A method for promoting selective reduction of fe3o4 in copper slag by carbon-containing anode through electrochemistry

Abstract

The application provides a method for promoting selective reduction of Fe3O4 in copper slag by carbon-containing anode through electrochemistry, which comprises the following steps: weighing a certain amount of dry and finely ground copper slag and placing the copper slag in a crucible, transferring the crucible with the copper slag into a leaner electric furnace, and heating the copper slag to a specific reaction temperature at a speed of 10 DEG C / min to obtain molten copper slag; then inserting a pretreated graphite anode and an inert high-melting point metal cathode, and inputting a certain voltage to perform electrochemical regulation; after power-off, the sample is placed for a period of time, and the sample is cooled to room temperature with the furnace; and the obtained sample has copper matte in the lower layer and molten slag tailings in the upper layer. The application uses a carbon-containing anode to replace coal powder in combination with electrochemical regulation, which can not only make the carbon-containing anode penetrate into the interior of the copper slag and increase the reducible depth of the molten slag, but also ensure the continuous work of the carbon-containing anode by the intervention of the electrochemical method, thereby solving the problem of low utilization rate of coal powder in the reduction of copper slag in industry.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgy, and particularly relates to a method for promoting selective reduction of Fe3O4 in copper slag by carbonaceous anode through electrochemistry. BACKGROUND

[0002] Strengthening the recovery of copper in copper slag is an important link to ensure the security of copper resources. 80% of copper matte / copper in copper slag is difficult to recover due to the large viscosity of molten slag, which leads to the difficulty of copper matte / copper droplet settling.

[0003] The supersaturation precipitation of Fe3O4 in the smelting process is the main reason for the difficulty of copper matte / copper droplet settling: the supersaturation precipitation of Fe3O4 significantly increases the viscosity, leading to the difficulty of copper / copper matte droplet coalescence / settling in the slag. In industry, coal powder / coal block is often used to reduce Fe3O4 to FeO and add quartz to generate fayalite to avoid FeO re-oxidation, thereby reducing the solubility of Fe3O4 in molten slag. However, the density of coal powder (1.75 g / cm 3 ) is much smaller than the density of molten slag (3.7 g / cm 3 ), and it floats on the surface of the slag liquid after being put into the molten slag. On the one hand, coal powder is difficult to penetrate into the interior of the molten slag for reduction, and the reduction effect is poor; on the other hand, the copper smelting process in industry is dynamic, and the coal powder enters the furnace and floats on the surface of the slag liquid, and is discharged from the slagging port with the flowing slag liquid, and the utilization rate is low. In order to reduce the Fe3O4 in the molten slag as much as possible and reduce the viscosity of the molten slag, it is necessary to improve the utilization rate of coal powder. SUMMARY

[0004] To solve the problem of the utilization rate of Fe3O4 in copper slag by coal powder reduction in industry, the purpose of the present application is to provide a method for promoting the separation of copper slag-copper matte by electrochemical regulation of graphite reduction.

[0005] The above-mentioned purpose is achieved by the following scheme:

[0006] A certain amount of finely ground and dried copper slag (main components include Cu 0.3wt%-20wt%, Fe3O47wt%-30wt%) is weighed and placed in a crucible, the crucible with copper slag is transferred into a leaner electric furnace, and the temperature is raised to a specific temperature at a rate of 10 ℃ / min to obtain molten copper slag; then a carbon anode and an inert high-melting-point metal cathode are inserted, the system temperature is maintained, and a certain voltage is applied for electrochemical regulation; after power-off, the sample is placed for a period of time, and the sample is cooled to room temperature with the furnace; the obtained sample has copper matte at the bottom and molten slag tailings at the top.

[0007] Preferably, the specific temperature of the reaction is 1250 ℃-1350 ℃. The specific reaction temperature of electrochemical regulation is 1250 ℃-1350 ℃, and the electrochemical regulation time is 30 min-120 min.

[0008] Preferably, the inert high melting point metal comprises: tungsten, molybdenum, niobium, tantalum, vanadium, zirconium, rhenium, hafnium and alloys thereof.

[0009] Preferably, the input voltage of the electrochemical regulation is 0.60 V ~ 0.71 V; the electrochemical regulation time is 30 min ~ 120 min.

[0010] Preferably, the standing time after power-off is 15 min ~ 60 min.

[0011] Preferably, the pretreatment of the anode rod and the cathode rod is to wrap a layer of refractory material protective sleeve on the outer layer thereof.

[0012] Effects and advantages of the application

[0013] The application aims at the problems of low utilization rate of copper and insufficient reduction degree of copper slag, and provides a method for promoting selective reduction of Fe3O4 in copper slag by using carbon-containing anode by electrochemical method.

[0014]

[0015] The following benefits exist:

[0016] (1) The carbon-containing anode is used to replace the coal powder combined with the electrochemical method, which can not only increase the reducible depth of the molten slag by deeply penetrating into the copper slag, but also ensure the continuity of the carbon-containing anode by the intervention of the electrochemical method, thereby solving the problem of low utilization rate of copper slag in industry.

[0017] (2) The input voltage is controlled to regulate the electrochemical reaction process, so that the selective reduction of Fe3O4 to FeO can not only reduce the input of SiO2 in the smelting process, but also avoid the over-reduction of Fe3O4, thereby reducing the viscosity of the molten slag and strengthening the migration, coalescence and sedimentation of the copper matte droplets in the molten slag.

[0018] (3) The molten tail slag after the electrochemical intervention has a copper content of not more than 0.3%.

[0019] (4) In copper smelting, the carbon-containing anode inserted into the molten slag can fix the carbon in the slag instead of floating on the surface of the liquid slag, thereby reducing the amount of carbon overflowing from the liquid slag flowing out of the slag outlet. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Schematic diagram of carbon-containing anode promoting separation of copper slag-copper matte by electrochemical regulation. DETAILED DESCRIPTION

[0021] The following are specific implementation cases based on the technical solutions of the present application. The present application can be better understood through the following examples and in conjunction with the accompanying drawings. It should be noted that the present application is not limited to the following examples. Those skilled in the art can make non-essential modifications or changes in form and content to the present application based on the principles of the present application, and all such modifications or changes are within the scope of the present application.

[0022] Example 1

[0023] 400 g of finely ground and dried copper slag (Cu: 2.0%, magnetic iron: 12%) was weighed into a crucible and then transferred into a depletion electric furnace. At the same time, a tungsten wire and a carbon anode, which were sleeved with a corundum tube, were placed above the slag surface. Then, the temperature was raised to 1250°C at a rate of 10°C / min to obtain molten copper slag. The tungsten wire (cathode) and the carbon anode were inserted into the molten slag at the same time. After the molten slag was stable, the system temperature was maintained and a voltage of 0.6 V was applied for electrochemical intervention for 30 min. After power-off, the sample was allowed to stand for another 15 min and then cooled to room temperature in the furnace. The copper content of the smelting tailings obtained was reduced to 0.29%, and the magnetic iron content was 6%.

[0024] Example 2

[0025] 400 g of finely ground and dried copper slag (Cu: 2.0%, magnetic iron: 12%) was weighed into a crucible and then transferred into a depletion electric furnace. At the same time, a tungsten wire and a carbon anode, which were sleeved with a corundum tube, were placed above the slag surface. Then, the temperature was raised to 1250°C at a rate of 10°C / min to obtain molten copper slag. The tungsten wire (cathode) and the carbon anode were inserted into the molten slag at the same time. After the molten slag was stable, the system temperature was maintained and a voltage of 0.6 V was applied for electrochemical intervention for 30 min. After power-off, the sample was allowed to stand for another 15 min and then cooled to room temperature in the furnace. The copper content of the smelting tailings obtained was reduced to 0.29%, and the magnetic iron content was 6%.

[0026] Example 3

[0027] 400 g of finely ground and dried copper slag (Cu: 2.0%, magnetic iron: 12%) was weighed into a crucible and then transferred into a depletion electric furnace. At the same time, a tungsten wire and a carbon anode, which were sleeved with a corundum tube, were placed above the slag surface. Then, the temperature was raised to 1250°C at a rate of 10°C / min to obtain molten copper slag. The tungsten wire (cathode) and the carbon anode were inserted into the molten slag at the same time. After the molten slag was stable, the system temperature was maintained and a voltage of 0.6 V was applied for electrochemical intervention for 30 min. After power-off, the sample was allowed to stand for another 15 min and then cooled to room temperature in the furnace. The copper content of the smelting tailings obtained was reduced to 0.29%, and the magnetic iron content was 6%.

[0028] Comparative Example 1

[0029] Take 400 g of finely ground and dried copper slag (Cu: 2.0%, magnetic iron: 12%) into the crucible and then into the atmosphere furnace, and at the same time, the molybdenum wire and carbon anode covered with corundum tube are placed above the slag surface. Then, the temperature is raised to 1280°C at a rate of 10°C / min to obtain molten copper slag, and the molybdenum wire and carbon anode are inserted into the molten slag without applying voltage. After the molten slag is stable, continue to heat for 60 min, and then stand for 60 min. The sample is cooled to room temperature with the furnace, and the copper content of the smelting tail slag is reduced to 1.5%, and the magnetic iron content is 10%.

[0030] Comparative Example 2:

[0031] Take 400 g of finely ground and dried copper slag (Cu: 2.0%, magnetic iron: 12%) into the crucible and then into the atmosphere furnace, and at the same time, the molybdenum wire and carbon anode covered with corundum tube are placed above the slag surface. Then, the temperature is raised to 1280°C at a rate of 10°C / min to obtain molten copper slag, and the molybdenum wire and carbon anode are inserted into the molten slag without applying voltage. After the molten slag is stable, continue to heat for 60 min, and then stand for 60 min. The sample is cooled to room temperature with the furnace, and the copper content of the smelting tail slag is reduced to 1.5%, and the magnetic iron content is 10%.

[0032] Table 1 Comparison of partial parameters of examples

[0033]

[0034] From Comparative Examples 1 and 2, it can be seen that without adding electrochemical intervention, the reduction effect is obviously improved by using carbon anode instead of carbon powder, and the utilization rate of carbon is improved. The copper content of the slag after reaction is equivalent to that of the tail slag after further beneficiation of the smelted slag cooled and broken in the existing industrial process.

[0035] Comparative Example 2 is the main method used in the existing copper slag reduction. In the test process, the effect of carbon powder injection into the molten slag is better than that of direct use of rod-shaped carbon anode (Comparative Example 1). Carbon powder injection into the molten slag is beneficial to increase the contact area of carbon powder and molten slag and promote the reduction reaction. At the same time, in this method, carbon mainly plays the role of conducting electricity and generating CO reducing gas in anode oxidation (which is beneficial to promote reduction). Therefore, when the carbon anode enters the molten slag, it needs to be covered with a corundum sleeve to reduce the contact area with the molten slag. Without electricity, the carbon anode only retains its reduction effect, so the reduction effect is inferior to the existing industrial method.

[0036] The above only describes the preferred embodiments of the present application, and any changes and modifications made within the scope of the patent application of the present application shall be included in the scope of the present application.

Claims

1. A method for promoting selective reduction of Fe304 in copper smelter slag by carbonaceous anodes by electrochemical means, characterised in that, The method comprises the following steps: A certain amount of finely ground and dried copper residue is weighed and placed in a crucible, the crucible with the copper residue is transferred into a depleting electric furnace, and the temperature is raised to 1250-1350 DEG C at a speed of 10 DEG C / min to obtain molten copper residue; then a carbon anode and an inert high-melting-point metal cathode are inserted, and a voltage of 0.60-0.71 V is applied for electrochemical regulation for 30-120 min; after power-off, the sample is left to stand for 15-60 min, and the sample is cooled to room temperature with the furnace; the obtained sample has a lower layer of copper matte and an upper layer of molten residue tailings, and the copper content of the tailings is not more than 0.3%; the main components of the raw material copper residue include Cu 0.3-20%, Fe3O4 7-30% by mass.

2. A process for the selective reduction of Fe304 in copper slag by carbonaceous anode using electrochemical method as claimed in claim 1, wherein: The inert high-melting-point metal includes tungsten, molybdenum, niobium, tantalum, vanadium, zirconium, rhenium, hafnium and alloys thereof.

3. A process for the selective reduction of Fe304 in copper smelter slag by a carbonaceous anode using electrochemical method as claimed in claim 1, wherein: The outer layer of the anode rod and the cathode rod is sleeved with a refractory material protective sleeve.

4. A process for the selective reduction of Fe304 in copper smelter dust by a carbonaceous anode using electrochemical method as claimed in claim 3, wherein: The refractory material protective sleeve is a corundum sleeve.

Images