SU865837A1 - Method of utilizing sulfuric acid waste water in titanium dioxide production - Google Patents

Description

(54) METHOD OF UTILIZATION OF SULFUR ACID SEWAGE TITANIUM BIOXIDE PRODUCTION The invention relates to the production of titanium dioxide and can be used in hydrometallurgy of fusible and rare metals. In the production of titanium dioxide, a large amount of sulphate-containing sewage containing hydrated titanium dioxide (GDT) is formed, mainly in an undissolved state. The drains have the following approximate composition, g / l: TiOi2-4; 50 feSO and M Methods are known for purification of aqueous suspensions from solids, most of which are mainly used for precipitation operations using various flocculants HZ to intensify the process. However, these methods are ineffective with large wastewater streams and a high content of finely dispersed solid phase, which and is hydrated titanium dioxide. The closest to the invention according to the technical essence and the achieved result is a method of utilization of waste dioxide dioxide production, including the settling of the solid phase of gas turbulence in thickeners using flocculant polyacrylamide to intensify the process and the subsequent precipitation of heavy metal ions simultaneously neutralizing the acidity with lime milk. Thereafter, the effluent is directed to the ammono 2 ish. The disadvantage of this method is that it provides only the necessary treatment for subsequent removal from production and makes it impossible to return wastewater for reuse, since they contain precipitated metal hydroxides and no longer contain acids. The purpose of the invention is the reuse of wastewater from the production of titanium dioxide, as well as the elimination of losses, hydrated titanium dioxide and sulfuric acid. This goal is achieved by the fact that according to the method, which includes processing with polyacrylamide (PAA} and settling of the solid phase, the wastewater is additionally treated with a collecting agent — a mixture of alkyl benzyl dimethyl ammonium chlorides containing 17-20 atoms, carbon in the alkyl part of the molecule.

In this case, the collecting agent is preferably introduced at a concentration of 120150 mg / l.

The set of operations for settling and flotation of the solid phase with this surface-active substance (surfactant) provides complete extraction of the product — the solid phase of hydrated titanium dioxide without extracting high salt background and without changing the acidity of wastewater, as well as reuse of acid and titanium dioxide.

Pretreatment of wastewater of negligible amounts of polyacrylamide 10-50 mg / l (used according to the regulations, but in large concentrations x improves the surface properties of titanium dioxide and during subsequent flotation makes it possible to achieve the desired effect. At the same time, the total consumption of reactants is reduced.

The effect of pretreatment of solid PAA on the degree of extraction of titanium dioxide using is shown in Table 1.

Frater (C-CjQ Table 1

Comparative data on the dependence of the degree of extraction — the solid phase on the carbon content of the alkyl portion of the reagent molecule and its concentration — are presented in Table 2.

table 2

{.

KOHuawTpa- - The degree of extraction of gas turbines,%

AI reagent-11

ta mg / l I J I h1-ao

For conentractions greater than 150 mg / l (C, 2d), the goal is achieved, but it is economically disadvantageous, since the recovery rate will remain at 100%.

Example 1. Utilization is subjected to waste water after a sedimentation operation in a known manner. The method is carried out in a laboratory flotation unit consisting of a glass column with a diameter of 30 m and a height of 400 mm, the bottom of which is the Schott filter 4, a rheometer and compressor,

200 ml of wastewater with a collector concentration of 120 mg / l is poured into the column and floated for 10 minutes. After the flotation, the filtrate is analyzed for the content of the solid phase of gas turbine phase.

The result is 100% extraction of HDD. The solution is clear.

Example 2. The experiment is carried out on a bench-mounted impeller plant of factory manufacture with a working chamber volume of 1 l. Wastewater with a collector concentration of 150 mg / l is poured into the chamber and floated for 10 minutes.

The result is 100% extraction of HDT,

Example 3. In order to investigate the possibility of recycling the treated wastewater, the latter, after the extraction of the solid phase of the HD, the flotation operation is directed to the head of the technological process to the leaching stage of the melt.

Wastewater with a volume of 2 liters is used to leach 2 kg of water. After that, all technological operations are carried out in the production of titanium dioxide pigment grades. As a result, a pigment corresponding to the grade Р-1 (GOST 9808-75) is obtained.

The use of the proposed method provides in comparison with the known:

a) possible reuse of wastewater;

b) reducing the loss of product gas turbulence;

reduction of sulfuric acid losses due to its return to production;

d) prevention of environmental pollution by solid and liquid production of titanium dioxide.

Claims (2)

1. A method for utilizing titanium dioxide sulphate wastewater, which includes treatment with polyacrylamide, which is distinguished by the fact that the wastewater is additionally treated with a collecting agent 58658376 to reuse wastewater and eliminate losses of titanium dioxide and sulfuric acid. a mixture of alkylbenzyldimethylammonium sources of information, chlorides with a content of alkylprints in the examination parts of a molecule are 17-20 carbon atoms, 1. U.S. Patent 3,235,490, class 210-53, 2,. The method according to claim 1, characterized by 2. Technological regulations forgiven and the fact that the reagent-collecting-pigment titanium dioxide production The body is administered in the amount of 120-150 mg / l. on SPO Khimprom, 182-74.