JPS5934653B2 - Method for extracting valuable metals from used desulfurization catalysts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for simultaneously extracting molybdenum, vanadium, nickel and cobalt from a catalyst used for hydrodesulfurization of heavy oil.

As a hydrodesulfurization catalyst for heavy oil, a catalyst in which molybdenum and cobalt are supported on an alumina carrier is generally used.

When this is used for desulfurization, heavy metals such as vanadium and nickel, as well as sulfur and carbon contained in heavy oil, adhere to it.

As the accretion increases, the desulfurization effect also decreases, and the catalyst is discharged to be replaced with a new one.

Recovery of valuable metals from used desulfurization catalysts containing molybdenum, vanadium, nickel, cobalt, aluminum, etc. is also important for the effective use of resources.

Regarding the method of extracting valuable metals from used desulfurization catalysts, some of the metal components in used desulfurization catalysts exist in the form of sulfides. Since the extraction efficiency of both is low, many methods have been proposed to selectively extract two chemically similar groups, molybdenum and vanadium, and nickel and cobalt, respectively, using soda roasting or oxygen pressure extraction. However, there is no method to extract molybdenum, vanadium, nickel, and cobalt at the same time.

As a result of examining various methods for extracting valuable metals from used desulfurization catalysts, the inventors focused on hydrogen peroxide as an extractant and treated the used desulfurization catalysts with hydrogen peroxide. , vanadium, nickel and cobalt could be efficiently extracted.

When a used desulfurization catalyst is treated with an aqueous hydrogen peroxide solution, the sulfur bound to metal components in the used desulfurization catalyst is oxidized by the hydrogen peroxide and becomes sulfuric acid, and the oxidized molybdenum, vanadium, nickel, and cobalt are converted to sulfuric acid. Dissolved in the extract as a salt.

A method of treating a used desulfurization catalyst using hydrogen peroxide utilizes sulfur in the used desulfurization catalyst as sulfuric acid for extracting metal components.

1) The amount of sulfur present in used desulfurization catalysts varies depending on the type of crude oil, desulfurization conditions, etc., but since used desulfurization catalysts are discharged due to decreased desulfurization efficiency, they contain molybdenum, vanadium, nickel, and cobalt. It does not require the addition of acids such as sulfuric acid.

The present invention is a method for extracting molybdenum, vanadium, nickel, and cobalt by treating a used desulfurization catalyst containing molybdenum, vanadium, nickel, cobalt, aluminum, sulfur, carbon, etc. with an aqueous hydrogen peroxide solution. , the dissolution of the alumina carrier is small, and it can be extracted directly at room temperature and pressure without the need for pretreatment such as removal of sulfur, carbon, and oil, oxidation roasting, or addition of acids or alkalis. It is an economical extraction method with low energy consumption.

When extracting the used desulfurization catalyst with an aqueous hydrogen peroxide solution,
As the hydrogen peroxide concentration increases, the extraction rate of any metal component increases, but the appropriate concentration of hydrogen peroxide as an extractant is in the range of 1% to 10%.

In addition, the extraction rate of nickel and cobalt is almost unaffected by the extraction temperature, but the extraction rate of molybdenum and vanadium decreases as the extraction temperature increases, so the extraction temperature is preferably 50°C or less, and room temperature is sufficient. The reaction proceeds quickly and is almost completed in a relatively short time of 15 to 30 minutes, but the extraction time is suitable for 1 hour.

Note that Table IK shows the composition of the main components of the used deflow catalyst used in the present invention.

Next, examples will be described.

Example 1 1 gram of used desulfurization catalyst and 5 ounces of hydrogen peroxide aqueous solution with a predetermined concentration
0ml was placed in a 100772g beaker, stirred with a magnetic stirrer for 60 minutes, extracted, Mo, V, Ni, Co, and A1 in the extract were each analyzed by atomic absorption spectrometry to determine the amount dissolved, and extracted. calculated the rate.

The results are shown in Table 2.

H2O2 concentrations of 1.2%, 2.4%, and 6% solutions are 63.6%, 69.7%, and 70.9%, respectively, and the pn of the extract is 1.60, ■, and 51.1.39, respectively. Met.

Example 2 Table 3 shows the results of extracting 1 g of used desulfurization catalyst using 50 ml of 6% H20□ solution at a predetermined temperature in the same manner as in Example 1.

For all metal components, the extraction rate increased as the H2O2 concentration increased, and reached a nearly constant value at the H2O2 concentration of 2.4%.

The dissolution rate of sulfur (wt%) for Mo and V decreases as the extraction temperature increases, for Ni and Co it is almost unaffected by the extraction temperature, and for A1 it increases slightly as the extraction temperature increases. became.

The lower the extraction temperature, the better the selective extraction of Al and other metal components, so it is effective to extract at room temperature, which does not require setting or adjusting the extraction temperature.

Claims (1)

[Claims] 1. A use characterized in that molybdenum, vanadium, nickel and cobalt are simultaneously extracted by treating a used desulfurization catalyst containing molybdenum, vanadium, nickel, cobalt, aluminum, sulfur, carbon, etc. with an aqueous hydrogen peroxide solution. A method for extracting valuable metals from finished desulfurization catalysts.