CN103910428A - Comprehensive utilization method of titanium dioxide waste acid - Google Patents

Abstract

A comprehensive utilization method of titanium dioxide waste acid adopts titanium dioxide waste acid as a component of a Fenton reagent, and uses the titanium dioxide waste acid in a waste water deep treatment process by a Fenton oxidation method; the titanium dioxide waste acid is waste acid generated by filtering hydrolyzed titanium sulfate, or waste water obtained by washing metatitanic acid generated by filtering hydrolyzed titanium sulfate, or a mixture of the above two. The method of the invention realizes maximum application of titanium dioxide waste acid, saves a lot of ferrous sulfate and sulfuric acid buying expenses for sewage treatment enterprises, generates no new secondary pollutants, and does not change the amount and components of finally generated sludge for sewage treatment enterprises.

Description

A kind of titanium pigment waste acid method of comprehensive utilization

Technical field

The present invention relates to waste water reclamation and utilize field, is a kind of titanium pigment waste acid method of comprehensive utilization specifically, also can be described as a kind of new purposes of titanium pigment waste acid.

Background technology

Approximately 150,000 tons of China's titanium white powder annual production, wherein mainly adopt Production By Sulfuric Acid Process, produce 1t titanium dioxide and need use sulfuric acid 4～5t.The vitriol oil decomposes in ilmenite process, most of sulfuric acid reacts with ilmenite, the generation titanium of solubility and the vitriol of iron, and small portion sulfuric acid does not react and becomes free acid and be present in resultant, after water and waste acid dip, become acid sulfate liquor.In the time of titanium hydrolysis, titanium sulfate hydrolysis has generated metatitanic acid and sulfuric acid, and the sulfuric acid concentration of solution is increased, and finally obtains the metatitanic acid of solid and the Waste Sulfuric Acid of liquid by filtering and washing.About every production titanium dioxide 1t, can obtain filtrate spent acid 8～10t of sulfur acid 250～350g/L and the sulfur acid spent acid of the washing for the first time 8～10t in 50g/L left and right, and a large amount of washing acid waste water of pH2～3.Titanium pigment waste acid is a kind of refuse producing in sulfuric acid method titanium pigment production process, not only makes enterprise bear heavy economical load, has brought destructive strike more to ecotope around.

In sulfuric acid method titanium pigment production process, produce so many spent acid, except the dense spent acid of a part returns to the dilution water and leaching water for acidolysis, the dense spent acid of another part and the once light spent acid of washing, and a large amount of acid waste waters of later stage washing are all discharged.In the time that these spent acid enter waters, will cause a series of harm:

(1) pollute waters, had influence on industrial and agricultural production and people life water.

(2) FeSO in spent acid ₄can consume the dissolved oxygen in water, make the hydrobionts such as fish can not get oxygen and death has destroyed the eubiosis in water.

(3) corrode water drain, damaged house.

(4) acidifying soil, make crop failure.

(5) increase damages, affected factory's group relation.

(6) increased expense and the Environment Protection and Drainage of Pulled Water expense of anti pollution facilities, product cost is improved, economic benefit reduces.

Traditional titanium white waste acid treatment process is with lime neutralization, but can make the cost of titanium white products production increase, and uses after lime treatment spent acid solution simultaneously, produces a large amount of mud, forms secondary pollution, is worthless.

Someone reclaims titanium compound (accounting for 4% left and right) wherein by complicated technique, but gets nowhere temporarily after being converted into tetra-sodium titanium.

Other enterprise sets about adopting nanofiltration membrane that titanium pigment waste acid is separated, obtain byproduct sulfuric acid, still contain ferrous sulfate and part spent acid because separate thorough the method remaining liquid after extraction sulfuric acid, and the reason such as film cracky, power consumption height in operational process, fluctuation of service, the consumption problem such as seldom on the low market of gained sulfuric acid concentration, treatment cost makes enterprise be difficult to bear equally simultaneously.

Someone produces the water conditioners such as bodied ferric sulfate with it, this technique needs the operations such as neutralization, removal of impurities, oxidation, hydrolysis, polymerization very complicated, someone is attempting this spent acid to obtain good effect for the neutralization of alkaline waste water processing, but the quantity of this range of application and use is very limited, can not meet the demand of existing titanium dioxide enterprise at all.

Summary of the invention

For solving the above-mentioned defect of prior art, the present invention proposes a kind of energy-saving and emission-reduction, reduce waste water control cost and realize the titanium pigment waste acid method of comprehensive utilization of resource recycling.

Principle of the present invention be by titanium pigment waste acid for Fenton oxidation style wastewater deep treatment process, its feature is the treatment of wastes with processes of wastes against one another, realizes doulbe-sides' victory.The effect of titanium pigment waste acid is sulfuric acid and the two kinds of raw materials of ferrous sulfate that replaced in the wastewater treatment of Fenton oxidation style, and in sour environment, under the catalysis of ferrous ion, hydrogen peroxide is excited, and produces hydroxyl radical free radical.Hydroxyl radical free radical has high strong oxidizing property makes the organic pollutant moment " burning " in waste water, changes into water and carbonic acid gas, thereby has removed the COD in sewage.

Fenton oxidation style wastewater deep treatment process principle

Photon energy on OH active group is equivalent to the heat energy of 3327 ℃ of high temperature, be enough to make organism " burning " rapidly, and final oxygenolysis is H under this high temperature ₂o and CO ₂.

Fenton reagent passes through Fe under acidic conditions ²⁺excite, make hydrogen peroxide produce HO there is high oxidisability, its oxidizing electrode current potential is 2.80eV, in common oxygenant, is only second to F.

Fe ²⁺?+H ₂0 ₂→Fe ³⁺?+HO·+HO ^-

Fe ³⁺?+H ₂0 ₂→Fe ²⁺?+HOO·+H ^＋

Fe ²⁺+HO·→Fe ³⁺?+?HO ^-

HOO·+?Fe ³⁺→Fe ²⁺+?O ₂+?H ^＋

HO·+H ₂O ₂→HOO·+?H ₂O

Fe ²⁺+HOO·→H0 ^2-+Fe ³⁺

Fenton reagent is brought into play its oxygenizement under acidic conditions, also complexing, precipitin reaction is occurring simultaneously, and the pH doing when for maintenance effluent quality neutrality especially improves process and will more be conducive to the generation of Fenton coagulating.

〔Fe(H ₂O) ₆〕 ³⁺+H ₂O?→〔Fe(H ₂O) ₅OH〕 ²⁺?+H ₃O ^＋

〔Fe(H ₂O) ₅OH〕 ²⁺?+H ₂O?→〔Fe(H ₂O) ₄(OH) ₂〕+H ₃O ^＋

Concrete technical scheme of the present invention is that integral part using titanium pigment waste acid as Fenton reagent is for Fenton oxidation style wastewater deep treatment process; Described titanium pigment waste acid is after titanium sulfate hydrolysis, to filter the spent acid producing, or after titanium sulfate hydrolysis, filters the waste water that the metatitanic acid that obtains obtains through washing, then or the two mixing.

Such scheme is more preferably:

Described Fenton oxidation style wastewater deep treatment process comprises the following steps:

(1), in pending waste water, add titanium pigment waste acid to obtain the waste water mixed solution of pH value 3.0-4.0;

(2), under whipped state, in waste water mixed solution, slowly add hydrogen peroxide to carry out oxidizing reaction;

(3), under whipped state, add sodium hydroxide to waste water mixed solution, the pH value of waste water is transferred to 6.0;

(4), under whipped state, add polyacrylamide, make the flocculation of waste water mixed solution;

(5), staticly settle, supernatant liquor discharges as water up to standard, lower sediment thing is that water treatment sludge is removed water extracter.

The present invention has following characteristics:

(1) titanium pigment waste acid is applied to greatest extent, and does not increase any processing cost of titanium pigment waste acid, has really verified " refuse is the resource that has misplaced position " the words.

(2) waste water control enterprise has saved a large amount of ferrous sulfate and sulfuric acid buying expenses, accounts for 50% of Fenton oxidation style wastewater deep treatment process total cost.

(3) there is no newly-increased secondary pollutant, for waste water control enterprise, final amount of sludge and the composition generating do not change.

(4) Fenton oxidation style wastewater deep treatment process is larger to the demand of sulfuric acid and ferrous sulfate, and this is also the universal major cause of this technique of restricting current, has had after the method the development for this technique that wide prospect is provided.

Embodiment

The present invention is done further open with specific embodiment below.

Titanium dioxide wastewater main component is H ₂sO ₄10g/L-280g/L inequality, and contain a small amount of ferrous sulfate and titanyl sulfate; Titanium pigment waste acid is to produce in the hydrolyzing process of titanium workshop, and its major ingredient is H ₂sO ₄about 20%-25%, FeSO ₄approximately 18%, and a small amount of titanyl sulfate, spent acid analysis report:

Table 1 titanium pigment waste acid analysis report

Composition

H 2SO 4

FeSO 4

Titanium salt

Mn

CaO

MgO

V

Content %

20-25

18

＜1

0.3

0.04

0.01

0.001

The step of Fenton oxidation style wastewater deep treatment process is as follows:

The first step: add titanium pigment waste acid in waste water, make pH value drop to 3.0-4.0.

Second step: under whipped state, slowly add hydrogen peroxide.

The 3rd step: under whipped state, add sodium hydroxide, the pH value of waste water is transferred to 6.0.

The 4th step: add PAM under whipped state, make the flocculation of waste water mixed solution.

The 5th step: staticly settle, supernatant liquor is water discharge up to standard (lower than CODcr50mg/L), and lower sediment thing is that water treatment sludge is removed water extracter.

To a 60000m ³the sewage work of/d, in the time adopting above-mentioned Fenton oxidation style sewerage advanced treatment process, the in the situation that of influent COD cr500mg/L, water outlet CODcr50mg/L, can fully utilize 300 tons of titanium pigment waste acids every day.Result of use is as follows:

Be equivalent to replace 75 tons of the bright sulfur acid of 98% concentration, 60 tons, 90% ferrous sulfate, saves 2.7 ten thousand yuan of sulfuric acid expenses, 1.26 ten thousand yuan of ferrous sulfate expenses every day, year can save 1,425 ten thousand yuan.

Claims (2)

1. a titanium pigment waste acid method of comprehensive utilization, is characterized in that, the integral part using titanium pigment waste acid as Fenton reagent is for Fenton oxidation style wastewater deep treatment process; Described titanium pigment waste acid is after titanium sulfate hydrolysis, to filter the spent acid producing, or after titanium sulfate hydrolysis, filters the waste water that the metatitanic acid that obtains obtains through washing, then or the two mixing.

2. titanium pigment waste acid method of comprehensive utilization according to claim 1, is characterized in that, described Fenton oxidation style wastewater deep treatment process comprises the following steps:

(1), in pending waste water, add titanium pigment waste acid to obtain the waste water mixed solution of pH value 3.0-4.0;

(2), under whipped state, in waste water mixed solution, slowly add hydrogen peroxide to carry out oxidizing reaction;

(3), under whipped state, add sodium hydroxide to waste water mixed solution, the pH value of waste water is transferred to 6.0;

(4), under whipped state, add polyacrylamide, make the flocculation of waste water mixed solution;

(5), staticly settle, supernatant liquor discharges as water up to standard, lower sediment thing is that water treatment sludge is removed water extracter.