DE2311964A1 - Purifying waters contg radioactive or industrial waste - with reagents conditioned with gypsum or cement - Google Patents

Abstract

Specific. chemical reagents for purifying radioactive and industrial waste waters are prepd. are conditioned by mixing the specific reagent with water, to form a soln. or suspension, and with a cpd. which sets on hydration, esp. CaSO4 (gypsum) or cement. In an example, Pb nitrate was dissolved in town water at 30-35 degrees C. Na2S soln. was added, to form a black PbS suspension which was used to mix gypsum. Paste was cast into moulds, set, de-moulded, air-dried for 5 days, comminuted to desired grain-size. Aq suspension of prod. had pH 6-7 and detoxicated industrial waste water contg. dissolved Hg by 100%.

Description

Process for the preparation and conditioning of specific chemical Reagents for the purification of radioactive and industrial wastewater Dic present The invention relates to a method for the preparation and conditioning of specific chemical reagents for the purification of radioactive and industrial wastewater.

To eliminate the elements or molecules considered undesirable Numerous specific ones come from industrial wastewater or radioactive wastewater chemical reagents into consideration, for example metallic reagents such as ferrocyanides, Phosphates, carbonates, sulfates, oxalates, oxides, dioxides, sulfides and reagents such as Chlorinated lime, percarbonates, persulfates, perititanic acid, chloramine, dichloramine, trioxymethylene, Urea, borate lime, jaryte, iviagnesia, lithopon, bentonite, asbestos, silicon dioxide, Sodium bicarbonate, sodium silicate, chlorites, chlorates, perchlorates, alginic acid, saturated and unsaturated fatty acids, carbohydrates, etc.

These are generally made by mixing themselves in aqueous solution located; 'reagents produced which, according to the conditions, produce an insoluble or poorly soluble product. This product is centrifuged after filtration or Decanting with subsequent washing or subsequent treatment, which is intended to provide the product with appropriate properties for the intended goal to lend, dried, then splintered or crushed and optionally, if it is intended to be used in columns, sieved. It is that after all obtained dry product, which forms the required specific reagent. in the The final product or specific reagent will be used with the stage of its use treating wastewater or wastewater until the required degree of decontamination has been achieved brought in contact.

Due to the fact that, in principle, reagents are not reusable are, except in the case when the solid product later according to its nature and the adsorbed amount can be assessed, they do not have to be expensive. That means that they have to be made in a simple way, need only a small amount of energy and work, and only for them Raw materials of little value may be used.

Now affects the preparation of the chemical reagents in question the aforementioned drying process has a considerable effect on the final price of the product the end. In fact, when drying specific reagents, the binding capacity of the reagent for the element or molecule to be eliminated are retained.

In general, this only works at a fairly low drying temperature Achieves what long drying times (sometimes twenty days) and large drying systems conditional. This increases the price of the product obtained in Latvian form considerably.

In addition, there are problems associated with the onditioning of the dried, often related to powdered product, for example in the form of grains in Columns should be used. It shows namely that due to the powdery state of the reagents in which they develop their greatest chemical adsorption capacity, a certain number the above-mentioned reagents cannot be used in a column.

In a column, the reagents can even be unusable, either due to their insufficient mechanical, which cause the column to clog Strength (for example with barium carbonate) or due to too large a grain size, which by reducing the solution-solids-surface area their reactivity reduces (for example with lictall powders) In addition, the reagents at Interrupted (item-wise) operations may be unusable because either their Sedimentation properties are inadequate (for example with barium carbonate) or because their use releases ions in the course of the separation reactions, which is difficult either by changing the po value or by changing the valence filter or convert precipitable colloidal compounds.

According to the invention is for the reagents obtained in aqueous solution foreseen the process of filtering (or decanting or centrifuging), drying as well as all in the course of manufacturing and conditioning the To eliminate the processes necessary for their conditioning, wherein the invention very generally intends the chemischon reagents for the purification of sewage to give such a structure that it is maintained while maintaining their fine dispersion in the starting composition to form particles or bodies of any dimensions or shapes can be conditioned.

The method according to the invention is characterized in that a Mixture of the specific chemical reagents with water and with a compound of -such a nature that it is altogether is bound by its EIydratt.

In this way, the production of the end product is considerably simplified and the powdery state of the reagents is no longer an obstacle to theirs industrial use, as the solidified product can easily be transformed into any kind of shape and size can be converted.

The solidifying chemical compound is advantageously fired Plaster of paris, Ca04. 1/2 in20, however, cement or gypsum-cement mixtures are also suitable for this Purpose suitable. Under the action of the water in the solution, the gypsum turns into CaS04. 2in20 (setting plaster of paris) and binds what is in a fine dispersion Adsorbent in its bulk.

The mixture of the reagent with water can have two forms: - the Form of an aqueous solution according to the usual method of preparation, - the form of a fine aqueous dispersion if it is insoluble metal powder.

In both cases, the plaster of paris and cement add reagents the structure indispensable for their industrial use.

The gypsum enriched with the reagent according to the invention can lead to its setting in the form of rods, which are then stacked on top of each other that the air to dry the plaster of paris will brush a large area of it can.

A suitable shape for this purpose can be that of a rod with a triangular Be cross-section.

The plaster blocks containing the specific reagent can easily be stored and transported unchanged. They can be easily crushed to obtain a substance suitable for use in a purification column desired lörnullg.

Example 1 3.5 g of manganese sulfate are dissolved in 20 ml of city water (Solution 1).

2.004 g of potassium permanganate in 40 ml of city water are added separately 40 ° C (solution 2).

While stirring vigorously, solution 1 is poured into solution 2, whereupon 100 g of plaster of paris are mixed with the aid of this suspension. The paste obtained is poured into suitable molds in which the setting takes place. After molding the blocks are allowed to air dry for a period of five days and then Shredded to the desired grain size. The product obtained gives in aqueous Suspension has a pH of 6 to 7 and detoxifies moderately radioactive, Cs 137, Waste waters containing Ce 144, Cc 60, Ru 106 and Sb 125 by 95 to 98%.

Example 2 33 g of lead nitrate are dissolved in 100 ml of city water (temp.

30 to 35 ° C). 100 ml of molar are then added with vigorous stirring Sodium sulfide poured into this solution. A black PbS suspension is obtained, with which 200 g of plaster of paris are mixed. The paste obtained is in suitable Shapes poured where it hardens quickly. After molding, the blocks are during Air-dried for a period of five days, whereupon they are down to the desired Granules are crushed.

An aqueous suspension of the product obtained has a pI value from 6 to 7 and detoxifies a solution containing mercury Industrial wastewater to 100.

The batch performance is 36 mg IIg / g reagent. HEi, which could be from the reagent, is not in low-salt solutions discovered because it was absorbed into the grains by the sulphate ions of gypsum will.

Example 3 6 g of manganese dioxide are obtained from the production sludge an inorganic ion exchanger, with a grain size of less than 0.1 mm mixed with 60 ml of city water.

100 g of plaster of paris is then added to this mixture. The paste obtained is poured into suitable molds in which the setting takes place. After molding the blocks are air-dried for five days, after which they are crushed to the desired grain size. Regarding detox a result corresponding to Example 1 is achieved.

Example 4 24 g of lead sulfide are obtained from the production sludge an inorganic ion exchanger, with a grain size of less than 0.1 mm mixed with 160 ml of city water. 200 g of plaster of paris are then added to this mixture added. The paste obtained is poured into suitable molds in which the Setting takes place. After shaping, the blocks remain in place for a period of five days dried in the air, after which they are crushed to the right grain size. With regard to the performance, a result similar to Example 2 is obtained achieved.

There are numerous advantages to using plaster of paris. It's cheap and generally inert to the specific reagents used. To his It only needs water to set. It is neutral and, due to its calcium carbonate content, has it a neutralizing power towards acidic media and is odorless, non-toxic, not allergic and does not attack the skin.

In addition, it is almost insoluble over a wide pH range.

Its low solubility in water - about 2 g per liter - only sets SO = and Ca ++ ions free. This low ion release can be used to to accumulate in insoluble form ions or ionized forms, which are either in the wastewater to be treated or due to the reaction of the chemical adsorbent are supplied with the element or elements to be eliminated.

The plaster of paris releases IDårme when it sets, which causes the drying process favored. It is incombustible. He takes 60; its weight in water on, being its crystalline structure takes it to Iiydra-Latiop by filtering and decanting or centrifugation makes it easily separable from the wastewater. Its porosity leaves by increasing its water content when mixing or by adding special ones Change products. Its setting time can be determined by various additives change very easily. It has adsorbing properties that the Effect of the specific adsorbents selected for the type of wastewater to be treated join in. Finally, if there is no radioactivity, the plaster of paris can be used for its Used in the construction industry and in public works as a filler material will.

While plaster of paris is the preferred solidifying compound, the use of cement must be considered in more limited cases, as it is alkaline and its setting time is longer.

Patent claims:

Claims (5)

P a t e n t a n s p r ü c h e 1. Procedure for preparation and conditioning of specific chemical reagents for the purification of radioactive and industrial wastewater, , d a d u r c h g e -k e D nz e i c 11 n e t that a mixture of the specific chemical rain with the water and with a compound of this nature is made to be bound by its hydration. 2. The method according to claim i, d a d u r c h g e ir, e n u -z e i c hn e t that the mixture of reagent and water consists of an aqueous solution. ). Method according to claim i, d u r c h G e k e n n -z e i c Note that the mixture of reagent and water consists of an aqueous dispersion. 4. The method of claim 1, d a d u r c h g e k e n n -z c i c Note that the hydration compound is calcium sulfate (gypsum). 5. The method of claim 1, d a d u r c h g e k e n n -z e i c Note that the hydration compound is cerient.