CN118854051A - A method for recovering tin, lead and zinc resources from low-grade tin ore by silicon reduction fluorination roasting method - Google Patents

Abstract

The present invention belongs to the technical field of secondary resource recycling, and relates to a method for recovering tin, lead and zinc resources in low-grade tin ore by silicon reduction fluorination roasting method, comprising: mixing the tin ore with silicon material, roasting, collecting smoke and condensing, and obtaining condensed smoke enriched with tin, lead and zinc. Compared with the prior art, the present invention makes full use of the characteristics of strong reducing property of silicon reducing agent, strong tin-fluorine binding ability and high calcium fluoride content in low-grade tin ore, and performs directional conversion of tin dioxide, lead oxide, zinc oxide and calcium fluoride phases, and then realizes efficient separation and recovery of tin, lead and zinc resources through volatilization enrichment.

Description

A method for recovering tin, lead and zinc resources from low-grade tin ore by silicon reduction fluorination roasting

Technical Field

The invention belongs to the technical field of secondary resource recycling and utilization, and relates to a method for recovering tin, lead and zinc resources in low-grade tin ore by a silicon reduction fluorination roasting method.

Background Art

Low-grade tin ore is a low-grade tin ore with a tin content of 0.7wt%-10wt% produced during the beneficiation process due to the limitations of the beneficiation technology itself, the fine particles of the cassiterite ore itself, and the interpenetration with other gangue or ores. Its main phase components are hematite, magnetite, calcium iron silicate, lead oxide, zinc oxide, tin dioxide, calcium fluoride, etc., which are secondary tin resources. Its effective recovery will contribute to the sustainable utilization of tin resources and alleviate the increasingly prominent contradiction between the rapid growth of tin resource demand and the serious shortage of reserves. At present, the recovery of tin resources in complex tin ore mainly includes two categories: pyrometallurgy and hydrometallurgy. The pyrometallurgy is mainly divided into four types: reduction roasting, chlorination roasting, fuming smelting, and sulfidation roasting. The mechanism of action of reduction roasting method for treating medium tin ore is to reduce the tin phase (SnO ₂ ) in the ore into stannous oxide (SnO) by precisely controlling the reducing atmosphere at high temperature, and to volatilize and remove the tin phase by utilizing the high vapor pressure of SnO at high temperature and recover it. The mechanism of action of chlorination roasting method for treating medium tin ore is to add chlorinating agent and reducing agent at a certain temperature, and the chlorinating agent decomposes at high temperature to produce strong oxidizing Cl ₂ , so that the tin phase in the ore is converted into SnCl ₄ , and the difference in the volatility characteristics of SnCl ₄ and other metal chlorides at high temperature is utilized to achieve effective separation of tin. The mechanism of action of the fuming smelting method for treating tin ore is to selectively sulfide the tin phase in the mineral into stannous sulfide (SnS) by adding sulfiding agents and reducing agents, and volatilize and recover the tin. At the same time, in addition to sulfidation and volatilization, the tin in the fuming smelting method will be reduced to metallic tin for recovery. In order to better separate tin and iron, fuming smelting also needs to add slag-making agents to reduce the iron phase in the tin ore to FeO and enter the slag to separate from the tin phase. The mechanism of action of the sulfidation roasting method for treating tin ore is similar to that of the reduction roasting method. By adding sulfiding agents and reducing agents, the tin phase in the mineral is selectively sulfided into stannous sulfide (SnS). The high vapor pressure of SnS at high temperature is used, and the difference in vapor pressure with other components in the mineral is large, so that the tin in the material is volatilized and removed. The reduction roasting method requires precise control of the reduction roasting atmosphere, which is difficult to operate in practice; chlorination roasting, sulfidation roasting and fuming smelting methods require additional addition of chlorinating agents and sulfiding agents, which increases the economic cost. Compared with the prior art, the reduction fluorination roasting method proposed in the present invention has more advantages. It makes full use of the calcium fluoride present in the raw materials, has less gas phase environmental pollution in the process, and has no strict requirements on the reaction atmosphere. This method can also recover lead and zinc resources to a certain extent, and has good application prospects.

Chinese patent application CN117625999A discloses a method for recovering arsenic and tin resources in high-arsenic low-grade tin ore by a continuous two-stage reduction roasting method, comprising: mixing a first reducing agent with a high-arsenic low-grade tin ore, performing a roasting once, arsenic is enriched in the smoke volatilized by the first roasting, and obtaining a roasting slag; then mixing a second reducing agent with the first roasting slag, performing a second roasting, and tin is enriched in the smoke volatilized by the second roasting. The two-stage reduction roasting method has many steps, and both stages require the use of a carbonaceous reducing agent, which increases the carbon emission of the entire reduction process and causes harm to the environment. This method has defects both in terms of operating procedures and economic applicability. At the same time, this method mainly utilizes the method of tin ore phase reduction sulfide volatilization to achieve the dissociation and recovery of tin, while the present invention mainly utilizes the calcium fluoride component in the tin ore to convert tin into stannous fluoride and tin fluoride for volatilization enrichment, which is significantly different from patent CN117625999A.

Summary of the invention

The purpose of the present invention is to provide a method for recovering tin, lead and zinc resources in low-grade tin ore by silicon reduction fluorination roasting method, which makes full use of the characteristics of strong reducing property of silicon reducing agent, strong tin-fluorine binding ability and high calcium fluoride content in low-grade tin ore, and carries out directional conversion of tin dioxide, lead oxide, zinc oxide and calcium fluoride phases, and then realizes efficient separation and recovery of tin, lead and zinc resources through volatilization enrichment.

The purpose of the present invention can be achieved by the following technical solutions:

A method for recovering tin, lead and zinc resources from low-grade tin ore by silicon reduction fluorination roasting method comprises: mixing the tin ore with silicon material, roasting, collecting and condensing smoke to obtain condensed smoke enriched with tin, lead and zinc.

Furthermore, in the tin ore, the tin content is 0.7-10wt%, the lead content is 0.5-13wt%, the zinc content is 0.4-10wt%, and the fluorine content is 1.2-12wt%;.

Furthermore, the silicon material is selected from at least one of elemental silicon, silicon carbide, silicon slag or photovoltaic silicon cutting waste.

Furthermore, the silicon material is a mixture of elemental silicon, silicon carbide, silicon slag and photovoltaic silicon cutting waste in a mass ratio of 1: (0.3-0.4): (0.1-0.2): (0.5-0.6).

Furthermore, the silicon content in the silicon slag or photovoltaic silicon cutting waste is not less than 90wt%.

Furthermore, the silicon material is used in an amount of 1-15 wt% of tin ore.

Furthermore, in the calcination, the calcination temperature is 900-1200° C. and the calcination time is 30-180 min.

Furthermore, the tin ore is ground to 20-300 meshes before mixing.

Furthermore, the silicon material is ground to 20-300 meshes before mixing.

Compared with the prior art, the present invention has the following characteristics:

1) The present invention makes full use of the strong reducing property of silicon reducing agent, strong tin-fluorine binding ability and high calcium fluoride content in low-grade tin ore, etc., to carry out directional transformation of tin dioxide, lead oxide, zinc oxide and calcium fluoride phases, and then realizes efficient separation and recovery of tin, lead and zinc resources through volatilization enrichment, with low gas phase environmental pollution and high simultaneous recovery rate of tin, lead and zinc;

2) The method of the present invention has a short process, low cost and good prospects for promotion and application;

3) Aiming at the defects of Chinese patent application CN117625999A, the present invention is optimized. First, the steps of the present invention are simple and can be completed in one step. The use of silicon as a reducing agent can promote the fluorination of calcium fluoride, so that the fluorination reaction that could not occur originally can be carried out. The use of silicon cutting waste as a reducing agent achieves the purpose of treating waste with waste, and there is no additional carbon emission, and the harm to the environment can also be reduced accordingly.

In summary, the present invention has obvious advantages in terms of operation steps, environmental friendliness and economic applicability, and has good prospects for promotion and application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a process flow chart of a method for recovering tin, lead and zinc resources from low-grade tin ore by a silicon reduction fluorination roasting method in the present invention.

DETAILED DESCRIPTION

The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

The specific process steps involved in the present invention are: grinding a silicon reducing agent (elemental silicon, silicon carbide, silicon slag, photovoltaic silicon cutting waste or a mixture of two, three or four of the above) and a low-grade tin ore to a certain particle size and uniformly mixing them in a certain proportion, and then sending them into a roasting furnace for reduction fluorination roasting, and controlling key parameters such as roasting temperature, roasting time, and the amount of silicon reducing agent added. During the process, the silicon reducing agent reacts with tin dioxide, lead oxide, zinc oxide and calcium fluoride in the low-grade tin ore to undergo reduction fluorination reaction, tin is converted into stannous fluoride, lead oxide is converted into elemental lead, and zinc oxide is converted into elemental zinc. The three products are volatilized and enriched to achieve efficient separation and recovery of tin, lead and zinc resources in the low-grade tin ore, and the flue gas generated in the process is discharged into the atmosphere after waste heat recovery and flue gas treatment meet the standards. The present invention makes full use of the strong reducing property of silicon reducing agent, strong tin-fluorine binding ability and high calcium fluoride content in low-grade tin ore, etc., to carry out targeted transformation of tin dioxide, lead oxide, zinc oxide and calcium fluoride phases, and then realizes efficient separation and recovery of tin, lead and zinc resources through volatilization enrichment. It has the advantages of short process, low cost and good prospects for promotion and application.

This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

In the following examples, unless otherwise specified, raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.

Embodiment 1:

In conjunction with Figure 1, the method for recovering tin, lead and zinc resources from low-grade tin ore by silicon reduction fluorination roasting method, the specific implementation process of the case is as follows:

The low-grade tin ore of a certain ore dressing plant was taken as the treatment object, and its tin content was 3.24wt%, lead content was 2.01wt%, zinc content was 4.12wt%, iron content was 18.54wt%, calcium content was 24.83wt%, silicon content was 10.08wt%, fluorine content was 9.23wt%, and oxygen content was 25.48wt%;

Firstly, the low-grade tin ore and photovoltaic silicon cutting waste are respectively ground to 200 mesh and mixed evenly. The amount of photovoltaic silicon cutting waste added is 5wt% of the low-grade tin ore. Then, they are added into the roasting furnace kiln for reduction fluorination roasting. The roasting temperature is controlled at 900°C and the roasting time is 120 minutes. The tin, lead and zinc smoke volatilized during the roasting process is condensed through a condensation tower, and then collected and recovered through a dust collecting device. The roasting slag is discharged from the kiln head of the rotary kiln.

Atomic absorption spectrometry was performed on the roasting slag and volatile smoke, and it was found that the tin content in the roasting slag could be reduced to 0.09wt%, the lead content could be reduced to 0.08wt%, and the zinc content could be reduced to 0.11wt%; the tin content in the smoke was 18.90wt%, the lead content was 11.64wt%, and the zinc content was 18.41wt%. That is, the silicon reduction fluorination roasting achieved efficient recovery of tin, lead, and zinc in low-grade tin ore.

Embodiment 2:

In conjunction with Figure 1, the method for recovering tin, lead and zinc resources from low-grade tin ore by silicon reduction fluorination roasting method, the specific implementation process of the case is as follows:

The low-grade tin ore of a certain ore dressing plant was taken as the treatment object, and its tin content was 10wt%, lead content was 0.5wt%, zinc content was 0.4wt%, iron content was 10.62wt%, calcium content was 21.65wt%, silicon content was 19.36wt%, oxygen content was 22.01wt%, and fluorine content was 12wt%;

Firstly, the low-grade tin ore and elemental silicon are ground to 100 mesh respectively and mixed evenly, the elemental silicon is added in an amount of 8wt% of the low-grade tin ore, and then added into the fluidized bed of the roasting furnace for reduction fluorination roasting, the roasting temperature is controlled at 1200°C and the roasting time is controlled at 30 minutes, the tin, lead and zinc smoke volatilized during the roasting process is condensed in a condensing tower, and then collected and recovered by a dust collecting device, and the roasting slag is continuously discharged.

The roasting slag and volatile smoke were tested and analyzed, and it was found that the tin content in the roasting slag could be reduced to 0.02wt%, the lead content could be reduced to 0.01wt%, and the zinc content could be reduced to 0.06wt%; the tin content in the smoke was 45wt%, the lead content was 2.2wt%, and the zinc content was 1.8wt%. That is, the silicon reduction fluorination roasting achieved efficient recovery of tin, lead, and zinc in low-grade tin ore.

Embodiment 3:

In conjunction with Figure 1, the method for recovering tin, lead and zinc resources from low-grade tin ore by silicon reduction fluorination roasting method, the specific implementation process of the case is as follows:

The low-grade tin ore of a certain ore dressing plant was taken as the treatment object, and its tin content was 9.3wt%, lead content was 13wt%, zinc content was 10wt%, iron content was 15.62wt%, calcium content was 8.65wt%, silicon content was 6.36wt%, oxygen content was 22.01wt%, and fluorine content was 10wt%;

Firstly, low-grade tin ore and a mixture of elemental silicon, silicon carbide, silicon slag and photovoltaic silicon cutting waste (mixing mass ratio is 1:1:1:1) are respectively ground to 20 mesh and mixed evenly. The silicon mixture is added in an amount of 15wt% of the low-grade tin ore. Then, the mixture is added into a fluidized bed of a roasting furnace for reduction fluorination roasting. The roasting temperature is controlled at 1100°C and the roasting time is controlled at 180 minutes. The tin, lead and zinc smoke volatilized during the roasting process is condensed in a condensing tower and then collected and recovered by a dust collecting device. The roasting slag is continuously discharged.

The roasting slag and volatile smoke were tested and analyzed, and it was found that the tin content in the roasting slag could be reduced to 0.22wt%, the lead content could be reduced to 0.21wt%, and the zinc content could be reduced to 0.32wt%; the tin content in the smoke was 22wt%, the lead content was 34wt%, and the zinc content was 25wt%. That is, the silicon reduction fluorination roasting achieved efficient recovery of tin, lead, and zinc in low-grade tin ore.

The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims (8)

1. A method for recovering tin, lead and zinc resources in low-grade tin middlings by a silicon reduction fluorination roasting method is characterized by comprising the following steps: mixing the tin middlings with a silicon material, roasting, collecting smoke dust, and condensing to obtain condensed smoke dust enriched with tin, lead and zinc;

In the tin middling, the content of tin is 0.7-10wt%, the content of lead is 0.5-13wt%, the content of zinc is 0.4-10wt%, and the content of fluorine is 1.2-12wt%.

2. The method for recovering tin, lead and zinc resources in low-grade tin middlings by using a silicon reduction fluorination roasting method according to claim 1, wherein the silicon material is at least one selected from elemental silicon, silicon carbide, silicon slag and photovoltaic silicon cutting waste.

3. The method for recovering tin, lead and zinc resources in low-grade tin middlings by using the silicon reduction fluorination roasting method as claimed in claim 2, wherein the silicon material is simple substance silicon, silicon carbide, silicon slag and photovoltaic silicon cutting waste in a mass ratio of 1: (0.3-0.4): (0.1-0.2): (0.5-0.6).

4. The method for recovering tin, lead and zinc resources in low-grade tin middlings by a silicon reduction fluorination roasting method according to claim 2, wherein the silicon content in the silicon slag or the photovoltaic silicon cutting waste is not less than 90wt%.

5. The method for recovering tin, lead and zinc resources in low-grade tin middlings by a silicon reduction fluorination roasting method according to claim 1, wherein the silicon material consumption is 1-15wt% of the tin middlings.

6. The method for recovering tin, lead and zinc resources in low-grade tin middlings by using a silicon reduction fluorination roasting method according to claim 1, wherein in the roasting, the roasting temperature is 900-1200 ℃ and the roasting time is 30-180min.

7. The method for recovering tin, lead and zinc resources in low-grade tin middlings by using the silicon reduction fluorination roasting method as claimed in claim 1, wherein the tin middlings are ground to 20-300 meshes before being mixed.

8. The method for recovering tin, lead and zinc resources in low-grade tin middlings by using a silicon reduction fluorination roasting method according to claim 1, wherein the silicon material is ground to 20-300 meshes before mixing.