A kind of hydrochloride waste purifying treatment method
Technical field
The present invention relates to a kind of effluent purifying treatment process, relate in particular to a kind of hydrochloride waste purifying treatment method, belong to effluent resource and utilize field.
Background technology
Conventional hydrochloride waste treatment process has traditional neutralization precipitation method and application technology as the second resource at present.Neutralization precipitation method is current domestic processing spent acid solution most popular method, and the hydrochloric acid for the method in the alkaline matter such as alkali, lime and in spent acid makes ferrous ion precipitation simultaneously.This method need to consume a large amount of industrial chemicals such as alkali, lime, and running cost is high; In spent acid, hydrochloric acid and ferrous salt can not get recycling, and a large amount of waste residues of generation also can cause secondary pollution to environment, and this method is only suitable for the poaching wastewater processing very low in pickling finishing operation acid content.
General, effluent resource technology mainly contains direct roasting method, ion exchange method, membrane separation process, extraction process, chemical transformation, distillation method etc.
Roasting method has spray roasting and two kinds of methods of fluiddized-bed roasting: spray roasting is to be sprayed into by roasting oven top after spent acid preheating is concentrated, the direct combustion heating of coal gas in stove, furnace body temperature is 670 ℃ of left and right, the tail gas that obtains containing hydrogenchloride once absorbs and obtains hydrochloric acid through packing tower, obtains the oxide particle of iron at the bottom of stoving oven; Fluiddized-bed roasting method is to spray into the fluidized-bed containing ferric oxide fluidizing medium after spent acid solution preheating is concentrated, and coal gas is direct combustion heating at the bottom of bed, and the hydrogen chloride tail gas that roasting obtains under 850~950 ℃ of conditions once absorbs and obtains hydrochloric acid through bubble-plate column.Roasting method is by large-scale iron and steel enterprise industrial applications, but this method front-end investment is large, equipment and processing requirement strict, medium-sized and small enterprises are difficult to bear.In addition the iron oxide dust that, the absorption of hydrogenchloride furnace gas not exclusively causes hydrogen chloride in tail gas discharge beyond standards and roasting to produce all can cause secondary pollution.
Ion exchange method and membrane separation process are subject to the restriction of high density iron level, easily cause resin and film to pollute; Extraction process is had relatively high expectations to extraction agent preparation, extractant regeneration etc., and recovery hydrochloric acid is directly used in pickling procedure may affect quality product due to residual extraction agent.Chemical transformation is that free hydrochloric acid and iron protochloride are all converted into iron trichloride or ferrous sulfate, need to consume chlorine, to add iron trichloride unmarketable because iron trichloride transforms, and seldom adopts now.Ferrous sulfate method need be replaced iron protochloride with sulfuric acid and be produced ferrous sulfate, because ferrous sulfate crystallization temperature is low, need to add a set of ice maker system, and investment is large and working cost is higher.
Distillation method is that spent pickle liquor is squeezed into still kettle, under constant pressure, be heated to boiling, liquid is constantly vaporized, the steam producing reclaims as dilute hydrochloric acid after condensation, the recyclable iron protochloride of still liquid crystallisation by cooling, its advantage is neither to consume the various raw materials such as chlorine, sulfuric acid, alkali, lime, can reclaim again hydrochloric acid and ferrous salt, there is the advantages such as equipment is simple, processing cost is low, but when hydrochloride waste is distilled, can run into hydrochloric acid-water azeotrope obstacle, cause reclaiming concentration of hydrochloric acid not high, reclaim not thorough.For solving hydrochloric acid-water azeotrope problem, adopt distillation with adding salts technology, add calcium chloride, magnesium chloride to change the vapor liquid equilibrium curve of hydrochloric acid-water, improve distilling effect, improve and reclaim concentration of hydrochloric acid, still raffinate can be used for preparing compound coagulant, but this method adopts atmosphere intermission distillation, energy consumption is larger, and productivity is low; Additional calcium chloride, magnesium chloride cause working cost to increase.
Summary of the invention
The invention discloses one
The technical solution used in the present invention is: a kind of hydrochloride waste purifying treatment method, is characterized in that: concrete steps are as follows:
(1) regulate the acidity of hydrochloride waste: the acidity of hydrochloride waste is adjusted into 4~7, then adds iron protochloride and make in hydrochloride waste the ferrous salt state that reaches capacity;
(2) make hydrochloride waste be warming up to bubble point by interchanger, preheater successively saturated salt acid waste liquid, enter rectifying tower opening for feed from top to bottom, the steam dilute hydrochloric acid solution that condensation is recycled after interchanger, condenser successively of rectifying tower bottom vapour outlet;
(3) coagulant aids and dilute hydrochloric acid solution are joined and in reactive tank, carry out flocculation reaction; It is 2~3 hours that reaction times is set.
(4) dilute hydrochloric acid after flocculation is flowed in still kettle and again heated vaporization by column plate, the raffinate in still kettle flows into crystallization kettle crystallisation by cooling and obtains iron protochloride crystal, and it is 67Kpa~75Kpa that pressure is set.
Further, in described step 1, the input amount of iron protochloride is 15~25% of hydrochloride waste quality.
Further, in described step 1, the acidity of hydrochloride waste is adjusted into 5~6.
Further, in described step 3, coagulant aids is water glass or calcium hydroxide.
Further, in described step 3, the ratio of coagulant aids and dilute hydrochloric acid is 1:1.2~1.5.
Further, in described step 4, the pressure of still kettle is 70Kpa~73Kpa.
Beneficial effect: the salting-out effect of utilizing byproduct iron protochloride that the present invention reclaims to produce, effectively solve hydrochloric acid-water constant boiling solution and be difficult to the problem separating, do not need to add other raw material of cost, utilizing water or hydrochloride waste is the acidity of adjustable hydrochloride waste, has also greatly saved cost; The present invention, by regulating acidity and adding after coagulant aids, reclaims hydrochloric acid effect and significantly improves, good economic benefit and environmental benefit.
Embodiment
Implementation column below can make those skilled in the art more fully understand the present invention, but does not therefore limit the present invention among described scope of embodiments.
embodiment 1
A kind of hydrochloride waste purifying treatment method:
(1) regulate the acidity of hydrochloride waste: the acidity of 1 ton of hydrochloride waste is adjusted into 5, then adds 0.15 ton of iron protochloride and make in hydrochloride waste the ferrous salt state that reaches capacity;
(2) make hydrochloride waste be warming up to bubble point by interchanger, preheater successively saturated salt acid waste liquid, enter rectifying tower opening for feed from top to bottom, 0.78 ton of the steam of the rectifying tower bottom vapour outlet dilute hydrochloric acid solution that condensation is recycled after interchanger, condenser successively;
(3) 0.78 ton of coagulant aids water glass and 0.78 ton of dilute hydrochloric acid solution are joined and in reactive tank, carry out flocculation reaction; It is 2.5 hours that reaction times is set.
(4) dilute hydrochloric acid after flocculation is flowed in still kettle and again heated vaporization by column plate, the raffinate in still kettle flows into crystallization kettle crystallisation by cooling and obtains 0.32 ton of iron protochloride crystal, and it is 72Kpa that pressure is set.
Process after hydrochloric acid waste water according to the present embodiment method, can be recycled to concentration of hydrochloric acid and be 20% dilute hydrochloric acid, the iron protochloride rate of recovery is 32%.
embodiment 2
A kind of hydrochloride waste purifying treatment method:
(1) regulate the acidity of hydrochloride waste: the acidity of 1 ton of hydrochloride waste is adjusted into 6, then adds 0.15 ton of iron protochloride and make in hydrochloride waste the ferrous salt state that reaches capacity;
(2) make hydrochloride waste be warming up to bubble point by interchanger, preheater successively saturated salt acid waste liquid, enter rectifying tower opening for feed from top to bottom, 0.80 ton of the steam of the rectifying tower bottom vapour outlet dilute hydrochloric acid solution that condensation is recycled after interchanger, condenser successively;
(3) 0.80 ton of coagulant aids water glass and 0.80 ton of dilute hydrochloric acid solution are joined and in reactive tank, carry out flocculation reaction; It is 3 hours that reaction times is set.
(4) dilute hydrochloric acid after flocculation is flowed in still kettle and again heated vaporization by column plate, the raffinate in still kettle flows into crystallization kettle crystallisation by cooling and obtains 0.34 ton of iron protochloride crystal, and it is 75Kpa that pressure is set.
Process after hydrochloric acid waste water according to the present embodiment method, can be recycled to concentration of hydrochloric acid and be 20% dilute hydrochloric acid, the iron protochloride rate of recovery is 34%.