SU1696587A1 - Method of regeneration of spent acid steel pickling solutions - Google Patents

Abstract

The invention relates to the regeneration of spent pickling solutions, in particular to the extraction of iron from acid solutions, and can be used in various industrial fields related to the chemical treatment of metal. The purpose of the invention is to reduce the cost of process 2 and to prevent damage to the environment. The method of regeneration of spent acid solutions for pickling steel includes the introduction of iron into the solution system, followed by separation of the precipitated precipitate. As a ferrite iron, a condensation product of shale total phenols with formaldehyde and subsequent sulfonation (technical name syntan Nb 12), previously dissolved in sulfuric acid at the rate of 900 - 920 g / l at 35 - 50 ° C for 135 - 180 min, is used with continuous stirring and cooled after this to room temperature, in an amount of 0.1-0.2 ml per 1 g of iron. The use of syntan No. 12 as an iron precipitator ensures a cheaper process and prevents damage to the environment. 3 tab.

Description

The invention relates to the regeneration of spent pickling solutions, in particular the removal of iron ions from acid solutions, and can be used in various industrial fields related to the chemical treatment of metal.

The aim of the invention is to reduce the cost of the process and prevent damage to the environment.

According to the invention, a 90–92% solution of the condensation product of shale total phenols with formaldehyde and the subsequent α-sulfonation (technical name of the product syntan No. 12) dissolved in sulfuric acid (beats in.) Is introduced into waste solutions of acids containing iron ions. 1.87), at the rate of 0.1-0.2 ml per 1 g of iron ion removed from the pickling solution.

To obtain a solution of syntan No. 12 to 1 liter of sulfuric acid (sp. C. 1.87) not containing iron ions, 900 - 920 g of syntan No. 12, previously crushed to powdered, incubated for 60 minutes until a true solution is formed and cooled to room temperature. When dissolving synthesis No. 12 in sulfuric acid, it is necessary to ensure that the temperature of the solution does not exceed 50 ° C. Works J should be carried out with exhaust ventilation.

Sintan N-12 is a brownish-cherry, a brownish-colored, solid, cost 0.9 rubles / kg, not deficient, non-toxic.

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The mechanism of the reaction during the regeneration of acid solutions for steel etching can be schematically represented as follows:

he

he

-sn,

-y

- CIS + F

f

CIS - Zo3Ts

t ID

- (§Г

S.Ng-304Re

Thus, the interaction of iron ions occurs with a synthetic tanning agent along mainly hydroxyl groups with the formation of an organometallic compound precipitating. In this case, the acid is regenerated and the efficiency of the pickling solution is resumed.

When dissolved in 1 liter of sulfuric acid, syntan No. 12,900 g / l, a composition is obtained, the introduction of which in solutions leads to an increase in the content of sulfuric acid, a change in their prescription values, which is technologically inexpedient.

When dissolved in 1 liter of sulfuric acid of syntan no. 12 920 g / l, precipitation is observed, i.e. the formation of a supersaturated solution.

The time interval for introducing synan No. 12 135-180 min into sulfuric acid is optimally technological, since with a shorter time the acid heats up strongly (50 ° C), causing it to splash, with a longer time it slows down the process of dissolving synan No. 12 and increases sharply the complexity of the preparation of the solution.

When introduced into the spent acid solutions of synan No. 12 in an amount less than 0.1 ml per 1 iron, complete removal of iron ions from the solution is not ensured. An increase in the injected synan Nfe 12 over 0.2 ml per 1 g of iron ions is impractical because the effect is also achieved with a smaller amount.

Attempts to introduce solid solid product No. 12 into the waste solutions for etching steel were not obtained, since the dissolution of synthetic No. 12 was prevented by its rapid fouling with iron-organic compound, precipitation and adhesion to the walls of the bath.

To obtain a saturated and stable solution of synan No. 12, the following definitions were made. Sintan number 12, crushed to powder, in quantities of ICS, 300, 500, 600,

800,850,900,910,920,940,960 g are dissolved in 1 liter of sulfuric acid, not containing Fe + ions, in small portions, the foliar acid is introduced in 135-180 minutes with continuous

stirring and controlling the temperature of the acid, which does not exceed 35-50 ° C, is kept for 60 minutes until a true solution is formed and cooled to room temperature. The stability of the compositions is visually determined 2 and 24 hours after preparation and the optimum concentration is established at which Sint No. 12 does not precipitate (preparing a saturated solution of N1 12 syntan in sulfuric acid, beats. 1.87).

The results of the determinations are given in table. one.

The compositions of spent pickling solutions subjected to regeneration by the proposed method are presented in table. 2

The results of the regeneration of the compositions of the table. 2 are presented in table. 3

The proposed method provides for the regeneration of spent acid solutions for pickling steels and allows them to be used many times according to their intended purpose.

The extracted iron (as an iron-organic compound) is the product of

for recycling for use in the national economy. The proposed method for the regeneration of spent acid solutions can solve environmental problems, since the purity of

Wastewater.

The implementation of the proposed method does not require the use of additional equipment and space.

Claims (1)

Invention Formula The method of regeneration of spent acid solutions for steel etching, including the introduction into the solution of the precipitator of iron ions with the subsequent separation precipitation, characterized in that, in order to reduce the cost of the process and prevent environmental damage, a condensation product of shale is introduced into the solution as a precipitant total phenols with formaldehyde and subsequent ty-sulfonation, previously dissolved in sulfuric acid at the rate of 900 - 920 g / l at 35 - 50 ° C for 135 - 180 min with continuous stirring and cooled thereafter to room temperature, in an amount of 0, 1 - 0.2 ml per 1 g of iron. Table The number of grams of syntan number 12 in 1 liter of sulfuric acid 100 300 500 600 800 850 900 910 920 940 960 Light cherry transparent Cherry, clear Dark cherry transparent Dark cherry transparent Brown, transparent Dark brown, transparent Dark brown, transparent Dark brown, transparent Dark brown, transparent Dark brown, transparent, precipitation after 24 hours Dark brown, turbid, precipitation after 2 h The introduction of a 91%, solution of syntan, Ns 12, ml / gRe 2+ 0.05 / 4 0.1 / 8 0.2 / 16 0.3 / 24 0.05 / 5.1 0.1 / 10.2 0.2 / 20.4 0.3 / 30.6 Characteristics of the solution Table 2 Table3 Amount of Fe remaining in solution, g / l 48 Missing Missing Absent, a strong smell 54 None None The selection of a pungent odor from an excess of syntan No. 12