RU2327643C2 - Method of producing aluminium oxicloride - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to methods of producing aluminium oxychloride used as a coagulant at water purification and as a component of fragrance and cosmetic items. The method of producing aluminium oxycloride includes metallic aluminium treatment with chlorine containing solution at heating. At that, as chloride containing solution, either solutions of hydrochloric acid, aluminium chloride, and low base aluminium chloride or their mixture is used for treatment of aluminium contacting with metallic copper, taken as a compacting metal and/or powder.

EFFECT: decreases duration of the process.

5 ex

Description

The invention relates to chemical technology, in particular to a method for producing aluminum oxychloride used in water treatment and in the production of perfumes and cosmetics.

A known method of producing aluminum oxychloride, in which aluminum alloys are used as aluminum-containing raw materials, containing 70-98% aluminum and metals selected from tin, copper, magnesium, manganese, titanium, chromium and zinc, as well as silicon (SU 618343, C01F 7 / 56, 1978). The disadvantage of this process is the contamination of the solution with alloying components of the alloys.

A known method of producing aluminum oxychloride (SU 833516, C01F 7/56, 1981), in which metal aluminum is treated with hydrochloric acid in the presence of salt solutions selected from the series: copper sulfate, copper chloride, cadmium acetate, silver nitrate. The disadvantage of this process is the high consumption of expensive salts of copper, cadmium or silver, comparable to the consumption of aluminum.

A known method of producing aluminum oxychloride (RU, 2131845, C01F 7/56, 1999), in which the ingots of aluminum metal having an apparent density of (2.2-2.6) kg / dm ^{3 are} treated with a chlorine-containing solution (hydrochloric acid). The disadvantage of this method is that for its implementation it is necessary to organize the industrial production of porous metal ingots with an apparent density lower than the density of compact aluminum (2.7 kg / dm ³ ), which requires significant costs.

The closest analogue is a method for producing aluminum oxychloride, comprising passing a chlorine-containing solution (hydrochloric acid with a mass concentration of 5 to 15%) through a fixed layer of aluminum metal particles when heated from 70 to 95 ° C (US patent US 3891745, publ. 06.24.1975) . This method provides the continuous production of highly basic aluminum oxychloride with an atomic ratio of aluminum to chlorine from 1: 1 to 2: 1, but requires the use of small particles of aluminum metal with a bulk density of from 0.3 to 0.8 kg / dm ³ as raw material .

The objective of the invention is to develop a method for producing highly basic aluminum oxychloride using compact metal aluminum (including standard ingots) without significantly increasing the duration of the synthesis.

The problem is solved as follows. Aluminum metal is brought into contact with metallic copper, taken in the form of a compact metal and / or powder, and then treated with a chlorine-containing solution (hydrochloric acid, aluminum chloride, low-basic aluminum oxychloride or a mixture thereof). Due to the formation of galvanic pairs of aluminum-copper, the process of dissolution of aluminum ingots proceeds at a high speed. Copper does not pass into solution. It is preferred to place aluminum on a copper sheet pallet. In addition, it is possible to periodically introduce copper salts into the solution, accumulating cement copper in the system. Powdered copper removed from the process by unloading the finished aluminum oxychloride should be filtered off and returned to the reactor.

The essence of the invention is illustrated by examples.

Example 1

12 standard aluminum ingots (GOST 11070-74) with a total weight of 192 kg and 60 kg of copper in the form of scrap (strips, scrap, scraps of cathode metal) were loaded into an enameled reactor with a volume of 630 dm ³ . 300 l of 8.5% hydrochloric acid (density 1.04 g / cm ³ ) were poured into the reactor. By supplying steam to the jacket of the apparatus, the reaction mass was heated to 95 ° C and dissolution was carried out, maintaining a constant solution level by additional supply of water as it evaporates. The control of the process was carried out by chemical analysis of samples of the solution for aluminum and chlorine. The required atomic ratio of aluminum to chlorine (2: 1) was reached after 24 hours, after which the solution was pumped out of the apparatus and filtered. The dissolution process is described by the reaction:

2Al + HCl + 5H ₂ O = Al ₂ (OH) ₅ Cl + 3H ₂ ↑

The reaction resulted in 347 kg of a solution of highly basic aluminum polyoxychloride (mass fraction of aluminum 11.3%, mass fraction of chlorine 7.4%). 39.2 kg of aluminum (about 20% of the weight of the loaded metal) passed into the solution. Copper does not go into solution and remains unchanged in the reactor.

In the next dissolution cycle, 5 aluminum ingots (40 kg of aluminum) were loaded into the reactor, thus compensating for the loss of metal in the reactor. Again, 300 l of 8.5% hydrochloric acid were poured and the process of producing highly basic aluminum oxychloride with the same indices was repeated. The process was repeated many times.

Example 2

12 standard aluminum ingots (GOST 11070-74) with a total weight of 192 kg and 60 kg of copper in the form of scrap (strips, scrap, scraps of cathode metal) were loaded into a 630 dm ³ reactor. 33 kg of anhydrous aluminum chloride were dissolved in 300 l of water and the resulting solution was poured into the reactor. Heated the reaction mass to 95 ° C and conducted dissolution, maintaining a constant solution level by additional supply of water as it evaporates. The atomic ratio of aluminum to chlorine (2: 1) was reached after 20 hours. The process is described by the reaction:

10Al + 2AlCl ₃ + 30H ₂ O = 6Al ₂ (OH) ₅ Cl + 15H ₂ ↑

The reaction resulted in 360 kg of a solution of highly basic aluminum polyoxychloride (mass fraction of aluminum 11.1%, mass fraction of chlorine 7.3%). 33.3 kg of aluminum passed into the solution. In the next dissolution cycle, two aluminum ingots were loaded into the reactor, compensating for the loss of metal in the reactor.

Example 3

The initial chlorine-containing solution (low basic aluminum chloride) was prepared from the commercial coagulant AKVA-AURAT ™ 18 manufactured by Aurat OJSC (TU 2163-069-00205067-2007). Coagulant composition: Al ₂ O ₃ - 16.4% (Al - 8.7%), Cl - 20.9%, which approximately corresponds to the gross formula Al (OH) _1.2 Cl _1.8 .

The process was carried out as follows. A copper sheet weighing 124 kg (1650 × 850 × 10) was placed on the bottom of the apparatus with a volume of 1224 dm ³ (1700 × 900 × 800) made of titanium sheet in the form of a rectangular box with a steam jacket. 48 standard aluminum ingots with a total weight of 768 kg were loaded onto a copper sheet. 210 L of coagulant solution and 360 L of water were poured into the apparatus. After supplying steam to the jacket of the apparatus, the reaction mass was heated to 95 ° C and dissolution was carried out, maintaining a constant solution level by additional water supply.

The dissolution process is approximately described by the reaction:

2.6Al + Al (OH) _1.2 Cl _1.8 + 7.8H ₂ O = 1.8Al ₂ (OH) ₅ Cl + 3.9H ₂ ↑

The atomic ratio of aluminum to chlorine, equal to 2: 1, was reached after 18 hours. About 70 kg of aluminum passed into the solution. The obtained filtrate had a density of 1.335 g / cm ³ , weight 769 kg; composition of the solution: Al ₂ O ₃ - 23.4% (Al - 12.4%), Cl - 8.2%.

Example 4

The process was carried out in the same way as in example 3, but 100 kg of copper chloride CuCl ₂ · 2H ₂ O were pre-dissolved in water. The dissolution of aluminum with the evolution of hydrogen began already at room temperature, intensifying when heated. 20 minutes after the start of the process, the solution discolored as a result of copper deposition by aluminum, and a layer of cement copper was formed on the surface of aluminum ingots, which gradually peeled off from aluminum and coagulated. The loose powdery copper precipitate is saturated with hydrogen bubbles and is partially suspended. The atomic ratio of aluminum to chlorine, equal to 2: 1, was reached after 10 hours. Copper is completely precipitated; its mass fraction in the product is about 0.0002%. Part of the copper during pumping out of the solution remains on aluminum ingots; the copper powder exfoliated from the ingots is easily separated from the solution by filtration.

Example 5

The process was conducted in the same way as in example 3, but aluminum ingots were used after the process of example 4 (the surface of the ingots was covered with copper powder), and copper powder removed from the filter was loaded onto the surface of the ingots. The atomic ratio of aluminum to chlorine, equal to 2: 1, was reached after 12 hours. The process of example 5 was repeated several times, as the aluminum was dissolved, adding new aluminum ingots so that the metal remained at a constant level. The duration of the process remained unchanged (10-12 hours).

Claims (1)

A method of producing aluminum oxychloride by treating aluminum metal with a chlorine-containing solution by heating, characterized in that solutions of hydrochloric acid, aluminum chloride, low-basic aluminum chloride or a mixture thereof are used as a chlorine-containing solution, and they process aluminum in contact with metallic copper, taken as a compact metal and / or powder.