JPS6077938A - Method for separating and recovering metal from carbon - Google Patents

Abstract

PURPOSE:To separate and recover efficiently V and Ni from carbon contg. V and Ni by bringing an aqueous alkali soln. into contact with the carbon to obtain an aqueous alkali soln. contg. leached V and carbon contg. Ni and by extracting V from the soln. and Ni from the carbon. CONSTITUTION:An aqueous soln. of the hydroxide of an alkali metal such as Na (>=about 10pH) is brought into contact with carbon contg. V and Ni at about 80-200 deg.C for about 0.1-3hr to obtain an aqueous alkali soln. contg. leached V and carbon contg. Ni. An extracting liq. forming an ion pair with each complex ion of V, e.g., tri-n-octylamine is added to the alkali soln. contg. leached V to extract and recover V. An aqueous soln. of a mineral acid such as sulfuric acid or nitric acid is brought into contact with the carbon contg. Ni to extract Ni, and a sulfide such as gaseous hydrogen sulfide is blown into the mineral acid soln. contg. the leached metal to recover Ni as nickel sulfide.

Description

Detailed Description of the Invention The present invention is a method for separating and recovering metals from unburned carbon generated by thermal decomposition (partial oxidation) of carbon and hydrocarbons containing metals such as vanadium and nickel. It is related to.

Raw material gases for various syntheses such as ammonia synthesis, methanol synthesis, and acetic acid synthesis are produced by thermally decomposing hydrocarbons such as 9M oil, crude oil, naphtha, or coal.

The unburnt carbon generated during the thermal decomposition of hydrocarbons is usually taken out of the system as a suspension in water, then recovered through extraction, solid-liquid separation, etc., and used as part of the raw material for thermal decomposition. It is circularly reused. Note that the generation rate of unburned carbon is generally said to be 0.5 to 25 qb, although it varies depending on the type of hydrocarbons or thermal decomposition conditions.

Unburnt carbon contains concentrated metals such as vanadium and nickel, which are naturally included in hydrocarbons. In recent years, due to the depletion of high-quality hydrocarbons and soaring prices, vacuum, normal pressure, and vacuum residual oil, asphalt, petroleum coke,
The amount of various metals contained in unburned carbon is increasing as less expensive hydrocarbons such as cherry pitch but high in metal content such as vanadium-nickel are used.

When unburned carbon containing metals such as vanadium and nickel is recycled as part of the raw material for pyrolysis as described above, metals accumulate in the system and exceed the allowable limit. Otherwise, the equipment in the high-temperature section and the walls of the gasifier may be corroded, or the molten metal may solidify in the equipment in the low-temperature section, resulting in blockage of the narrow part of the equipment. cause serious problems such as

Conventionally, in view of such circumstances, there have been no proposals for methods for removing metals such as vanadium and nickel directly from hydrocarbons or from unburned carbon. What is the method for targeting hydrocarbons?

Even though it requires an extremely large amount of extraction solvent such as nitric acid, the recovery rate is only about 50%.

Because it requires large equipment, it has not yet been put into practical use. On the other hand, typical methods targeting unburned carbon include a method using a strong acid as an extraction solvent, or a method using a combination of a light hydrocarbon and a strong acid. However, these methods do not work with vanadium,
Since many metals such as nickel are leached into the acid aqueous solution at the same time, extremely complicated operations are required to recover each metal individually.

The present invention provides a method for efficiently separating and recovering carbon, particularly metals such as sodium and nickel contained in unburned carbon generated by thermal decomposition of hydrocarbons.

That is, the present invention.

(1) A first step of bringing carbon containing vanadium and nickel into contact with an aqueous alkali solution, and then separating the aqueous alkali solution from which vanadium is leached and the carbon containing nickel.

(2) A second step in which an extract that forms ion pairs with vanadium complex ions is added to the vanadium leaching alkaline aqueous solution obtained in the first step, and vanadium is transferred into the extract phase.

(3) a fifth step of bringing the nickel-containing carbon obtained in the first step into contact with an aqueous mineral acid solution, and then separating the nickel leaching mineral acid aqueous solution from the carbon; and (4) a third step. The fourth step is to add sulfide to the nickel leaching mineral acid aqueous solution obtained in step 1 and separate the precipitated nickel sulfide.

It consists of each process. This invention relates to an industrially superior separation and recovery method for metals in carbon.

In the present invention, carbon includes not only unburned carphone generated by thermal decomposition of hydrocarbons such as heavy oil, crude oil, naphtha, coal, A-air, regular oil, vacuum residue oil, asphalt, petroleum coke, Eureka pisochi, cherry pisochi, etc. Carbon containing other metals such as vanadium and nickel can be discussed.

Next, each step of the present invention will be explained in detail.

First step: Carbon containing metal is brought into contact with an alkaline aqueous solution.

Examples of aqueous alkaline solutions that can be used include hydroxides and carbonates of alkali metals such as sulfur, lium, and potassium, and aqueous solutions of ammonia. Particularly effective. There are no particular restrictions on the concentration and amount used, but it is preferably used 2 to 50 times the amount of vanadium in carbon, and the pH is preferably 10 or more.

Contact treatment c, mixer-settler type or plate tower type, etc.
Using equipment normally used for solid leaching, at room temperature or above,
(can be carried out at a temperature of 80 to 200 °C,
A treatment time of about 0.1 to 3 hours is sufficient.

Through this contact treatment, most of the metals contained in carbon, such as vanadium and calcium, are leached into the alkaline aqueous solution, and almost all of the metals, such as zinc and iron, are absorbed into the carbon without leaching out. It remains inside.

What is leaching alkaline aqueous solution of metals such as vanadium and carbon containing metals such as nickel?

For example, by operations such as filtration and decanting.

Can be easily separated.

2nd step: An extract that forms ion pairs with complex ions of vanadium is added to the aqueous alkali solution for leaching metals such as vanadium obtained in the 1st step to extract vanadium.

Tertiary amines such as tri-n-octylamine, tri-iso-octylamine + Alamine 336 (trade name, manufactured by Henkel) are particularly useful as extracts that form ion pairs with vanadium complex ions; Primene JMT (product name; manufactured by Rohm and Haas), which is an amine, Amberl, which is a secondary amine
ite LA-i+ Amberlite LA-2(
High molecular weight amines such as A11quat 3B6 (trade name; manufactured by Henkel); quaternary ammonium salts such as A11quat 3B6 (trade name; manufactured by Henkel); and neutral phosphorus such as tributyl phosphate and tri-octylphosphine oxide. Compounds; etc. can also be used.

These extracts can be used alone, but
In order to prevent loss of dissolution in water and maintain an appropriate viscosity, it is preferable to use it diluted with a solvent. The solvents include aromatic and aliphatic hydrocarbons, which are generally used as solvents for organic compounds and have low solubility in water;
alcohol.

Examples include ethers, ketones, esters, halides, and hydrocarbon derivatives, but from the viewpoint of properties and toxicity, it is particularly preferable to use chelone. Although dilution with these solvents can be carried out arbitrarily, it is preferable to dilute the extract so that the concentration of the extract is about 1 to 10 voA%.

The amount of the extract used is usually 0.1 times or more, preferably 0.5 to 5 times the amount of vanadium dissolved in the aqueous alkali solution to be treated.

The extraction operation is carried out within a temperature range in which the system remains in a liquid state, but it can usually be carried out at room temperature.

Note that, prior to the extraction operation, the p of the alkali aqueous solution to be treated is
By adjusting H, vanadium can be extracted more efficiently. The adjustment is based on the raffinate aqueous phase liquid p
It is preferable to conduct the reaction so that H is 1 to 4. Small pH
Examples of the regulator include mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid, but among these, sulfuric acid is preferred in consideration of cal/rum separation. That is, when sulfuric acid is used, calcium dissolved in the alkaline aqueous solution to be treated is precipitated as sulfur.

Calcium content can be easily separated and recovered from the raffinate aqueous phase.

Through this extraction operation, among the metals dissolved in the treated alkaline aqueous solution, only vanadium selectively forms an ion pair with the extract and migrates into the extract phase. remains in the raffinate aqueous phase. Therefore, by performing, for example, a liquid separation operation on both of the three, it is possible to selectively recover vanadium, which has the highest utility value, from among the various metals contained in the carbon.

The extracted liquid phase contains vanadium.

It can be brought into contact with an ammonia aqueous solution such as ammonia, ammonium chloride, ammonium sulfate, etc., and the vanadium component can be back extracted and recovered as a precipitate of ammonium metavanadate. At this time, the ammoniacal aqueous solution can be used such that the molar ratio of ammonia to vanadium is 2 times or more, preferably 4 to 100 times.

Further, this operation is carried out using an alkaline aqueous solution other than an ammoniacal aqueous solution such as hydric soda or carbonate nose.

After the vanadium component is back-extracted, a predetermined amount of the ammonia component is added to the back-extracted solution to form a precipitate of ammonium metavanadate.

Third step: The carbon containing nickel and the like obtained in the first step is brought into contact with a mineral acid bath solution to leach out the metal.

Examples of the mineral acids that can be used include mineral acids, nitric acid, and hydrochloric acid, among which sulfuric acid is particularly preferred. Its concentration and usage amount is 9 usually 1 to 2 ow
It is preferable to use 1 to 20 times the amount of carbon by weight.

Contact treatment is carried out using a normal solid-liquid extraction device at room temperature to 1.
It can be carried out at a temperature of 0.000C for 0.1 to 3 hours.

Through this contact treatment, metals such as nickel, zinc, and iron in the carbon are leached into the aqueous mineral acid solution.The leached mineral acid aqueous solution of the metals and the carbon are separated by operations such as filtration and decanting. I can do it.

The carbon recovered in this way is vanadium.

Since it contains almost no metal such as nickel, it can be effectively reused as a fuel, a raw material for pyrolysis, or a raw material for activated carbon.

Fourth step: Adding sulfide to the metal leaching mineral acid aqueous solution in the third step,
The nickel content is recovered as nickel sulfide.

As the sulfide, any substance that provides sulfide ions within the system is useful, such as hydrogen sulfide gas and sulfides of alkali metals such as sodium and potassium. The amount used is preferably 1.0 to 10 times the amount of nickel in the mineral acid aqueous solution.

In this operation, only the nickel dissolved in the mineral acid aqueous solution is selectively precipitated as nickel sulfide. Therefore, the nickel with high utility value can be separated and recovered by operations such as filtration and decantation. I can do it.

This operation can be carried out at a temperature between room temperature and 80°C, but in order to efficiently precipitate nickel sulfide, an aqueous solution of alkali metal hydroxide, carbonate, or ammonia is added to the mineral acid aqueous solution to be treated. and adjust its pH to 2-4.
It is preferable to adjust it to a certain degree.

Next, an example of the present invention will be described. Note that each part in each example represents 1 part by weight.

Example 100 parts of unburnt carbon generated in the gasification process by partial oxidation of petroleum coke (the composition of the carbon before this treatment is shown in the table below) was added to 200 parts of IN aqueous sodium hydroxide solution, and heated to 160°C. After stirring for 1 hour, the mixture was cooled and the carbon and vanadium leachate were separated. The P-treated carbon was washed twice with 100 parts of water, and the washing solution was added to the leachate, the P solution. As a result of measuring the metal concentration in the aqueous solution, vanadium a7oppm (leaching rate near 0%)
.

Calcium was 190 ppm, and nickel, iron, zinc, and aluminum were all less than 1 ppm. After making the aqueous solution containing vanadium acidic by adding 250 parts of IN sulfuric acid, 5 wt% IJ-n- 100 parts of octylamine diluted with Kero/N was added, and the mixture was shaken at room temperature for 30 minutes to perform liquid-liquid extraction. The raffinate aqueous phase liquid and the produced Sesoko precipitate were removed. The pin of the raffinate aqueous phase liquid is 2.5, and the concentration of vanadium is 7.
ppm (Thus, the extraction rate of vanadium from the leachate into the extract phase is 97.4 h).

Next, this extract was added with 0.8 mol/l ammonia and 2
．． Add 50 parts of an alkaline aqueous solution containing 8 mol/l ammonium chloride, shake at room temperature for 30 minutes, back extract the vanadium, remove the precipitate of ammonium metavanadate, and extract metavanadate from the extract. The recovery rate of ammonium was extremely high as 90% as vanadium.

On the other hand, the carbon separated by the filtration was added to 200 parts of a 1N sulfuric acid aqueous solution, stirred at 80° C. for 1 hour, cooled, and the carbon and metal leachate were separated by P. As a result of measuring the metal concentration in the P solution, nickel was found to be 1300 ppm.
, iron 1670ppm, vanadium 190ppm, aluminum 26 (Lppm), and trace amounts of Cal/Rum and zinc were detected.After adjusting the pH to 6 by adding aqueous sodium hydroxide solution to the filtrate, hydrogen sulfide gas was added. 0.5t
/hr for 30 minutes to collect the precipitated nickel sulfide. As a result of analyzing the nickel sulfide, it was found that 97% of the nickel in the sulfuric acid aqueous solution was recovered, and its purity was 81%.

After washing the p-separated carbon (that is, the treated carbon) with water, the metal in the carbon was analyzed, and the carbon removal rate was calculated using the following formula.

The following table also shows the results.

table

Claims (4)

[Claims] (1) A first step in which carbon containing vanadium and nickel is brought into contact with an alkaline aqueous solution, and then the alkali aqueous solution leached of sodium and the carbon containing nickel are separated. (2) A second step in which an extract that forms an image pair with vanadium complex ions is added to the vanadium leaching alkaline aqueous solution obtained in the first step, and vanadium is transferred into the extract phase. (3) A third step of contacting the carbon containing the nickel obtained in the first step with an aqueous mineral acid solution, and then separating the nickel leaching mineral acid aqueous solution from the carbon; (4) A fourth step of adding sulfide to the nickel leaching mineral acid aqueous solution obtained in the filtration step and separating precipitated nickel sulfide. It is characterized by aT degree h. A method for separating and recovering metals in carbon.