KR100250062B1 - The method for extracting novel metal element of the waste cataiyst for the waste gas purifier in automobile using a converter and electric furnace slag - Google Patents

Abstract

The waste catalyst for exhaust gas purification contains a large amount of precious metal elements such as gold, silver and platinum group elements, which are catalysts for removing environmentally harmful elements of automobile exhaust gas. It was all discarded or exported abroad.

Therefore, the present invention has been made in view of the fact that the composition of converter and electric furnace slag generated during steel smelting is very preferable as a solvent component to be added to obtain the precious metal element by melting the exhaust catalyst for exhaust gas purification using the noble metal dry dissolution method. It is intended to replace the expensive slag of quicklime or silicon dioxide.

Description

Method of Extracting Precious Metals from Automobile Waste Catalyst for Flue Gas Purification Using Converter and Electric Furnace Slag

The present invention uses platinum (Pt), palladium (Pb), rhodium (Rh), etc., from an automobile waste catalyst for exhaust gas purification (hereinafter referred to as an exhaust gas waste catalyst) that is disposed by using converter and electric furnace slag generated during steel refining. It relates to a method for extracting precious metal elements.

At present, the exhaust gas waste catalyst contains a large amount of precious metal elements such as gold, silver, and platinum group elements, which are catalysts for removing environmentally harmful elements of automobile exhaust gas. There is not much progress. In particular, the technology for extracting and refining the precious metal elements contained in the waste gas waste catalyst is still inadequate. Therefore, the waste gas waste catalyst has to be disposed of as it is, or exported to foreign countries in the state of refining.

Currently, various methods are used to extract precious metal elements from waste gas waste catalysts. However, wet methods that directly leach precious metal elements with acids or alkaline solutions are increasingly being specified worldwide due to water pollution. Most countries have adopted a noble metal dry melting method in which slag is formed by melting exhaust gas waste catalyst in a plasma furnace or an arc furnace, and precious metal elements are collected by a collecting material in a crude metal state, and then refined by a small wet method.

In the noble metal dry dissolution method, it is important to reduce the loss of precious metal elements to be extracted from the molten exhaust gas waste catalyst, and for this purpose, it is very important to maintain proper slag composition. In addition, the slag composition and basicity adjustment are very important factors in terms of recovery of noble metal elements in the exhaust gas waste catalyst, refractory maintenance, fluidity, and materialization. At present, sodium carbonate (Na ₂ CO) is used to melt the exhaust gas waste catalyst to make slag. ₃ ), using the basic components of natural solvents such as calcium oxide (CaO), calcium carbonate (CaCO ₃ ), silicon dioxide (SiO ₂ ) to reduce the flow of slag and solubility of the precious metal in the slag However, the exhaust gas waste catalyst has a high slag viscosity when directly melted in the furnace, and has a small end that is extremely difficult to properly treat in an electric furnace due to its low electrical conductivity. In addition, these raw materials are too expensive to use the raw materials as a slag adjusting agent for controlling the slag composition, and the extraction rate of the precious metal elements is uneconomical, and has a closed end that requires a lot of time to extract the precious metal elements.

The present invention contains the useful components such as iron oxide (FeO), calcium oxide (CaO) in the converter and electric furnace slag generated in the steelmaking process during steel smelting in consideration of the optimum solubility in the slag of the precious metal element waste gas waste during the dry metal melting method It is intended to extract the precious metal element from the exhaust gas waste catalyst by using it as a solvent for extracting the precious metal element during the melting of the catalyst.

Steelmaking slag is generally produced by converters, furnaces, electric furnaces, etc., and steelmaking slag having different components is discharged. Among them, converter slag among steelmaking slag is a by-product produced in the production process of steel, and since it contains valuable metals such as iron and manganese, which are generally basic and have a high specific gravity, their hardness is quite high among various slags. .

Furnace slag is composed of oxidized slag and reducing slag, both of which are similar to natural crushed stone, which has very low expansion decay rate.

As shown in Table 1, the various oxides contained in the slag are the components found in natural rocks and minerals, and the converter slag has a significant amount of iron (Fe).

The chemical composition of converter slag is by weight percent of calcium oxide (CaO) 44.8-52.3%, silicon dioxide (SiO ₂ ) 13.2-18.6%, aluminum oxide (Al ₂ O ₃ ) 0.9-2.8%, sulfur (S) 0.02-0.1 %, Iron powder (T.Fe) 14.8 to 19.2%, magnesium oxide (MgO) 2.8 to 9.6%, manganese oxide (MnO) 3.2 to 6.0%, titanium oxide (TiO ₂ ) 1.0 to 2.4%. The chemical composition of the electric furnace slag is 12.8 to 23.2% of silicon dioxide (SiO ₂ ), 14.5 to 42.7% of calcium oxide (CaO), 3.9 to 11.9% of aluminum oxide (Al ₂ O ₃ ), and iron powder (T.Fe). ) 11.2-44.1%, magnesium oxide (MgO) 4.0-13.6%, manganese oxide (MnO) 0.1-1.6%, titanium oxide (TiO ₂ ) 0.04-0.6%.

In particular, it is very important to maintain proper slag composition in order to reduce the loss of precious metal elements at high temperature melting of precious metal elements. Therefore, the slag may be added by adding expensive solvent components such as silicon dioxide (SiO ₂ ) or calcium oxide (CaO). A method of reducing the fluidity and solubility of noble metals in slag is used. In particular, in the dry metal melting method of noble metals using iron as a collecting metal, iron powder or slag containing iron is required to supply iron from slag and secure conductivity during melting.

As such, the use of waste slag generated in the steelmaking process as an alternative material, rather than using a conventionally expensive material, as a component for the direct melting of exhaust gas waste catalyst or after calcination, is an energy aspect and a valuable metal. It was preferable to improve recovery rate, shorten dissolution time and recycle resources.

1 is a process diagram of the present invention.

Hereinafter, the manufacturing method of the present invention will be described in detail.

First, the waste gas waste catalyst is pulverized with a shredder and the waste gas waste catalyst pulverized through the above process is directly put into a melting furnace or the pulverized waste gas waste catalyst is calcined to decompose resin and the like, and lead (Pb) is used. Volatile metal components such as these are removed and introduced into the melting furnace, and the converter and the electric furnace slag are also crushed by a crusher or a crusher with a diameter of about 0.1 to 10 mm or less, followed by a process of drying the water and putting it into the melting furnace. The reason for limiting the diameter of the converter and the furnace slag to 0.1 to 10 mm is that there is a fear of scattering when the converter and the furnace slag is 0.1 mm or less, and when it is 10 mm or more, the melting operation is difficult.

Thus, in melting the exhaust gas waste catalyst, the converter and the electric furnace slag introduced into the melting furnace, a crude metal that collects the precious metal elements contained in the exhaust gas waste catalyst through the melting process according to the basicity of 0.7 to 1.3 and the melting process. ) And a process of extracting the precious metal element through the wet separation process of the crude metal.

The temperature of the melting furnace is preferably about 1100 ~ 1300 ℃, the reason for adjusting the basicity in the melting furnace to 0.7 ~ 1.3 is because the flowability of slag in the basicity is the best, and it is easy to extract precious metal elements. In addition, in the melting operation of the waste gas waste catalyst, the weight of the converter and the electric furnace slag introduced into the melting furnace is preferable to be about 1/5 to 1/3 of the total weight of the raw material for heat preservation and convenience of operation. This is because when the input of the converter and the electric furnace slag is less than 1/5, it is difficult to dissolve the work, and the noble metal content of the slag increases in young cattle more than 1/3.

In the present invention, by extracting the precious metal element from the exhaust gas waste catalyst by using the converter and the electric furnace slag which was discarded as described above, it is possible not only to recycle the waste, but also to provide a method of recovering the precious metal element at the low cost and the effect of preventing pollution. To this end, preferred embodiments were carried out according to the above-described manufacturing process.

[First Embodiment]

Experiments for extracting precious metals from exhaust gas waste catalysts were carried out in direct current and plasma furnaces. In this case, the chemical composition is 44.8 to 52.3% of calcium oxide (CaO), 13.2 to 18.6% of silicon dioxide (SiO ₂ ), 0.9 to 2.8% of aluminum oxide (Al ₂ O ₃ ), and sulfur (S) of 0.02 to 0.1%, T.Fe 14.8 ~ 19.2%, Magnesium Oxide (MgO) 2.8 ~ 9.6%, Manganese Oxide (MnO) 3.2 ~ 6.0%, Titanium Oxide (TiO ₂ ) 1.0 ~ 2.4% Composition by weight percent silicon dioxide (SiO ₂ ) 12.8 ~ 23.2%, calcium oxide (CaO) 14.5-42.7%, aluminum oxide (Al ₂ O ₃ ) 3.9 ~ 11.9%, iron powder (T.Fe) 11.2-44.1% Magnesium oxide (MgO) 4.0 ~ 13.6%, manganese oxide (MnO) 0.1 ~ 1.6%, titanium oxide (TiO ₂ ) 0.04 ~ 0.6% electric furnace slag was used, and the basicity of the slag was 0.8 to base an anode connection At this time, before melting the slag, coke particles were used so that electrical contact between the heating of the furnace and the positive electrode was good, and the temperature was 1200 ° C. After charging the scrap between the top and the bottom electrode, after the arc generation, charged the exhaust gas waste catalyst, melted for about 180 minutes and then melted completely, and extracted precious metal elements from the crude metal through a wet separation process.

Second Embodiment

Crude metals were prepared in the same manner in the gas-oxygen burner crucible furnace using the converter and the electric furnace slag of the same component as Example 1, and the precious metal elements were also extracted through a wet separation process.

[Comparative Example]

The melting test for melting the exhaust gas waste catalyst using a conventional material, namely calcium oxide (CaO), was conducted in a single-electrode arc furnace, and the basicity of slag was changed to electric arc by using calcium oxide (CaO) without other additives to reduce the influence factor. In the same manner as in the first embodiment.

In order to evaluate the elution characteristics of the slag prepared in Examples 1, 2, and Comparative Example, the sample was dried and pulverized according to TCLP method, which is an environmental pollution test method, mixed with the eluent (1:20), and the temperature was 22 ± 3. After filtering by shaking at 30 ± 2 times for 4 ~ 5cm amplitude and shaking at 18 ± 2 hours, the analysis was carried out for each item and the residual content of precious metals was investigated.

The table shows leaching characteristics of the produced slag.

In addition, even when comparing the extraction rate of the precious metal element as shown in Table 3, the extraction rate of the precious metal element was higher when using the converter and the electric furnace slag compared to the conventional solvent, the case of Examples 1 and 2 when melting than the comparative example The leaching concentration was also very low, the slag in the melt had good fluidity and smooth tapping. Even in consideration of the actual operation, the examples 1 and 2 were very easy to melt, and the arc generation was very good.

As described above, the present invention uses the converter and the electric furnace slag generated in the steelmaking process during steel smelting to replace precious metal elements from the printed circuit boards of the waste electronic scraps. It can be produced at a cost, and can contribute to the prevention of pollution due to the disposal of waste gas waste catalysts, such as conventional home appliances, and the invention is an invention that the extraction rate of precious metal elements has a rather good effect even when compared to conventional solvents.

Claims (1)

The waste gas waste catalyst is crushed with a shredder, and the waste gas waste catalyst pulverized through the above process is directly put into the melting furnace or the pulverized waste gas waste catalyst is put into the melting furnace through calcination and the precious metal is discharged from the waste gas waste catalyst by the solvent. Jewelry dry melting the chemical composition to the furnace wherein the exhaust gas waste catalyst injected calcium oxide in percent by weight in the (CaO) to extract the elements 44.8 ~ 52.3%, silicon dioxide _{(SiO 2) 13.2 ~ 18.6%} , aluminum oxide (Al ₂ O ₃ ) 0.9 to 2.8%, sulfur (S) 0.02 to 0.1%, iron powder (T.Fe) 14.8 to 19.2%, magnesium oxide (MgO) 2.8 to 9.6%, manganese oxide (MnO) 3.2 to 6.0%, titanium oxide (TiO ₂ ) 1.0-2.4% converter slag and chemical composition by weight percent silicon dioxide (SiO ₂ ) 12.8-23.2%, calcium oxide (CaO) 14.5-42.7%, aluminum oxide (Al ₂ O ₃ ) 3.9-11.9 %, Electric iron slag (T.Fe) 11.2 ~ 44.1%, magnesium oxide (MgO) 4.0 ~ 13.6%, manganese oxide (MnO) 0.1 ~ 1.6%, titanium oxide (TiO ₂ ) 0.04 ~ 0.6% Is pulverized to a diameter of 0.1 ~ 10㎜ to dry the moisture, and then added, and the exhaust gas waste catalyst, the converter and the electric furnace slag is melted to have a basicity of 0.7 ~ 1.3, and contained in the waste gas waste catalyst through the melting process Waste gas purification using the converter and electric furnace slag, characterized in that the process of recovering the crude metal that has collected the precious metal element, and extracting the precious metal element through the wet separation process. Method of extracting precious metal elements from catalysts.