Method for improving tin recovery rate in pyrogenic process lead smelting process

Abstract

The invention discloses a method for improving the tin recovery rate in the pyrogenic process lead smelting process, and relates to the field of non-ferrous metal smelting. According to the method, copper-containing materials and lead concentrate are mixed according to a certain proportion, and copper dross with the high tin content is produced after the steps of burdening, bottom blowing smelting, reduction smelting, pyrogenic process refining for removing copper and tin and the like. According to the method, the copper element is introduced in the pyrogenic process lead smelting process, efficient enrichment of the tin element in the lead concentrate in the copper dross is achieved, the recovery rate and the enrichment rate of tin in the pyrogenic process lead smelting process are increased, the produced copper dross with the high tin content can serve as a raw material for further recovery of tin, and the method is easy to operate and has good economic benefits.

Description

Technical Field

[0001] The invention belongs to the field of nonferrous metal smelting, and in particular relates to a method for improving the tin recovery rate in the process of pyrometallurgical lead smelting. Background Art

[0002] Tin is one of the earliest metals discovered and used by humans. Since the 20th century, with the development of the electronics industry, tin has gradually become an important metal material that is indispensable to modern industry. However, after long-term mining, tin ore resources have gradually been exhausted, and the separation of tin from tin-associated ores has become a research hotspot today.

[0003] Lead and tin have similar physical and chemical properties. They are both IVA group elements in the periodic table. These two elements usually coexist with each other, but the tin content of lead concentrate is relatively low. Most domestic lead smelters do not recycle tin. Since tin metal is easily oxidized and easily forms alloys with other metals, it is dispersed in the lead smelting production process. It is distributed in crude lead, copper slag, electrolyte, lead anode mud, water quenching slag, etc., and tin is difficult to be recovered in a centralized manner. At present, the research hotspots in China are mainly focused on the enrichment and recovery of tin from reverberatory furnace crude lead. Only a few lead smelters in China enrich and recover tin in the form of tin-rich slag during the pyrometallurgical refining of reverberatory furnace crude lead. There are problems such as low tin recovery rate and easy dispersion of tin in the lead smelting process.

[0004] Therefore, the efficient recovery of tin metal in the lead smelting production process is a technical challenge in the industry. At the same time, with the rapid development of my country's lead smelting industry, the crude lead production capacity of large domestic lead smelters has reached 100,000 tons or more. Recovering metallic tin from the lead smelting process and improving the tin recovery rate has great economic value and significance. Summary of the invention

[0005] Based on the problems existing in the background technology, the present invention overcomes the shortcomings of the prior art and provides a method for improving the tin recovery rate in the pyrometallurgical lead smelting process. By mixing a certain ratio of copper-containing materials with lead concentrate, after batching, bottom blowing smelting, reduction smelting, pyrometallurgical refining and copper and tin removal steps, a copper slag with a high tin content is produced, so as to achieve the purpose of enriching most of the tin in the lead concentrate in the copper slag and improving the tin recovery rate in the lead concentrate. The present invention is achieved by the following technical solutions:

[0006] A method for improving the tin recovery rate in the pyrometallurgical lead smelting process, the specific steps of which are as follows:

[0007] (1) First, lead concentrate, copper-containing materials, fly ash, limestone, quartz sand, lump coal and other materials are transported to the granulator through a feeding belt in a certain proportion for mixing and granulation to obtain pelletized ore;

[0008] (2) The evenly mixed pellets are transported to a bottom-blown smelting furnace through a feeding belt for smelting to produce high-lead slag;

[0009] (3) The high-lead slag is transported to the reduction furnace through a chute, and coke or charcoal is added for reduction smelting to produce crude lead;

[0010] (4) The crude lead produced by the reduction furnace is transferred to a lead melting pot for fire refining to remove copper and tin, producing high-tin copper slag.

[0011] Furthermore, the copper content of the pellets after mixing and granulation in step (1) is controlled to be 1.8-2.0%.

[0012] Furthermore, the copper-containing material in step (1) is copper sulfide concentrate, copper oxide concentrate, matte, etc. or a mixture thereof.

[0013] Furthermore, in step (1), the slag type is controlled as follows: m(Fe) / m(SiO 2 )=1.6~1.8, m(CaO) / m(SiO 2 )=0.3~0.6.

[0014] Furthermore, in the step (1), the copper-containing material is fed using a separate feeding belt, which facilitates timely adjustment of the furnace condition.

[0015] Furthermore, in step (2), the smelting temperature of the bottom blowing furnace is controlled at 1000-1100°C.

[0016] Furthermore, in step (3), the reduction smelting temperature is controlled at 1150-1250°C.

[0017] The main mechanism involved in the method for improving the tin recovery rate in the pyrometallurgical lead smelting process described in the present invention is:

[0018] In the crude lead production process, the copper content in the mixed ore is increased by adding a certain proportion of copper-containing materials to increase the copper content in the lead liquid. Copper has a strong affinity with elements such as arsenic, antimony, and tin, which can form Cu 3 As, Cu 5 As, Cu 2 Sb and Cu 6 Sn 5 The high melting point intermetallic compounds, and the binding energy of the intermetallic compounds is greater than the dissolution energy of arsenic, antimony, and tin in the lead liquid phase. In the process of crude lead pyrometallurgy, Cu 3 As, Cu 5 As, Cu 2 Sb and Cu 6 Sn 5High melting point intermetallic compounds such as tin and copper are precipitated from the lead liquid, and tin is enriched in the copper slag together with copper, arsenic, antimony and other elements, so as to achieve the purpose of efficient enrichment of tin in lead concentrate and improve the recovery rate.

[0019] The beneficial effects of the present invention are:

[0020] (1) This process is simple to operate. Without changing the main production process of crude lead, only the ingredients in the production process are optimized. The production process is easy to implement and the production cost is low.

[0021] (2) This process can achieve efficient enrichment and recovery of tin in lead concentrate. The recovery rate of tin in lead concentrate can be increased from 54% to more than 73%. Tin is mainly enriched in high-tin copper slag, and the tin content in high-tin copper slag can reach 1.28%;

[0022] (3) This process has a high level of resource utilization, and the high-tin copper slag produced can be used as raw material for further tin recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods.

[0025] Embodiment 1:

[0026] The lead concentrate, copper-containing materials, fly ash, limestone and quartz sand are mixed and granulated to obtain mixed pellets. The element analysis of the mixed pellets is as follows:

[0027]

[0028] The mixed pellets are added to the bottom blowing furnace through the feeding belt for smelting. During the smelting process, the pellet feeding rate is 48t / h, and the oxygen-to-material ratio is controlled at 115Nm 3 / t, the smelting temperature is controlled at 1000℃, the smelting time is controlled at 1.5h, and high-lead slag is released after the smelting is completed; the high-lead slag enters the reduction furnace through the chute for reduction smelting, the reduction smelting temperature is controlled at 1200℃, the amount of aromatic carbon added is controlled at 2t / h, the reduction smelting time is controlled at 2h, and the reduction slag and crude lead are released after the reduction smelting is completed; the crude lead in the reduction furnace is transported to the crude lead pyro-refining process for pyro-refining, the crude lead is first hoisted into the lead melting pot for melting, and then multiple The surface slag is removed by the secondary slag pressing and slag removal operations. When the lead liquid temperature drops to 500℃, it is hoisted into a mixer for stirring to form a vortex. Lead oxide slag is added to the vortex and stirred for 0.5h. The thin slag is removed. After the thin slag is removed, the residual anode is added for cooling. In order to speed up the operation, water is sprayed on the surface of the lead liquid to cool it down so that the lead liquid temperature is gradually reduced to 330℃. The solidified slag on the surface is removed. The high-tin copper slag obtained from the fire refining process can be used as a raw material for further recovery of tin.

[0029] After the above process, the tin content in crude lead, lead anode plate and high-tin copper slag is as follows:

[0030]

[0031] Embodiment 2:

[0032] The lead concentrate, copper-containing materials, fly ash, limestone and quartz sand are mixed and granulated to obtain mixed pellets. The element analysis of the mixed pellets is as follows:

[0033]

[0034] The mixed pellets are added to the bottom blowing furnace through the feeding belt for smelting. During the smelting process, the pellet feeding rate is 45t / h, and the oxygen-to-material ratio is controlled at 118Nm 3 / t, the smelting temperature is controlled at 1000℃, the smelting time is controlled at 1.5h, and high-lead slag is released after the smelting is completed; the high-lead slag enters the reduction furnace through the chute for reduction smelting, the reduction smelting temperature is controlled at 1250℃, the amount of aromatic carbon added is controlled at 1.8t / h, the reduction smelting time is controlled at 2h, and the reduction slag and crude lead are released after the reduction smelting is completed; the crude lead in the reduction furnace is transported to the crude lead pyro-refining process for pyro-refining, the crude lead is first hoisted into the lead melting pot for melting, and then melted. The surface slag is removed by repeated slag pressing and slag removal operations. When the lead liquid temperature drops to 480℃, it is hoisted into a mixer for stirring to form a vortex. Lead oxide slag is added to the vortex and stirred for 0.5h. The thin slag is removed. After the thin slag is removed, the residual anode is added for cooling. In order to speed up the operation, water is sprayed on the surface of the lead liquid to cool it down, so that the lead liquid temperature is gradually reduced to 340℃. The solidified slag on the surface is removed. The high-tin copper slag obtained from the pyro-refining process can be used as a raw material for further recovery of tin.

[0035] After the above process, the tin content in crude lead, lead anode plate and high-tin copper slag is as follows:

[0036]

[0037] Embodiment 3:

[0038] The lead concentrate, copper-containing materials, fly ash, limestone and quartz sand are mixed and granulated to obtain mixed pellets. The element analysis of the mixed pellets is as follows:

[0039]

[0040] The mixed pellets are added to the bottom blowing furnace through the feeding belt for smelting. During the smelting process, the pellet feeding rate is 50t / h, and the oxygen-to-material ratio is controlled at 118Nm 3 / t, the smelting temperature is controlled at 1050℃, the smelting time is controlled at 1.5h, and high-lead slag is released after the smelting is completed; the high-lead slag enters the reduction furnace through the chute for reduction smelting, the reduction smelting temperature is controlled at 1230℃, the amount of aromatic carbon added is controlled at 2.0t / h, the reduction smelting time is controlled at 2h, and the reduction slag and crude lead are released after the reduction smelting is completed; the crude lead in the reduction furnace is transported to the crude lead pyro-refining process for pyro-refining, the crude lead is first hoisted into the lead melting pot for melting, and then melted. The surface slag is removed by repeated slag pressing and slag removal operations. When the lead liquid temperature drops to 500℃, it is hoisted into a mixer for stirring to form a vortex. Lead oxide slag is added to the vortex and stirred for 0.5h. The thin slag is removed. After the thin slag is removed, the residual anode is added for cooling. In order to speed up the operation, water is sprayed on the surface of the lead liquid to cool it down so that the lead liquid temperature is gradually reduced to 335℃. The solidified slag on the surface is removed. The high-tin copper slag obtained from the pyro-refining process can be used as a raw material for further recovery of tin.

[0041] After the above process, the tin content in crude lead, lead anode plate and high-tin copper slag is as follows:

[0042] .

Claims

1. A method for improving the tin recovery rate in the pyrometallurgical lead smelting process, characterized in that: The specific steps are as follows: (1) First, lead concentrate, copper-containing materials, fly ash, limestone, quartz sand, and lump coal are transported to a granulator through a feeding belt in a certain proportion for mixing and granulation to obtain pelletized ore; (2) The evenly mixed pellets are transported to a bottom-blown smelting furnace through a feeding belt for smelting to produce high-lead slag; (3) The high-lead slag is transported to the reduction furnace through a chute, and coke or charcoal is added for reduction smelting to produce crude lead; (4) The crude lead produced by the reduction furnace is transferred to a lead melting pot for fire refining to remove copper and tin, producing high-tin copper slag.

2. The method for improving the tin recovery rate in the pyrometallurgical lead smelting process according to claim 1, characterized in that: The copper content of the pellets after mixing and granulation in the step (1) is controlled to be 1.8-2.0%.

3. The method for improving the tin recovery rate in the pyrometallurgical lead smelting process according to claim 1, characterized in that: The copper-containing material in step (1) is copper sulfide concentrate, copper oxide concentrate, matte or a mixture thereof.

4. The method for improving the tin recovery rate in the pyrometallurgical lead smelting process according to claim 1, characterized in that: In the step (1), the slag type is controlled as follows: m(Fe) / m(SiO2)=1.6-1.8, m(CaO) / m(SiO2)=0.3-0.

6.

5. The method for improving the tin recovery rate in the pyrometallurgical lead smelting process according to claim 1, characterized in that: In the step (1), the copper-containing material is fed by a separate feeding belt, which is convenient for timely adjustment of the furnace condition.

6. The method for improving the tin recovery rate in the pyrometallurgical lead smelting process according to claim 1, characterized in that: In the step (2), the smelting temperature of the bottom blowing furnace is controlled at 1000-1100°C.

7. The method for improving the tin recovery rate in the pyrometallurgical lead smelting process according to claim 1, characterized in that: In the step (3), the reduction smelting temperature is controlled at 1150-1250°C.

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