CN1616352A

CN1616352A - Process for extracting sodium bromide

Info

Publication number: CN1616352A
Application number: CN 200310105506
Authority: CN
Inventors: 李茂山
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-11-12
Filing date: 2003-11-12
Publication date: 2005-05-18

Abstract

The process of extracting sodium bromide from industrial effluent containing asaryl aldehyde has decolorizing and filtering step, and concentrating crystallization step. Before the steps, the industrial effluent is heated to evaporate, to concentrate and to form concentrated product of liquid content 10-15 wt%; the concentrated product is separated to obtain solid phase product; and the solid phase product is dissolved in water, added with hydrobromic acid to result in pH 5.5-7. The solution is decolorized, filtered, and concentrated to obtain sodium bromide. The present invention has low power consumption, short period, saving in hydrobromic acid and low cost.

Description

A kind of method of extracting Sodium Bromide

One, technical field: the present invention relates to a kind of method of extracting Sodium Bromide from trimethoxy benzaldehyde industrial wastewater.

Two, background technology: before the present invention proposes, utilize the trade effluent in the production TMB process can extract Sodium Bromide.This kind degree Beaume (Be °) be in 20 ~ 22 the trade effluent except that containing more Sodium Bromide, also contain cuprous chloride, syringic aldehyde sodium etc.In order to obtain technical grade Sodium Bromide product, adopt condensing crystal usually, high-temperature roasting, dissolving and interpolation Hydrogen bromide; Five operations of decolorization filtering and condensing crystal.That is to say, at first trade effluent is carried out concentration and evaporation and obtain the solid state crystallization material; In stoving oven, above-mentioned crystalline material is carried out high bake then; Acquisition contains the solid matter than poly-metal deoxide; This product of roasting is dissolved in water will form strong alkaline aqueous solution, adds the pH value that Hydrogen bromide reduces solution then, and terminal point is that PH=7 promptly becomes neutral solution; Just can obtain qualified technical grade Sodium Bromide with carrying out the condensing crystal processing behind this neutral solution decolouring and the elimination impurity.So can turn waste into wealth with this method, exempt the pollution of trade effluent to environment, reach the effect of protection environment.But in this production method, a large amount of energy are used for high-temperature roasting, common Sodium Bromide product per ton will carry out roasting (still taking no account of the power consumption of twice condensing crystal) with 3-4 ton coal, and the aqueous solution of product of roasting is strong basicity and must just can makes this aqueous solution be neutral (PH=7) with more Hydrogen bromide, the cost of Sodium Bromide product per ton rises significantly, and economic return descends.

Three, technology contents: the objective of the invention is to avoid above-mentioned weak point of the prior art and provide a kind of and new can reduce cost the method for the extraction Sodium Bromide of additional income.

Technical scheme: purpose of the present invention can reach by following measure, with useless inspissation, separation, the levelling pH value of not carrying out of the industry in the production TMB process; Decolorization filtering, processing such as condensing crystal, technical grade Sodium Bromide product just can obtain.

Inspissation---trade effluent is heated, obtain a kind of dense phase product, content liquid accounts for 10 ~ 15% (weight ratios) in the product.

Separate---place the separation utensil to carry out solid-liquid separation above-mentioned dense phase product, recycle in the trade effluent that operation was used before the liquid of separating mixed.Solid product is then for operation use down.This separation utensil can be a centrifugation machinery, can also be that pressure type filters machinery.

Adjust pH value---with the solid product of operation gained on the aqueous solution, just can obtain to contain the solution of Sodium Bromide, this moment, solution was slight alkalinity.Align the solution pH value with a small amount of Hydrogen bromide, make pH value between 5.5 ~ 7.0.The gained solution colour more also is mixed with suspended substance.

Decolorization filtering---utilize porous adsorbent (as gac, molecular sieve etc.) to remove the color of solution, utilize then and filter the mechanical solid particulate (comprising the suspended substance in adsorptive and the solution) that is mixed in the solution of removing.At this moment, solution becomes clear, colorless liquid.Residue after the filtration then discards.

Condensing crystal---adopt ordinary method that thereby above-mentioned solution concentration is obtained qualified technical grade Sodium Bromide crystal.

In above-mentioned all operations, inspissation and adjustment pH value are critical processes.The purpose of inspissation operation is trade effluent is condensed into dense phase product, will not form xln by its whole evaporates to dryness fully.Content liquid in this dense phase product only accounts for 10-15% (weight ratio).Separate after this dense phase product, water comes the solid product of separated and dissolved gained, just can obtain to contain the solution of Sodium Bromide, but this solution is slight alkalinity, can not obtain qualified Sodium Bromide crystal.Adjust the pH value of solution so need to utilize the hydrobromic addition of change.

Constantly add Hydrogen bromide, the pH value of above-mentioned solution will descend thereupon.When adding pH value that the excessive hydrogen bromic acid causes solution less than 5.5 the time, the sodium bromide solution of gained is carried out the condensing crystal processing, oxidizing reaction might take place hydrogen bromide separates out the free bromine element, cause Sodium Bromide to produce brilliant rubicundity, and the acidity of product does not reach requirement yet.When otherwise the Hydrogen bromide that adds was very few, the pH value of the sodium bromide solution of gained was greater than 7 o'clock, because the mantoquita chromium complex can be sneaked in the condensing crystal process and be caused the product greening in the Sodium Bromide product.Should maintain between 5.5 ~ 7 so adjust the pH value of the sodium bromide solution of pH value operation gained, i.e. 5.5≤PH≤7 o'clock just can obtain the technical grade Sodium Bromide crystalline product of white through decolorization filtering and condensing crystal.

Beneficial effect: the present invention has following advantage compared to existing technology: the present invention removes the high-temperature roasting operation from, thereby can save a large amount of energy.It is simple that the present invention simultaneously adjusts solution pH value method, and operating process is shorter, not only avoids producing strong alkali solution, can also save the Hydrogen bromide consumption of price more expensive (5000 yuan/ton).Initial estimate, the ton product energy consumption descends more than 50%, ton product Hydrogen bromide consumption decline 80-90%.So after the present invention proposed, the cost that is extracted Sodium Bromide by trade effluent greatly descended, economic benefit obviously improves.

Four, specific embodiment: the present invention is further elaborated below in conjunction with embodiment.

Trade effluent 100 grams with obtaining in the production TMB process are placed in the big mouthful of flask and carry out evaporation concentration, obtain dense phase product 30 grams, and interior middle liquid weight is 3 grams, adopts separating centrifuge that above-mentioned dense phase product is separated.Water with centrifugation after the solid product of gained all dissolve, this moment, solution PH was 7.2, added 0.4 gram Hydrogen bromide, and to make the solution pH value be 6. usefulness activated carbon decolorizings and filter with filter paper, solution after filtering is constantly heated, just can obtain 16 gram white crystals shape technical grade Sodium Bromide products.

Claims

1, a kind of method of extracting Sodium Bromide has the decolorization filtering operation, and the condensing crystal operation is characterized in that: before carrying out above-mentioned operation:

(1) trade effluent is heated inspissation, obtaining liquid content is the dense phase product of 10 ~ 15% (weight ratios);

(2) this dense phase product is separated, obtain solid product;

(3) this solid product all is dissolved in water, and adds Hydrogen bromide, make the pH value of solution be adjusted at 5.5 ~ 7;

This solution is carried out decolorization filtering, and condensing crystal obtains Sodium Bromide.