CN110331279A - A kind of microwave calcining stibnite concentrate directly volatilizees the method for recycling antimony oxide - Google Patents

Abstract

The invention relates to a method for directly volatilizing antimony sulfide by microwave roasting antimony sulfide concentrate and belongs to the technical field of antimony metallurgy. In order to solve the problems of long process, high energy consumption, large consumption, low metal antimony recovery rate and high cost in the existing antimony pyrometallurgy technology, the method for directly volatilizing antimony sulfide by microwave roasting antimony sulfide concentrate includes the following steps: 1) Use antimony concentrate as raw material; 2) Put the crushed and ground antimony sulfide concentrate in a quartz boat and place it in the cavity of a microwave heating furnace; 3) Turn on the microwave and blow in oxygen-enriched air at the same time. In this process, antimony trioxide is produced by oxidative roasting; 4) Due to the easy sublimation characteristics of antimony trioxide, the generated antimony trioxide fume is discharged through the gas outlet of the microwave reactor, and the cooled flue gas passes through the dust recovery device Collect antimony trioxide with higher purity. The invention uses microwaves as the heat source, and has the advantages of short technological process, low energy consumption, high heating efficiency, simple and easy operation, and the like.

Description

A method for direct volatilization and recovery of antimony oxide by microwave roasting antimony sulfide concentrate

technical field

The invention relates to a method for directly volatilizing antimony sulfide by microwave roasting antimony sulfide concentrate and belongs to the technical field of antimony metallurgy.

Background technique

At present, there are two methods of antimony smelting: fire method and wet method, but in industry, fire method is the main method. In the fire method, most enterprises adopt volatile roasting (smelting) - reduction smelting, the main features are "low material column, thin material layer, high coke rate", which makes the process long, high energy consumption, low concentration of SO ₂ Disadvantages such as smoke pollution. The most widely used is the blast furnace volatilization smelting process, which mainly oxidizes Sb ₂ S ₃ in antimony sulfide concentrate to volatile Sb ₂ O ₃ through oxidation roasting. The volatilized Sb ₂ O ₃ enters the flue gas, and the crude antimony oxide can be obtained by further cooling and recycling the flue gas. The process has long technological process, high energy consumption and low production efficiency.

In order to solve the problems of high energy consumption and low production efficiency, patent CN 103173637 B discloses an oxygen-enriched smelting method of antimony sulfide concentrate and a side-blowing furnace. Oxygen-enriched oxidation is carried out in the furnace. The method realizes autothermal smelting of antimony sulfide concentrate and reduces energy consumption. But because it needs batching and granulation first, and the process is more complicated.

Patent CN 107858530 A discloses a method for oxygen-enriched smelting of antimony sulfide ore. Although this method improves production efficiency, it needs to crush and granulate antimony sulfide ore during the smelting process, and preheats oxygen-enriched air . Result in long technological process and inconvenient operation.

Due to the above deficiencies and shortcomings, the above methods have not been applied in industrial production. The main antimony smelting process in my country at this stage is still the blast furnace volatilization smelting. Therefore, it is urgent to seek a method for smelting antimony with short technological process and low energy consumption.

As a new green metallurgical technology, microwave metallurgy has been applied in metallurgical processes such as beneficiation, grinding, drying, roasting, calcination, sintering, reduction, oxidation, smelting, purification and purification. Compared with traditional heating methods, it has the following characteristics: (1) selective heating, fast heating rate and high heating efficiency; (2) friendly to the environment; (3) low energy consumption. Patent CN 105948123A discloses a method for preparing low-sulfur molybdenum trioxide, which achieves high-efficiency roasting of molybdenite by using microwave pretreatment. The advantages of microwave heating are comprehensively utilized.

Microwave, as a green and efficient heating method, directly heats the material through the energy dissipation of microwaves inside the material. Therefore, the heat transfer direction of the sample is heated from the inside to the outside through the microwave, compared with the traditional outside-to-in Heating method, microwave heating method is more conducive to the volatilization of antimony oxide. In addition, antimony sulfide concentrate has a high dielectric constant (8~30) and dielectric loss (0.2~0.8) in the microwave frequency band, and has a strong response to microwaves, while other components in the mineral have a dielectric constant (4~0.8). 12) The response to microwaves is weak, and the characteristics of microwave selective heating can be well utilized. Therefore, the antimony sulfide concentrate can absorb waves preferentially and undergo oxidation reaction, and the antimony oxide product can quickly reach the melting point (655°C) and is more volatile. Therefore, the application of microwave in roasting antimony sulfide concentrate to volatilize the antimony sulfide has a broad application prospect.

Contents of the invention

Aiming at the problems of long process flow, high energy consumption, high consumption, high cost and serious environmental pollution in the volatilization and smelting of antimony sulfide concentrate through blast furnace, the present invention proposes a process method for directly volatilizing antimony sulfide by microwave roasting antimony sulfide concentrate. The invention is realized through the following technical solutions.

A method for directly volatilizing antimony sulfide by microwave roasting antimony sulfide concentrate, the specific steps are as follows:

(1) Antimony concentrate is selected as the starting material, the mass percentage of Sb is 35-55%, and the mass percentage of S is > 20%;

(2) Grind the antimony concentrate material selected in step (1), take 40~200 mesh antimony sulfide concentrate and place it in a quartz boat to 2.5~5.0cm, place it in a microwave oven with a power of 0~ 20kW, in a heating furnace cavity with a frequency of 2450Hz±50Hz or 915Hz±50Hz;

(3) Turn on the microwave, and at the same time blow air in at a rate of 1.5~2.0m ³ /h, adjust the output power of the microwave, and roast the finely ground antimony sulfide concentrate from room temperature at 50~100/min in step (3) In the first heating stage of the process, the temperature is rapidly raised to 200~300℃ at a temperature rising rate of 50~100℃/min, and the temperature is kept for 30~60min; in the second heating stage, the temperature is raised to the roasting temperature at a temperature rising rate of 20~40℃/min; the temperature is raised rapidly To 950~1050℃, keep warm for 1~2h;

(4) Smoke and dust recovery, the flue gas produced during the rapid heating and roasting process is discharged through the outlet of the microwave reactor, and the smoke and dust are collected. The collected smoke and dust are thick antimony oxygen powder containing antimony trioxide powder, containing antimony mass percentage Content greater than 80%;

(5) After step (2) heat preservation for 1~2h, turn off the microwave, and take out the residual slag after natural cooling.

Further, the antimony sulfide concentrate in the step (1) contains the following mass percentage components: antimony 42.444%, sulfur 35.075%, silicon 17.184%, iron 5.026%, arsenic 0.122%, lead 0.090%, zinc, 0.060%;

Further, during the heating process in the step (3), the antimony sulfide in the antimony sulfide concentrate undergoes the following reaction and enters the flue gas:

Further, the crude antimony oxide obtained through soot recovery in the step (3) can be used for further reduction to obtain metallic antimony.

The beneficial effects of the present invention are:

(1) This method uses microwaves to directly roast the antimony sulfide concentrate to volatilize the antimony sulfide in it, which has a short process flow, less environmental pollution and easier operation;

(2) Due to the high dielectric constant and dielectric loss of antimony sulfide concentrate in the microwave frequency band, it has a strong response to microwaves, and the characteristics of microwave selective heating, the heating efficiency of materials is high, and the reaction rate is fast. The obtained products Good quality;

(3) Due to the "body heating" characteristic of microwave, the whole material is evenly heated, no temperature gradient is generated during the oxidation process, and the product composition and particle size are uniform.

[Description of drawings]

Fig. 1 is a schematic diagram of the structure of a microwave tube furnace device used in the present invention.

In the figure: 1-oxygen-enriched air storage tank, 2-flow controller, 3-air inlet, 4-quartz tube, 5-quartz crucible, 6-digital display system, 7-current and voltage display, 8-microwave power Controller, 9-emergency stop button, 10-air outlet, 11-dust recovery device.

Fig. 2 is a flow chart of the specific implementation of the present invention.

specific implementation plan

The present invention will be further described below in combination with specific embodiments.

Example 1

First, grind the antimony sulfide concentrate to 150 mesh, then take 40g of the ground antimony sulfide concentrate into a quartz boat, spread it to a thickness of 2.5cm, and place it in the wave heating furnace cavity.

Turn on the power, and at the same time blow air into the microwave cavity at a speed of 1.5cm ³ /h, and adjust the output microwave power to 6kW and the output frequency to 2450MHz±50Hz through the microwave controller of the microwave equipment.

Observe the temperature change rate in real time through the equipment display, control the heating rate to 50°C/min, rapidly raise the temperature to 200°C, keep warm for 40 minutes and heat to 950°C at a temperature rise rate of 20°C/min, during the heating process, the smoke generated by roasting to recycle. Adjust the microwave power to control the heating temperature at 950 ° C for 40 min.

After roasting is complete, stop bubbling air and turn off microwave. After natural cooling, remove the residual slag. The cooled flue gas is recovered and analyzed. The collected antimony oxide powder contains more than 80% antimony by mass.

Example 2

First, grind the antimony sulfide concentrate to 180 mesh, then take 60g of the ground antimony sulfide concentrate into a quartz boat, spread it to a thickness of 3.0cm, and place it in the wave heating furnace cavity.

Turn on the power, and at the same time blow air into the microwave cavity at a speed of 1.8cm ³ /h, and adjust the output microwave power to 12kW and the output frequency to 2450MHz±50Hz through the microwave controller of the microwave equipment.

Observe the temperature change rate in real time through the device display, control the heating rate to 70°C/min, rapidly raise the temperature to 250°C, keep warm for 40 minutes and heat to 1000°C at a temperature rise rate of 40°C/min, during the heating process, the smoke generated by roasting to recycle. Adjust the microwave power to control the heating temperature at 1000°C for 50min.

After roasting is complete, stop bubbling air and turn off microwave. After natural cooling, remove the residual slag. The cooled flue gas is recovered and analyzed. The collected antimony oxide powder contains more than 80% antimony by mass.

Example 3

First, grind the antimony sulfide concentrate to 200 mesh, then take 90g of the ground antimony sulfide concentrate into a quartz boat, spread it to a thickness of 4.0cm, and place it in the wave heating furnace cavity.

Turn on the power, and blow air into the microwave cavity at a speed of 1.8cm ³ /h at the same time, adjust the output microwave power to 18kW and the output frequency to 2450MHz±50Hz through the microwave controller of the microwave equipment.

Observe the temperature change rate in real time through the device display, control the heating rate to 100°C/min, rapidly raise the temperature to 300°C, keep it warm for 50 minutes, and heat to 1050°C at a temperature rise rate of 50°C/min. gas is recycled. Adjust the microwave power to control the heating temperature at 1050°C for 60min.

After roasting is complete, stop bubbling air and turn off microwave. After natural cooling, remove the residual slag. The cooled flue gas is recovered and analyzed. The collected antimony oxide powder contains more than 85% antimony by mass.

Claims (7)

1. A kind of method of antimony trisulfide 1. microwave calcining antimony trisulfide directly volatilizees, it is characterised in that specific step is as follows:

   (1) select antimony concentrate as starting material, the mass percentage of Sb is 35 ~ 55%, S mass percentage > 20%；

   (2) antimony concentrate material selected in step (1) is ground, takes stibnite concentrate (wherein 200 mesh of 40 ~ 200 mesh 80% or more accounting) it is placed in quartz boat, it is placed on the microwave heating furnace cavity that microwave frequency is 2450MHz or 915MHz It is interior；

   (3) open microwave, while blasting oxygen-enriched air, adjust microwave output power, will be levigate after stibnite concentrate from room temperature It is warming up to 850 ~ 1050 DEG C in two stages, keeps the temperature 0.5 ~ 2h;

   (4) fume recovery, generated flue gas is discharged through microwave reactor gas outlet in heating and roasting process, collects Flue dust；

   After step (2) keep the temperature 0.5 ~ 2h, microwave is closed, remaining slag is taken out after natural cooling.
2. 2. the method for microwave calcining stibnite concentrate volatilization antimony trisulfide according to claim 1, it is characterised in that: the step Suddenly stibnite concentrate tiles in quartz boat with a thickness of 2.5 ~ 5.0cm in (2).
3. 3. the method that microwave calcining stibnite concentrate according to claim 1 directly waves antimony trisulfide, which is characterized in that affiliated The rate that oxygen-enriched air is blasted in step (3) is 1.5 ~ 2.0m³/h。
4. 4. the method that microwave calcining stibnite concentrate according to claim 1 directly waves antimony trisulfide, which is characterized in that affiliated Microwave power is 0 ~ 20kW, frequency 2450Hz ± 50Hz or 915Hz ± 50Hz in microwave calcining device in step (3).
5. 5. the method that microwave calcining stibnite concentrate according to claim 1 directly waves antimony trisulfide, which is characterized in that affiliated The roasting process the first heating stage is rapidly heated with 50 ~ 100 DEG C/min temperature rise rate to 300 ~ 400 DEG C in step (3), heat preservation 30 ~60min；Second temperature rise period was warming up to maturing temperature with 20 ~ 40/min temperature rise rate.
6. 6. the method that microwave calcining stibnite concentrate according to claim 1 directly waves antimony trisulfide, which is characterized in that affiliated Roasting process temperature is 850 ~ 1050 DEG C, preferably 950 ~ 1050 DEG C in step (3).
7. 7. the method that microwave calcining stibnite concentrate according to claim 1 directly waves antimony trisulfide, which is characterized in that in step Suddenly in (4), after heating obtained flue dust by gas outlet discharge, flue gas is collected with device for recovering powder or cottrell, Obtained antimonial, which can be used for further restoring, obtains metallic antimony.