A method for preparing high-purity arsenic trioxide by arsenic-antimony fume reduction-alloying method

Abstract

The application relates to a method for preparing high-purity arsenic trioxide by an arsenic-antimony dust reduction-alloying method, and the specific steps are as follows: firstly, high-arsenic antimony dust, a reducing agent and metal oxides are respectively ground and uniformly mixed, and then are further transferred into a roasting furnace for reduction roasting; in the process, reduction-alloying reactions of antimony phases and metal oxides occur to form antimony alloy products in the roasting substrate, and arsenic trioxide phases are volatilized into a gas phase and recovered through dust collection. The application fully utilizes the differences in the reducibility and volatility of arsenic and antimony oxides and the strong combination ability of metallic antimony with low-melting-point metals such as tin, bismuth and cadmium, so that efficient removal of antimony from high-arsenic antimony dust and preparation of high-purity arsenic trioxide are realized.

Description

Technical Field

[0001] This invention belongs to the field of smelting technology, specifically relating to a method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying. Background Technology

[0002] Currently, there are two main methods for separating arsenic and antimony from arsenic-antimony flue dust: First, the pyrometallurgical roasting method. The basic idea is to volatilize arsenic in the material as As₂O₃, while retaining antimony in the material as a less volatile form, either in a higher valence state or as sulfides. This method is difficult to achieve deep separation of arsenic and antimony, and the antimony content in the volatiles still exceeds 1%.

[0003] Second, the wet leaching separation method is based on the different properties of As and Sb compounds, such as oxidizing power and water solubility, to separate arsenic and antimony by controlling the physicochemical conditions of the leachate, such as pH and oxygen potential. However, this method is difficult to achieve the resource recovery of arsenic. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method for preparing high-purity arsenic trioxide using an arsenic-antimony dust reduction-alloying process.

[0005] The technical solution of this invention is achieved as follows: a method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying, the specific steps of which are as follows: (1) The high-arsenic antimony-containing dust, reducing agent and metal oxide are ground separately and then mixed evenly. The amount of reducing agent added is 1%-15% of the mass of the high-arsenic antimony-containing dust, and the amount of metal oxide added is 1%-10% of the mass of the high-arsenic antimony-containing dust. (2) The mixture is transferred to a roasting furnace for reduction roasting. The roasting temperature is 200-600℃ and the roasting time is 10-120 minutes. During the roasting process, the antimony phase and metal oxide undergo a reduction-alloying reaction to form antimony alloy products that remain in the roasting substrate. The arsenic trioxide phase enters the gas phase through volatilization and is recovered through dust collection. Preferably, the reducing agent is coke, pulverized coal, natural gas, or semi-coke; Preferably, the metal oxide is tin oxide, bismuth oxide, cadmium oxide, or a mixture of two or three of the above. Preferably, the grinding particle size of the high-arsenic antimony-containing fume, solid reducing agent, and metal oxide is 20-300 mesh; Preferably, the roasting furnace is a rotary kiln, a steel belt furnace, a fluidized bed, a boiling furnace, or a stoking furnace; Preferably, the antimony content in the high-arsenic antimony flue dust is 0.6 wt.%-10 wt.%; After the above steps, the arsenic and antimony in the high-arsenic and antimony fume are separated relatively thoroughly. The main reactions are shown below: MeO+Sb2O3+C=Sb-Me alloy+CO(g) (1) As₂O₃ = As₄O₆(g) (2) The beneficial effects of this invention are: This invention fully utilizes the differences in the reducing and volatility of arsenic and antimony oxides, as well as the strong binding ability of metallic antimony with low-melting-point metallic tin, bismuth, and cadmium, to achieve efficient removal of antimony from high-arsenic and antimony flue dust and preparation of high-purity arsenic trioxide. The additive metallic oxides tin oxide, bismuth oxide, and cadmium oxide are not easily volatilized during the treatment process and will not cause new pollution to the product arsenic trioxide. Compared with other pyrometallurgical processes, the separation effect is better, and compared with wet processes, the process is simpler and the amount of additives used is smaller. Attached Figure Description

[0006] Figure 1 This is a process flow diagram of the present invention. Detailed Implementation

[0007] To better understand and implement this invention, the contents of the present invention are described in detail with reference to the embodiments. However, the contents of the present invention are not limited to the following examples.

[0008] Example 1: like Figure 1 The method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying method is as follows: First, high-arsenic antimony dust with an antimony content of 1.2 wt.%, tin oxide with an added amount of 5% by mass of high-arsenic antimony dust, and coke with an added amount of 7% by mass of high-arsenic antimony dust are ground to a particle size of 80 mesh and then mixed evenly. The mixture is then transferred to a steel strip furnace for reduction roasting. The mixture is roasted at a temperature of 400℃ for 60 minutes to obtain a tin-antimony alloy. The volatile As2O3 generated during the roasting process is recovered through dust collection.

[0009] After reduction-alloying roasting, the high-arsenic antimony-containing flue dust in the above process was tested and analyzed. The arsenic volatility rate was 97%, and the antimony content in the obtained arsenic trioxide flue dust was 0.1%. The separation of arsenic and antimony in the high-arsenic antimony-containing flue dust was relatively thorough.

[0010] Example 2 like Figure 1 The method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying method is as follows: First, high-arsenic antimony dust with an antimony content of 0.8 wt.%, bismuth oxide with an added amount of 2% of the mass of high-arsenic antimony dust, and semi-coke with an added amount of 3% of the mass of high-arsenic antimony dust are ground to a particle size of 100 mesh and then mixed evenly. The mixture is then transferred to a rotary kiln for reduction roasting. The mixture is roasted at a temperature of 350℃ for 30 minutes to obtain bismuth-antimony alloy. The volatiles As2O3 generated during the roasting process are recovered through dust collection.

[0011] After reduction-alloying roasting, the high-arsenic antimony-containing flue dust in the above process was tested and analyzed. The arsenic volatilization rate was 98%, and the antimony content in the obtained arsenic trioxide flue dust was 0.08%. The separation of arsenic and antimony in the high-arsenic antimony-containing flue dust was relatively thorough.

[0012] Example 3 like Figure 1 The method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying method is as follows: First, high-arsenic antimony dust with an antimony content of 10.0 wt.%, cadmium oxide with an added amount of 10% of the mass of high-arsenic antimony dust, and coal powder with an added amount of 15% of the mass of high-arsenic antimony dust are ground to a particle size of 300 mesh and then mixed evenly. The mixture is then transferred to a fluidized bed furnace for reduction roasting. The mixture is roasted at a temperature of 500℃ for 120 minutes to obtain cadmium-antimony alloy. The volatile As2O3 generated during the process is recovered through dust collection.

[0013] After reduction-alloying roasting, the high-arsenic antimony-containing flue dust in the above process was tested and analyzed. The arsenic volatility rate was 91%, and the antimony content in the obtained arsenic trioxide flue dust was 0.3%. The separation of arsenic and antimony in the high-arsenic antimony-containing flue dust was relatively thorough.

[0014] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying, characterized in that... The specific steps are as follows: (1) Grind the high-arsenic antimony-containing dust, reducing agent and cadmium oxide separately and mix them evenly. The amount of reducing agent added is 1%-15% of the mass of the high-arsenic antimony-containing dust, and the amount of cadmium oxide added is 1%-10% of the mass of the high-arsenic antimony-containing dust. (2) The mixture is transferred to a roasting furnace for reduction roasting. The roasting temperature is 200-600℃ and the roasting time is 10-120 minutes. During the roasting process, the antimony phase and cadmium oxide undergo a reduction-alloying reaction to form antimony alloy products that remain in the roasting substrate. The arsenic trioxide phase enters the gas phase through volatilization and is recovered through dust collection.

2. The method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying according to claim 1, characterized in that: The reducing agent is coke, pulverized coal, natural gas, or semi-coke.

3. The method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying according to claim 1 or 2, characterized in that: The roasting furnace can be a rotary kiln, a steel belt furnace, a fluidized bed, a boiling furnace, or a sealed pot.

4. The method for preparing high-purity arsenic trioxide by arsenic-antimony dust reduction-alloying according to claim 1 or 2, characterized in that: The antimony content in high-arsenic antimony flue dust ranges from 0.6 wt.% to 10 wt.%.

Images