the annual production days of 250 days, the annual recovery of silver 8.92t, the output value of about 2.23 million yuan.

2. Recovery of tungsten from lead-zinc tailings

The Baoshan lead-zinc-silver mine is a comprehensive deposit, and the ore processed by the concentrator comes from the primary ore body and the weathered ore body. The ore is mainly useful minerals brass ore, molybdenite, galena, sphalerite, bismuthinite, pyrite, scheelite, wolframite; major gangue minerals Grossular, Calcium iron garnet, quartz , calcite , pyroxene, amphibole, kaolin and the like. The plant's sulfide ore flotation tailings contain low-grade tungsten minerals, mainly scheelite. The tailings after primary ore flotation of lead and zinc contain 0.127% of WO3, of which scheelite accounts for 81%, black tungsten ore accounts for 16%, and tungsten carbide accounts for 3%. The grain size of scheelite is 80% concentrated in -0.074 mm + 0.037 mm; the grain size of the wolframite is 65% concentrated in -0.037 mm + 0.019 mm. The main mineral content and particle size composition of the primary ore flotation tailings are shown in Table 1 and Table 2, respectively.

Table 1 Main mineral content of primary ore flotation tailings (%)

Table 2 primary ore flotation tailings composition and size distribution of metal

The properties of weathered ore flotation tailings are similar to those of primary ore. The WO ₃ content is 0.134%, but the content of black tungsten ore is slightly higher than that of primary ore, accounting for about 25%. The scheelite has a finer particle size, and most of it is concentrated between -0.074mm + 0.019mm. The gangue minerals are mainly composed of feldspar and have many feldspars and iron minerals.

Experimental studies have shown that the use of cyclones, spiral chutes and shakers to enrich tungsten minerals in flotation tailings can reduce the consumption of white tungsten flotation reagents and early recovery of wolframite. That is, the tailings are firstly sorted by a short cone hydrocyclone and then the spiral chute is used to select the coarse concentrate. The coarse concentrate is selected from the wolframite and then floated to the scheelite. See Figure 1 for the WO ₃ content. 47.29%～50.56%, the recovery rate is 18.62%～20.18% concentrate, and the crude concentrate with the yield of 26.95%～34.027% needs to be further floated by white tungsten, compared with single flotation The amount of white tungsten selected is reduced by 73.05% to 65.97%, which can save a lot of dosage and reduce the cost of mineral processing.

Figure 1 Test procedure

Hunan Shaodong Lead-Zinc Mine is a mine with a daily ore selection of more than 200 tons of ore. The deposit is a medium-low temperature hydrothermal fissure fluorite -quartz vein type lead-zinc polymetallic deposit. Is selected from mineral processing plant using two metal recovery of lead and zinc flotation of lead and zinc in an amount of from 6.0 to tailings discharge 63000 t, tailings simple mineral composition, mainly quartz, slate dust, fluorite, calcite small amount , feldspar, barite , muscovite, etc., the main mineral quartz, slate shavings, fluorite content of about 90%, the main element content and mineral composition of tailings are shown in Table 3, Table 4.

Table 3 Main element content of tailings (%)

Table 4 Mineral composition and content of tailings (%)

The Changsha Nonferrous Metal Research Institute conducted research on the use of tailings after lead and zinc sorting. According to the nature of the raw materials, the fluorite was recovered by a branch flotation process (see Figure 2). The test results show that the obtained fluorite concentrate grade is CaF _{2 .} The annual recovery of fluorite is more than 4,500 tons and the profit is more than 600,000 yuan.

Figure 2 Branch flotation process

Gaoqiao Lead-Zinc Mine is a small-scale non-ferrous enterprise supported by China Nonferrous Metals Industry Corporation. The mine has been rebuilt and expanded. At present, the capacity of daily lead or zinc ore is 200t. It is a medium-temperature hydrothermal filling sulfide deposit and is now recycled. Lead and zinc are the main metals, with an annual output of about 60,000 tons of tailings. The content of barite in the tailings was 7.4%, and the basic monomer was dissociated. The plant adopts heavy and floating processes to re-select the tailings and recover the barite. At the same time, lead and zinc are also obviously enriched in the barite concentrate. Therefore, through secondary recovery, the purpose of comprehensive utilization of resources is achieved.

The production process for recycling barite is shown in Figure 3. By re-selecting the Gaoqiao lead-zinc mine, the barite concentrate can be obtained from the tailings sand by about 3000t per year, the annual profit is about 300,000 yuan, and the recovered barite concentrate contains 97.8% BaSO ₄ , which is in line with the rubber filler class II product. Claim. At present, barite is mainly used as a mud weighting agent for oil drilling. It can also be used as a raw material for zinc bismuth in rubber and paint, as well as raw materials for the production of metal bismuth and various strontium salts. The production and sales prospects are optimistic.

Figure 3 Barite recycling production process

The Chaihe lead-zinc mine has stored millions of tons of tailings. The mine first re-selected the tailings with a screw-slot chute, and then heavy sand was used for flotation treatment to obtain qualified zinc, lead and sulfur concentrates. Silver is recycled comprehensively. According to the annual treatment of 850,000 tons of tailings, the flotation of re-election concentrate is 150,000 tons, and the annual recovery of lead concentrate is 46% of lead concentrate 1890t, sulfur-containing 35% sulfur concentrate 10542t, zinc containing 45% The zinc sulfide concentrate is 5,840 tons, and the zinc oxide concentrate containing 35% zinc is 18,991 tons. In addition, lead concentrate contains 3212kg of silver. The total output value is 12.27 million yuan (excluding the value of sulfur concentrate), and the profit is 3.3 million yuan.

In foreign countries, the zinc flotation tailings of the Belousov lead-zinc plant in Russia contain zinc, lead, copper, iron sulfides and barites, which are re-selected by flotation to produce sulfides containing copper, zinc and lead. Mixed concentrate; pyrite concentrate containing 39% to 40% of iron, recovery rate of 87.8%, and barite concentrate containing BaSO ₄ 88% to 90% and recovery rate of 48.2% to 61.6%.

A number of lead-zinc flotation tailings in Guangdong Yuexi and Yuebei areas were re-elected to recover pyrite in tailings by spiral chute. The mineral composition of the lead-zinc flotation tailings in Yuebei and Yuexi, the single mineral analysis of pyrite , the multiple analysis of lead and zinc tailings, and the screening analysis are shown in Tables 5 to 8.

Table 5 Mineral composition

Table 6 Analysis of single minerals of sulfur-iron and sulfur in northern Guangdong (%)

Table 7 Multiple analysis of lead and zinc tailings in Yuebei (%)

Table 8 Screening analysis results (%)

In the test, the lead-zinc tailings were sorted by a spiral chute (see Figure 4) to obtain a pyrite concentrate with a grade of 39.75% to 44.08% and a recovery rate of 58% to 74%.

Figure 4 Test process of Yuebei lead-zinc tailings

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