CZ22994A3 - Method of stabilizing residues after burning - Google Patents

Abstract

By the method wastes are decontaminated by the extraction of the soluble metal fractions where the extraction is carried out by chloride-containing aqueous solutions. The solution to be extractes consists of diluted solution of hydrochloric acid for treatment of residues of base character or from a solution of a chloride of alkaline or alkali-earth metal for the treatment of residues of neutral character.

Description

Field of technology

The invention relates to a process for the extraction of toxic components from waste after incineration and for their capture and removal from used solutions.

Prior art

Slags are solid wastes, non-volatile products of combustion furnaces in industrial areas. In general, they are removed by rinsing with water in a waste sump and, although they contain 3 to 30% water, they have the character of a black solid, more or less incoherent and very heterogeneous.

In the context of this proposal, the term slag will have the broadest possible meaning. It will apply to all combustion products and residues, such as slag, which may contain heavy metals, more or less capable of leaching by rainwater or groundwater runoff. It may also include fly ash, eg from the incineration of municipal waste.

Slags are often characterized by silicate-aluminum tailings, which contain metal oxides, especially iron oxides and partial oxides of chromium, copper, nickel and zinc, as well as cobalt and lead (see Table 1). Their natural composition can vary considerably locally.

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Table 1: Analysis of elements in slags from the TREDI Strasbourg (ST-l), TREDI Salaise center. II. (S. II) - a. THIRD

Saínt - Vulbas (SV 1).

Main elements in% of oxides slag ST 1 slag S II slag SV 1 SÍ02 28.89 23.90 23.58 A12 Ó3 9.70 8.46 23.12 Fe2 O3 33.95 23.80 18.91 Mn02 1.86 1.44 0.13 MgO . 1.89 0.87 1.01 CaO 5.84 9.51 8.58 > ía2 0 3.70 1.45 0.75 K2 0 0.87 1.29 0.75 'ΠΟ2 5.35 2.93 0.98 P2 Os 1.22 9.61 7.85 sulfur * 0.04 1.42 0.16

results with respect to the elementary form

Table 1: continued

Trace elements (content given with respect to element, form by ppm)

element slag ST 1 slag S II slag SV 1 barium 11500 2429 2200 béry 1ium 3.4 0.6 1 cobalt 6800 94.5 51 chrome 20800 1090 1205 copper 4800 13874 8800 gallium 58 5.0 21 niobium 124 10.1 11 nickel 5800 1468 784 rubidium 24 17 16 skandi um 6, 4 7.9 6 strontium 402 171 290 thorium 5 5 5 vanadium 484 115 105 yttrium 6 10 7 zinc 1900 893 620 zircon 282 112 98 tin 48 105 360 cadmium 0.3 3.2 1.3 Quicksilver 0.04 0.1 3.8 arsenic 6.2 14.5 50 lead 186 324.1 190

This is evident, for example, from Table 1 above, which presents the results of the analysis of the element in the slags of the three different industrial areas, Strasbourg (STI), Salaise in the department of Isera (Sil) and Saint-Vulbas, in the department of (SVÍ).

Slags generated by the incineration of industrial waste are usually deposited in landfills or in technical storage centers (C.E.T.) underground.

These slags can pose a real risk due to their content of toxic heavy metals, which are easily washed away. Heavy metals are concentrated in slags according to various physicochemical mechanisms and according to their nature and form more or less known groupings. Therefore, the risks are assessed with an interest in leaning towards the use of C.E.T., which can be differentiated according to their ability to allow storage under conditions corresponding to appropriate safety standards (after their approval).

The selective extraction methods used in pedology (soil science) make it possible to distinguish certain groupings or certain specific arrangements and provide data on the chemical form of metals and on the conditions of their possible solubility. Knowledge of these data is important to determine the procedure for possible decontamination.

The metals present in the slags may be water-soluble, interchangeable, associated with oxides and hydroxides, both amorphous and crystalline, or in the form of precipitates, such as carbonates or sulfates. Important contaminants, which can be caused by slag, are often caused by the release of metals by dissolving in rainwater or by discharging groundwater. Isotopically exchangeable cations will be replaced the faster, the weaker the electrostatic forces at negatively charged sites.

In a more general form, this knowledge has led to the definition of the mobility of an element, ie its ability to penetrate d'o ~ od <TíTu environments in which it is less and less energetically retained;

the final compartment is the liquid phase (solution).

There are different standards for comparing the risks posed by slag treatment, including the content (or soluble amount) of metals dissolved in leaching solutions or eluates obtained. In these standardized tests, the slag is leached with aqueous solutions that simulate the effect of rainwater. Such laboratory tests make it possible to estimate the real risk involved in depositing slag in a controlled landfill. They make it possible to determine the conditions under which some slags can be used in public works (circular on slags from 8.4. 92 see the following table 2). In France, for example, the protocol for the standardized test AFN05 (X31210, 1988), recommended by the Ministry of the Environment, deals with the removal of soluble substances contained in crushed slag (up to 4 mm in diameter). Other types of standards are dealt with by services belonging to the European Economic Community (CEE).

Within the various categories of leaching agents, analyzes of soluble toxic metals make it possible to classify the measured concentrations in relation to the threshold values given by French and European standards. The possibility of their use (Table 2) or storage in C.E.T. ad hoc, depending on how the products obtained by the treatment will be classified, eg as hazardous waste ”(CET type Class 1), non-hazardous waste (CET type Class 2) or inert waste (see Table 3 below).

The procedure according to the AFNOR standard 1 assay protocol (X31210, 1988) is as follows:

- demineralized water, saturated with air and CO 2 at pH 4.5 and with a resistivity of 0.2 to 0.4 MQ.cm is mixed with 100 g of slag and stirred for 16 hours at room temperature. The first leach solution is obtained by filtering the supernatant after centrifuging the mixture (2,000 g, 15 minutes). Its color, odor, conductivity and pH are measured. The pellet is then extracted twice to give two further leaching solutions (eluents). The result of the whole procedure is the determination of chemical oxygen demand (DCO), total organic carbon (COT) and mineral analysis of all three eluents.

Similar tests are performed in other countries or within C.E.E. (European Community).

They allow standards to be set, as shown in Table 3, but which can also be modified. The values given set different elution thresholds ”, corresponding to the sum of the maximum soluble amounts of each metal or other pollutants (eg soluble chlorides and cyanides) that can be tolerated with respect to each of the waste categories or classes concerned.

For contaminating metallic elements, chlorides and cyanides, French and European standards (for non-hazardous waste) require, inter alia, that the amount of each leached element be reduced during the triple extraction. Otherwise, if the solubility of a certain metal increases in at least two extracts, the time stability of the slag cannot be assumed. There would always be a risk of contamination from the renewed exchange between the deposited slag and groundwater or rainwater.

The following Tables 4, 5 and 6 give examples of the characteristic contamination of ST 1, Sil and SV 1 slags.

Table 2: Utilization of slag from kitchen waste incineration in public works. Threshold concentrations for the eluting fraction were obtained by the standardized AFXOR assay (x 31-210).

incombustible <5 X soluble faction <3 X Hg < 0.2 mg / kg dry matter Pb < 4.0 mg / kg dry matter CD < 1.0 mg / kg dry matter Cu < 20.0 mg / kg dry matter As < 2.0 mg / kg dry matter CrVI < 1.0 mg / kg dry matter sulphates < 4000.0 mg / kg dry matter chlorides < 2800.0 mg / kg dry iny COT < 1000.0 mg / kg dry matter

Such slags whose leachable fractions do not exceed the precipitate thresholds are considered to be poor leachable slags. They are therefore applicable to public works.

References: Slag Circular, Clean Technologies and Waste Service of the Ministry of the Environment, project from 8.4. 1992.

Table 3: Comparison of European and French landfill standards. The stated thresholds

------------- concentrations-for-leachateQU_fraction_with.acquired.- (100 g gross waste / 1 1 vcdy). Results are expressed as soluble anxiety, in ag / kg.

aabazp.odpady noray CEE ag / kg franc. noray class I (slag ag / kg ordinary waste noray CEE ag / kg franc.ncray cl. II (flying ash) ag / kg inert wastes ncray CEE ag / kg Bye 4-13 5-13 4-13 4-13 DCO - <5000 - - - loss annealing - <5 i - - - TOC 400-2 (300 - 400-2000 <400 <2000 arsenic III 2-10 <10 1-2 <2 <1 lead 4-20 <100 <4 <30 total kacaiua 1-5 <50 <1 <5 content chroa VI 1-5 <100 <1 - these aed 20-100 - <20 <20 przků nickel 4-20 <100 <4 - ausí Quicksilver 0.2-1 <10 <0.2 <0.2 be zinc 20-100 <500 <20 - <50ag / kg

(^ in ag / kg dry waste ^ in ag / kg gross waste

References: European Landfill Project on Landfilling

The project Ministerial Decree on Landfilling of Special Prúaysl Applies (Class I). The text of the Ministry of Life environment, ref. QEPR / SEI / SDO / AH fáv.31, 14.5. 1991.

Circular on landfilling of solid residues from the cleaning of flue gases from Aesthetic waste incinerators (Class II). Text of the Ministry of the Environment, ref. DEPR / SEI / SH / STPO / APR / MBr, 12 May 1991.

- 9 Table 4: Non-pressurized leaching test (control) _____ Slag-sa-Strassrortai— (ST-1) --------- Analysis of extracts

malted size 1.extraction 2.extraction 3. extraction total amount of extract. from gross waste (mg / kg) standards t-r-r ·? '· / class (mg / kg) standards use in public. oracech (mg / kg S.3.) odor without match without wiring · without match / barza colorless colorless colorless - - - pH 7.3 5.4 6.0 - - - measures. odpcr (Ohm. cm) 4000 24000 45000 - - - OCO (mg 0 ₂ / l) 24 0 Q 240 <5000Í-> - COT (mg / l with £ with <* C <400 ^Í4) <1000

Elements the end a t r a o e (mg / l) v total quantity (mg / kg) extract. of gross. waste n o r m y (mg / kg) 1. extract 2.extract 3.extract tr · * • r 77 * ver. plowing (S.3.) lead 3.107 0.045 0.004 1.55 <100 <30 <4 cadmium NM NH NH - <50 <5 <1 zinc 3.23.5 0.095 0.264 7.17 <500 - - copper 2,274 th most common 0.611 0.056 29.41 - <20 <20 nickel 3,351 th most common 0.340 0.063 1.59 <100 - - chrome 3,363 th most common 0.000 0.000 0.50 <100 - <1 Quicksilver <3.302 <0.003 <0.003 <0.03 <10 <0.2 <0.2 cyanides NM NH NH - <10 - - arsenic 3.3Q42 0.0009 <0.0003 0.052 <10 <2 <2 chlorides 1.51 1.39 1.96 49.5 • <10000 <2300 sulphates 44 5 1 5QQ - - <4000

♦ corresponds to fly ash generated by incineration of municipal waste

NM »aeméřirelné, S.3. ³ dry matter (^ in mg / kg dry waste mg / kg gross waste

- 10 Table 4 - continued

Behavior on dissolution

- 11 -Andormalized leaching test table (check) ______ '

Slags from Salaise II (S II)

Analysis of extracts

3 ice variable i.extraction 2. extraction 3. extraction total amount of extract. from gross waste (mg / kg) standards r (D class :: < ² > (mg / kg) standards use in public. work (mg / kg S.3.) -odor without match without match without match baria yellowish colorless colorless - - - pH 6.3 7.1 7.6 - » - measures. resistance Q 900 3500 - O - (Ohm.ca) DCO 34 36 0 1200 <5000 ⁽¹⁾ - (mg Oj / i) CQT (mg / l 1 C £ C / · <400 ^(2> <1000

concentration (mg / l) v caik.quantity n o r a y (mg / kg) Elements i.extract 2.extract 3.extract (mg / kg) extract. from the count. waste u · 5. T class II * ver. plowing (S.3.) oiovo 0.443 0.115 0.052 6.li <100 <30 <4 cadmium 0.053 0.315 0.005 0.73 <50 <5 <1 zinc 0.093 0.329 0.028 1.50 <500 - - copper 0.088 0.055 0.034 1.33 - <20 <20 nickel 0.338 0.335 0.031 4.54 <100 - - chrome 0.100 0.000 0.000 1.00 <100 - <1 Quicksilver <0.003 <0.003 <0.003 <0.03 <10 <0.2 <0.2 cyanides NM NM NH - <10 - - arsenic 0.0008 0.0008 <0.0008 0.008 <10 <2 <2 chlorides 383.3 35.5 9.5 4333 - <10000 <2300 sulphates 1650 250 63 19530 - - <4000

* corresponds to Fly ash, created by burning municipal acetate

NM = not measurable, S.3. = dry matter í ^ in mg / kg dry waste ^) _in ng / kg gross waste

Table 5 - continued ____ Dissolution behavior

Elements r o z o u s t n or 3 t soluble amount in mg / kg gross. waste zero decreasing permanent growing in cond. test possibly dissolution (conc. waste) lead X 6.11 343 cadmium X 0.78 3.4 zinc X 1.50 948 copper X 1.88 14150 nickel X 4.54 1523 chrome X 1.00 20800 arsenic X 0.052 1092 chlorides X 4333 20500 sulphates X 19680 18200

- 13 Taboo Ika. 5 tTestrnoiaaliscvaného- leaching. (control). Slags from Saint-Vulbas (SV I)

Analysis of extracts

monitored size 1.extraction 2.extraction 3. extraction total amount of exrrah. from gross waste (mg / kg) , 1, trioa? * 'class 11.0) (mg / kg) ncuv use in cooking. work (mg / kg S.3.) odor without match without match without match color colorless colorless colorless - - - pH 9.64 9.36 8.5 - - - measures. resistance (Ohm.cn) 2222 5435 8695 • - - DCO (mg O2 / I) 4 0 0 40 <5000 ⁽¹⁾ - COT (mg / l NM 1 NM 10 <400 ⁽²⁾ <1000

concentration (mg / l) v aspen quantity n 0 r m y (mg / kg) Elements 1.extract 2.extract 3.extract (mg / kg) extract. from the count. waste three class II * ver. plowing (S.3.) lead 0.086 0.031 0.018 1.35 <100 <30 <4 Scarimi um 0.008 0.0028 0.0027 0.135 <50 <5 <1 zinc 0.010 0.003 0.0014 0.144 <500 - - copper 0.0024 0.0010 0.0007 0.041 - <20 <20 nickel 0.018 0.0084 0.0048 0.312 <100 - - chrome 0.027 0.0096 0.0077 0.443 <100 - <1 Quicksilver <0.003 <0.003 <0.003 <0.03 <10 <0.2 <0.2 cyanides NM NM NH - <10 - - arsenic 0.0008 0.0008 <0.0008 0.008 <10 <2 <2 chlorides 54.6 11.9 4.0 705 - <10000 <2800 sulphates - - - - - - <4000

♦ corresponds to fly ash generated by incineration of municipal waste NM - unmeasurable, S.a. - dry matter mg / kg dry waste ^ in mq / kg gross waste

- 14 -Table, i ..-, continued _________

Dissolution behavior

Elements dissolve n o s t soluble amount in mg / kg rake. waste zero decreasing permanent growing in cond. test possibly dissolution (conc. waste) lead X 1.35 190 cadmium X 0.135 1.3 zinc • X 0.144 620 copper X 0.041 3800 nickel X 0.312 784 chrome X 0.443 1205 chlorides X 705 -

Orientation in Tables 4, 5 and 6 will be facilitated by the following remarks, which relate to the four columns on the right-hand side of the lower parts of the abrasive bath:

the total amount extracted from the gross waste, expressed in mg / kg, corresponds to, for each element, ten times the sum of the amount released by the three extraction solutions (extractants) used to treat 100 g of this waste.

- these quantities are compared with the standards given in the three right-hand columns of the lower parts of the tables (and which correspond to the quantities given in the columns of French Standard Class I and French Standard Class II in Table 3 and standards used in public works in table 2).

these amounts are, in the continuation of the above tables, compared with the concentrations of the corresponding, potentially soluble elements, which do not differ from the values corresponding to the given slags and the contents given in Table I.

The following findings can be obtained from the analysis of Tables 4,5 and ó. regarding the possible nature of slag contamination, tested as an example. Samples ST 1, Sil and SV 1 provide leachates without color and odor. The chemical oxygen demand (IDCO), showing mineral and organic pollution, is 240 mg / kg for ST 1, 1200 mg / kg for Sil and 40 mg / kg for SV 1.

The soluble fraction of ST 1 slags (Table 4) can cause copper contamination (total amount released in mg / kg exceeds the class II standard and does not correspond to use in public works), zinc, nickel and chlorides (solubility in the obtained eluates increases).

When leaching Sil slags (Table 5), all measured elements showed decreasing solubility. However, their elution threshold exceeded the European standards for ordinary (not hazardous) wastes for lead (8.72 mg / kg dry waste), cadmium (1.11 mg / kg solid waste) in chromium (1.42 mg / kg dry waste) and 6.4 ml (6.48 mg / kg dry waste). Moreover, these extracts do not comply with the legislation governing the use of slag in public works (lead, cadmium, chromium and chlorides have too high threshold concentrations). The extracts nevertheless comply with French class II standards.

The extracts obtained from dried SV 1 slags comply with the above standards (Table 5).

It follows from the foregoing that some of the slag should be decontaminated before use, landfilling or backfilling. However, this would also be necessary in the case of SV 1 slags, which correspond to current standards, which, however, may not apply in the future.

The essence of the invention agrees to achieve inertization

The object of the invention is to provide a method which makes it possible to protect the environment by reducing the expensive storage of slags, in particular Class I landfills. The aim is, in particular, in the valid French and European standards, a very simple way of detoxification or slag, which can then be disposed of in Class II landfills with recycled waste.

as normal (not dangerous) or

According to a first basic aspect of the invention, the invention consists first in carrying out one or more extracts of slag, pre-crushed into sufficiently small particles, in particular up to 50 mm, in order to ensure sufficient contact between the combustion residues and the aqueous solvent or leaching liquid. It must have a sufficient concentration of cations (K *, Na ⁺ , Ca ²⁺ ) or exchangeable protons in the form of chlorides with heavy metal cations present in the said residues. This leaching must be sufficient to ensure the conversion of at least part of the metals to be determined, in particular the heavy metals contained in the slags, such as soluble chlorides, extractable with the leaching liquid, and to remove them successfully in a proportion sufficient to:

the standardized elution test of the last applied to the slag thus treated confirmed a decrease in the amount of each of the metals successfully dissolved during the re-extraction with the standardized leach solution, or elution in accordance with this test, and

- the sum of the amounts dissolved in the eluates obtained by extraction with the above-mentioned standard 1 with the isolated solution was in the range of values corresponding to concentrations lower than the threshold determined by the above-mentioned standardized test for each of the metals.

For accuracy, it was in the previous text and will be distinguished in the following test between:

"Evaporation solutions, ie extraction solutions containing the abovementioned cations or exchangeable protons and standardized elution solutions, corresponding to those used in the abovementioned standardized tests.

The number of elutions performed and the threshold concentrations (at least for metals already covered by a special standard) are specified in current or future standard 1 protocols. The standardization assay protocol used in the present text corresponds to the AFMOR test (X31210, 1988), the detailed procedure of which has been given above.

In the case of repeated elutions with standardized solution, it is used with at least a three-dimensional mixture and a demineralized stamp consists of demineralized water, saturated with air and CO2 at pH 4.5 and with a resistivity of 0.2 to 0.4 MO.cm.

Elutions with the standard solution are carried out by stirring the treated slag (eg in an amount of 100 g) with this solution for 16 hours.

The exchangeable cations or protons in the form of liquid chlorides used for the initial leaching of the slag can be in any form that allows to achieve the set goal. The leaching solution can be dilute hydrochloric acid, especially in the treatment of basic slags, which in aqueous suspension cause the formation of pH in the order of 9 to 10 in sufficient time. Slags under alkali metal or alkaline earth metal chloride solutions are used rather than hydrochloric acid under the same neutral conditions. . It is known from experience that even dilute hydrochloric acid excessively disrupts the inner mass or casing (tailings) of neutral slags. It is therefore the responsibility of the person skilled in the art to ensure that the concentrations of the cation exchange solutions in the form of chlorides and also the type of cations used (preferably potassium, calcium or other alkali or alkaline earth metal) are adjusted according to the slag used, according to the type of heavy metals released.

In general, the concentrations of hydrochloric acid in the acidic solutions used in accordance with the invention will range from 0.01 M to 1.0 M, while the concentrations of alkali metal or alkaline earth metal chlorides in the corresponding extracts will be limited to 0.01 M. , but rather from 0.05 M to 5 M.

As observed in experiments with different types of slag

ΙΜ, ΙΜ the hydrochloric acid solution is particularly suitable for treating basic slags and a 1 M solution of potassium t-tartaric acid or 0,01 M to 2 M, but in particular 0,09 M and 0 M A 15 M solution of calcium chloride allows the extraction of free metals contained in weak acid slags. Static or dynamic craving (slag / extractant ratio 1/1) will be followed by discharge of the extracts to the retention tank. Extracts may also be further modified as indicated.

Examples of embodiments of the invention

Example:

The slags from the incinerator in Strasbourg (ST 1) were crushed and sorted until a homogeneous average sample with a grain size of 0 to 2 mra was obtained. The slags from Saint - Vulbas (SV 1) were pre - dried before homogenization to an average sample. Slags from Salaise (Sil) were used as they were. Samples from Strasbourg (St 1), Salaise II (Sil) and Saint Vulbas (SV 1) showed pH values of 10.0, 7.6 and 8.2, respectively.

Experimental setup: extraction of exchangeable metals:

Extraction tests are performed using leaching tests of 100 g of slag in a closed column or dynamically (with stirring). The reagents used (100 ml per 100 g of slag) are 0.1 N hydrochloric acid, 1 M potassium chloride or 0.09 M and 0.15 M calcium chloride. They are left in contact with the slags for 2 to 24 hours and may be subject to two recycles (in order to achieve at least 3 times 24 hours of contact of the slags with the extraction liquid). The pH, conductivity and chemical composition of the obtained extracts are determined. After washing the slag sample twice with 100 ml of distilled water, a normal leaching test was performed.

Results:

The extractants used in the mobility test produced soluble metal chlorides with the slag elements, the rate of formation of which is a function of their solubility constant.

Potassium chloride (1M) solubility of calcium and copper (excess reagent) and sodium, bath, were tested in its mass and, for example, induced considerable in ST 1 slags. Potassium both did not show plasma staining as essential elements in this experiment).

In the course of the process, the soluble elements of the analysis had a negative effect on yellow (yellow are listed in Table 7. In the slags of Sil were the most easily released main elements magnesium and manganese, trace elements were soluble in various proportions (Table 7). , an analytical failure caused by the strong solubility of alkaline earth elements was also noted.

Hydrochloric acid mobilized metals, especially copper, more efficiently in ST 1 slags. However, the dissolution of alkaline earths with hydrochloric acid caused an error in the determination of calcium, while the yellow color of the plasma indicates the strong presence of sodium (Table 7).

Table 7: Determination of mobility of 9 main elements and 7 trace elements

-------- metal number - * T azž e η ί T00 g ~ ^ 'slags ~ after ripples' 100 nr I --------- extractant on a closed column ( 3 completed passages). The analysis of the extracts was performed by determining the metal elements in the solution by means of plasma emission spectrophotometry. The results are expressed as a percentage by weight of the original content.

Determined elements elements extracted (v ϊ) M KC1 elements extracted (in%) 0.1 ř HCl slag ST 1 slag S II slag ST 1 slag S II aluminium 0.00 0.00 0.33 0.01 calcium 0.05 0.00 immeasurable you don't measure flax manganese 0.00 0.14 0.41 0.60 magnesium 0.01 1.05 0.64 5.45 iron 0.00 0.00 0.17 0.00 silicon 0.00 0.00 0, .19 0.01 potassium immeasurable immeasurable not specified not specified sodium not specified not specified not specified not specified phosphorus not specified not specified not specified not specified cobalt 0.00 0.19 0.02 0.59 chrome 0.00 0.03 0.00 0.04 copper 0.02 0.00 10.10 0.00 nickel 0.00 0.04 0.08 0.32 z inek 0.00 0.01 0.13 0.04 cadmium 0.00 0.00 0.00 0.00 lead 0.00 0.18 0.49 0.23 i

Table 8: Determination of the mobility of 9 main elements and 7 trace metals during the washing (2 x 100 ml of distilled water) 100 g of slag on a closed column after curing with 100 ml of extractant. The analysis of the washing water was performed by determining the metallic elements in the solution by plasma emission spectrophotometry. The results are expressed as a percentage by weight relative to the original content.

Determined elements elements extracted (in M KC1 elements extracted (in%) 0.1 N HCl slag ST 1 slag S II slag ST 1 slag S II aluminium 0.00 0.00 0.01 1 I 0.00 calcium 0.00 0.00 0.01 even immeasurable manganese 0.00 0.02 0.01 | 0.23 magnesium 0.00 O, 05 0.64 0.51 iron 0.00 0.00 0.00 0.00 silicon 0.00 0.01 0.01 0.01 potassium unmeasurable immeasurable not specified not specified sodium not specified not specified not specified not specified phosphorus not specified not specified not specified not specified cobalt not specified not specified not specified not specified chrome not specified not specified not specified not specified copper 0.00 0.00 0.59 0.00 nickel 0.00 0.01 0.01 0.11 zinc 0.00 0.01 0.07 0.02 cadmium 0.00 0.00 0.00 0.00 lead 0.04 0.14 0.07 0.19

Washing with water is intended to remove excess reagents before testing. The test of the r-Behenr-tuIto-feo test showed only poor mobility of the element, independent of the extractant and the type of slag used (Table 8).

The percentage of metals releasable from the slag could not be accurately determined, but partial analyzes performed during the passage of the reagents indicated that even contact between the slag and the extractant for 2 to 24 hours and a single wash would be sufficient to effectively stabilize the waste. This simplification by limiting the number of steps originally envisaged shows the importance of one leaching and optimizes the process.

Normalized leaching test

Given the purpose of these examples, leaching tests must comply with French Class 2 standards, non-hazardous European waste standards and standards for the use of slag for public washing.

After two procedures to which the slags from Strasbourg (ST 1) and Salaise (Sil) were subjected, the standardized tests are aimed at obtaining extracts with increased specific resistance to control, ie to obtain wastewater with lower mineral content (Figures 1 and 2).

A reduction in chemical oxygen demand (DCO) of 23% was observed after the use of potassium chloride in Salaise II (Sil) slag and by 100% after all other treatments regardless of the type of slag (Figure 3).

Figures 1 and 2, relating to standard 1 of the leaching test for slag leaching from Strasbourg (ST) and Salaise II (Sil), show the difference in the resistivity of the extracts before and after the application of the leaching fluid, where the resistivity was measured after measurement. Testu í of the called test (frames ~ AFNOHX 31210, —1988 -) - expressed in ohms per cm on the y-axis (ordinates)

- for slag in its original state

- for slags pretreated with potassium chloride solution (KC1) and for slags pretreated with hydrochloric acid solution (HCl).

Figure 3 shows the decrease in DCO (S DCO on the y-axis of the graph) caused by the treatment of slags from Strasbourg (ST 1) and from · Salaise (Sil).

For contaminating metallic elements, chlorides and cyanides, standards require their decreasing solubility or solubility threshold. The determination of these parameters for strongly alkaline slags from Strasbourg (ST 1) yielded the following results:

- the effect of the potassium chloride solution was manifested by a strong release of polluting metals; At the same time, several metals (lead, copper and chromium), as well as chlorides, showed increasing solubility (Table 9) and the effect of hydrochloric acid (Table 10) on accentuating the solubility of pollutants, but the prescribed elution threshold and declining solubility trend remained consistent. with French and European standards for non-hazardous waste. Adequate slag formation would be usable for public works.

Tables 11 and 12 present the results obtained under similar conditions, in the tests of standardized leaching after treatment of Sil slags with potassium chloride (Table 11) and hydrochloric acid (Table 12).

- 25 Table 3: Normalized leaching test after SCI treatment

Stnsky of Strasbourg (ST 1)

Extraction analysis

slsdcwi vel / érna L.extraction 2. extraction 3. extraction total amount of extract. from gross waste (mg / kg) 20 ΓΖ7 class l ' ¹ »class :: ⁽²⁾ (mg / kg) standards use in public. work (mg / kg S.3.) odor without match without match without match • • - color colorless colorless colorless - - - p2 7.0 5.4 5.0 - - - measures. cdpcr (Ohm. cm) 30000 45000 50000 - - DCO (mg Oj / l) 0 0 0 240 <5000 ⁽¹⁾ - COT [mg / l E 5 6 C <400 ^ <1000

concentration (mg / l) v total quantity η · o r m y (mg / kg) Przky 1. extract 2. extract 3.extract (mg / kg) extract. of gross. waste three ver. Draci (S.a.) lead 0.044 0.001 0.014 0.59 <100 <30 <4 cadmium SH SH. SM - <50 <5 <1 zinc 0.282 0.293 0.278 8.53 <500 - - copper 0.575 0.1: 0 0.239 10.55 - <20 <20 nickel 0.052 0.031 1.14 1.59 <100 - - chrome 0.060 0.000 0.000 0.50 <100 - <1 Quicksilver <0.003 <0.003 <0.003 ' <0.03 <10 <0.2 <0.2 cyanides SM SH. SH - <10 - - arsenic 0.0009 0.0003 <0.0003 0.009 <10 <2 <2 chlorides 0.3 2.33 0.52 37.5 - <10000 <2800 sulphates 1.4 2.2 <1.0 36.0 - - <4000

* corresponds to fly ash, generated by incineration of municipal waste SH = unmeasurable, S.3. = dry matter ag / kg dry waste ag / kg gross waste

- 26 Table 9 - continued

-----— Behavior before dissolution _______________________

Elements r o z d u s t and o s t soluble amount in mg / kg gross. waste zero decreasing permanent growing in cond. test possibly dissolution (conc. waste) lead X 0.59 186 zinc X 8.53 1900 copper X 10.65 4800 nickel X 0.312 5800 chrome X 0.60 20800 arsenic X 0.009 6.2 chlorides X 37.5 3990 sulphates X 36.0 300

- 27 Table 10: Normalized leaching test after treatment in the presence of 3CI ____________________ Slag-from Strasbourg-fST-l) ------------------------ Analysis of extracts

monitored size 1.extraction 2. extraction 3. extraction total amount of extran. from gross waste (mg / kg) nonv., class * 14 class il < ² > (mg / kgj standards used to believe. oracech (mg / kg S.3.í J ZápaC ” without match without match; ' without match color colorless colorless colorless - - - Bye 7.0 6.4 6.0 - - - measures. resistance (Ohm.cm) 70000 30000 90000 • • DCO (mg O ₂ / l) 0 0 0 0 <5000 ⁽¹⁾ COT (mg / l 5 £ << · <400 ^(ί> <1000

concentration (mg / l) v aspen quantity n 0 r m y (mg / kg) Elements 1.extract 2. extract 3.extract (mg / kg) extract. from the grave. waste three class II * ver. oracl (S.3.) lead 0.07544 • 0.329 0.015 1.19 <100 <30 <4 cadmium NM NM NM - <50 <5 <1 zinc 0.132 0.370 0.043 2.5 <500 - - copper 0.723 0.295 0.197 '12.15 - <29 <20 nickel 0.064 0.04531 0.041 1.50 <100 - - - chrome 0.040 0.000 0.000 0.04 <100 - <1 Quicksilver <0.003 <0.003 <0.003 <0.03 <10 <0.2 <0.2 cyanides NM NH NM - <10 - arsenic 0.0071 0.3025 <0.0008 0.096 <10 <2 <2 chlorides 5.92 1.05 1.00 79.7 - <10000 <2300 sulphates 24 2.4 1.2 276 - - <4000

* corresponds to fly ash, generated by incineration of municipal waste

NM = not measurable, S.3. - dry matter ^ ’in mg / kg dry waste ^ in ag / kg gross waste

- 28 Table 10 - continued

-------------- Behavior at. dissolved --------

Elements razDUstnost Dissolved affinity zero decreasing permanent growing in ao / kg game . waste in hand. test pria. dissolution (conc. waste) lead X 1.19 135 zinc X 2.50 1900 aed X • 12.15 4300 nickel X 1.50 ' 5300 chrca X 0.04 20300 arsenic X 0.095 5.2 chlorides X 79.7 3990 sulphates X 275 300

- 29 .Table. lU-lest-n & raaiisované-lužení po- uprava- za. presence of KC1.

Slags from Salais II (S II)

Analysis of extracts

malted vaL’č’oa l.axcrakca 2. extraction 3. extraction total quantity extracted. from gross waste (mg / kg) normv class class ií < ² ! (mg / kg) standards use in cooking. oracech (ng / kg S.3.) odor without match haz zap. without match bara colorless colorless colorless - - - pH 7.1 7.1 7.2 - - measures. cdnor 900 2600 6000 - - (Ohm. And DCO 20 8 . 0 280 ' <50Q0 ⁽¹⁾ (mg 0 ₂ / I) COT (mg / 1 C C 6 with <400 ⁽²⁾ <1000

the end a t z a o e (mg / l) v total quantity n o r m y (mg / kg) Elements 1.extract 2.extract 3.extract (mg / kg) extract. of gross. waste ci.Z class II ¹ cook. Dragons (S.3.) lead 0.181 0.35 0.024 2.55. <100 <30 <4 cadmium 0.023 0.303 0.004 0.35 <50 <5 <I zinc 0.037 0.317 0.011 0.55 <500 - - copper 0.045 0.325 0.014 0.95 - <-20 <20 ' nickel 0.139 0.353 0.028 2.20 <100 - - chrome 0.060 0.300 0.000 0.50 <100 - <1 Quicksilver <0.003 <0.303 <0.003 <0.03 <10 <0.2 <0.2 cyanides NM NM NM - <10 - - arsenic 0.0008 0.3008 <0.0008 0.008 · - • <10 / <2 <2 chlorides 127.0 17.3 3.2 1472 - <10000 <2800 sulphates - - - - - - <4000

* corresponds to fly ash, generated by incineration of municipal waste

NM = aemeral, S.3. = dry matter (^ in ag / kg dry waste ^ in mg / kg gross waste

- 30 Table 11 - continued

Dissolution behavior

Elements solubility soluble amount in mg / kg gross. waste zero decreasing permanent growing in cond. test possibly dissolution (conc. waste) lead X 2.65 343 cadmium X 0.35 3.4 zinc X 0.55 943 copper X 0.95 1450 nickel X 2.20 1523 chrome X 0.60 1092 chlorides X 1472 20500

______________Apple 12; Normalized leaching test after treatment in the presence of SCI

Slag zs Saíaisa II (S II)

Extract analysis

monitored size 1.extraction 2.extraction 3. extraction total amount of extract. from gross waste (mg / kg) standards. 5Ϊ ii ^ i (mg / kg) standards use in public. oracach (mg / kg S.2.) - · · - = odor without match without match without match · «, - color colorless colorless colorless - - - pH 6.8 6.5. 7.0 - measures. resistance 1000 3000 6000 - - (Ohm.ca) DCO 0 0 0 0 <50C0 ⁽¹⁾ - (mg Oj / l) COT (mg / l C C of <400 ⁽²⁾ <1000

Elements concentration (mg / l) v total quantity (mg / kg) extract. of gross. waste standards (mg / kg) 1.extract 2.extract 3.extract class I class II * ver. plowing (S.3.) lead ifannti um zinc copper nickel chrome Quicksilver cyanides arsenic chlorides sulphates 0.421 0.056 0.118 0.371 0.913 0.020. <0.003 NM 0.0008 33.3 0.155 0.020 0.044 0.043 0.253 0.010 <0.002 NH 0.0003 17.2. 0.053 0.007 0.033 0.023 0.122 0.000 <0.003 NH <0.3008 7.3 5.35 0.33 2.00 1.42 12.94 0.30 <0.03 0.008 58 <100 <30. <4 <50 <5 <1 <500. . -. <20 <20 <100 - - <100 <1 . <10 <3.2 <0.2 <10 <10 <2 <2 - <10000 <2800 <4000.

* corresponds to fly ash, generated by incineration of municipal waste

NH = not measurable, S.3. ³ dry matter t ^ in mg / kg dry waste ^) _in ng / kg gross waste

- 32 Table 12 - continued

......... Ch Dissolution behavior-

Elements r o Z p U 3 t nose t soluble amount in mg / kg gross. waste zero decreasing permanent growing in cond. test possibly dissolution (conc. waste) lead X 6.35 343 cadmium X 0.83 3.4 'zinc X 2.00 948 copper X 1.42 1450 nickel X 0.30 1523 chrome X 0.60 1092 chlorides X 583 20500

Conclusions:

1) provide without prior which 'exceed French

With regard to the tests performed on the leaching of slags and their possible storage in class II or their recycling, the following conclusions can be drawn from previous experiments dealing with the treatment of slags or their inertisation according to the AFNOR determination protocol:

Strasbourg slags (ST treatment of eluates with toxicity thresholds, Class II standards (in addition to European standards)) These eluates also do not comply with the regulations governing the use of slags for public works. as European standards for non-toxic waste and treated slag will also be able to be recycled in public works.

Salaise II (S II) slags provide, without pre-treatment, eluates with toxicity thresholds lower than those required by the French standards for Class II but higher than those required by European standards for non-toxic waste and standards for use in public works. After treatment of the slags with potassium chloride, the resulting eluates are in accordance with European standards and standards for slag recycling.

The leachates from the leaching process contain metal chloride salts as well as an excess of extractant. The average composition of the extracts and washing waters, combined after all stages of treatment of 100 g of slag, is given in Table 14.

- 34 Table 13: Overview of the result obtained during slag treatment. Comparison of the result of their leaching with European and French standards for landfilling. Threshold concentrations refer to the leachable fraction obtained in the case of European standards by the German test (10Qg dry waste / 1 l of water) and in the case of French standards by the AFNOR test (10Qg of gross waste / 1 1 vcdv). The results are given as a soluble amount in mg / kg.

and hazardous waste C32 mg / kg '** French standards class I (slag) mg / kg ' ² * ordinary waste of standard C ^ Z mg / kg *** franc.normy cl. II (flying field) mg / kg ^ ² ' inert waste of the Czech Republic standard mg / kg * ¹ * standards used for ver. oracam mg / kg ^ ** Bye. 4 - 13 5 - 13 4 - 13 4 - 13 - DCO - <5000 - - - - loss annealing - <S i - - - <5 ϊ COT 400-2000 - 400-2000 <400 <2000 <1000 arsenic III 2 - 10 <10 1 - 2 <2 <1 <2 lead 4 - 20 <100 <4 <30 total <4 Ifarimi nm 1 - 5 <50 <1 <5 content <1 chrome VI 1 - 5 <100 <1 - these <1 copper 20 - 100 - <20 <20 przků <20 nickel 4 - 20 <100 <4 - must - Quicksilver 0.2 - 1 <10 <0.2 <0.2 be <0.2 zinc 20 - 100 <500 <20 - <50 mg / kg • J

in mg / kg dry waste xg / kg gross waste

- 35 Table 13 - Dreaction

slag. ST Z ³ ac / ko ' ^z ' jcruaky 37 Z bs ¹ * Ιζγι'γζ before editing by SCI hooks before editing 30 ICI hooks 32 5.5 7.0 7.1 7.1 about what 240 0 1200 230 40 annealing C - = . 13.35 - 12.55 • COT j * C / · 10 arsenic ZZZ 0.352 0.096 <0.003 <0.003 <0.302 lead 1.55 1.19 5.11 (8.72) 2.55 (3.73) 1,250 th most common cadmium 0.00 0.00 0.73 (1.11) 0.35 (0.50) 0.135 chrome 7Z 0.50 0.34 1.00 (1.42) 0.50 (0.35) 0.442 aéd 29.41 12.15 1.38 (2.53) 3.35 (1.35) 3,341 th most common nickel 1.59 1.50 4.54 (5.43) 2.20 (3.14) 3,212 th most common ruut <0.03 <0.33 <0.03 (<0.03) 3.33 (<0.32) <3.33 zinc phenols - - - - - fluor - - - - - amcniua - - - - - chlorides 49.5 79.7 4333 (5190) 1472 (2102) 705 cyanides - - - - sulphates 500 275 19530 - •

^ in nc / kg dry waste and g / kg gross waste

3.5 humidity <1 í humidity 30 i

- 36 Table 13 - continued

hazardous waste nony CEE mg / kg ' ¹ ' French standard weight (slag) mg / kg ' ² ' common waste of CEE standard mg / kgl ¹ ' franč.normy cl. II (fly ash! Mg / kg ' ² ' inert wastes of C2E standard mg / kg standards of use for ver. working mg / kg ' phenols 200-1000 100 - 200 <100 fluor 100-500 • 50 - 100 - <50 - ammonium 2 - 10 2 - <500 - chlorides 12000-60000 5000-12000 <10000 <5000 <2800 cyanides 2 - 10 1 - 2 - <1 - sulphates 2000-10000 2000-10000 - <10000 <4000 nitrite 50 - 300 30 - 60 - <30 - AOX 5 - 30 3 - 6 - <3 - chlorine. solvent. 0.2 - 1 0.1 - 0.2 - <0.1 - chlorine. pesticides 0.01-0.05 - 0.005-0.01 - <0.05 - lipophilic substances 4 - 2Q * 4 - 10 • <10 *

(·) In mg / kg dry waste in mg / kg gross waste ³ ' ⁵ humidity <1 1 * humidity 30 1

- 37 —Table

-14 -: - C hem i e ká — ana.1 ys.a leachates ___ a__pr rinsing ,, X-OJL

Average composition, measured after several stages of slag treatment from Strasbourg (STÍ) and Salaise II (S II).

EXTRACTS WASHING WATERS pH 1.86 to 9.37 4.30 to 8.94

concentration (rag / 1) concentration (mg / i) aluminium 0.4 to 170 0.09 to 3.06 iron 0.5 to 415 0.06 to 10.78 magnesium 1.4 and b 288 0.12 to 27.76 manganese 0.02 to 60 0.03 to 20.52 silicon 2.6 to 256 9 calcium 9 9 s od í k 9 9 copper 0.1 to 484 0.08 to 28.44 z inek 0.04 to 2.4 0.05 az 1.26 lead 0.6 to 0.9 0.07 and b 0.60 nickel 0.6 and b 4.7 0.02 to 1.56 chrome 0.3 to 0.5 - cobalt 0.18 to 1.21 - cadmium 0 0

Leaching involved other reagents under different conditions.

------— The conversion of s / trus-ek — to -erer-tn-í- and ter-th t — examines the exchange of exchangeable cations or protons. Research has focused on the possibility of using salt and acid waste from incinerators up to the reaction ends.

Experimental extraction setup

The leaching was carried out in 2 l flasks with constant stirring (dynamic leaching) of 1 l of extractant and 100 g of slag. Based on preliminary experience, the incubation was run for 2 hours at room temperature. The procedure was terminated by washing with 1 L of distilled water. The solid and liquid phases were separated by centrifugation at 2000 g and filtration on a 0.45 (μm) Millipore membrane was used for analytical purposes.

Treatment of salt residues of slags resulting from the incineration of chlorinated wastes

Dynamic leaching of Sil slag; extracts and washing waters

Sil slags were leached using Rhona wastewater from the TREDI Saint-Vulbas (Ain) center; this extractant corresponds to the current sampling carried out in January 1992 at the mouth of the treatment plant (Table 15).

Sil slags were also extracted with the prepared calcium effluent (calcium chloride at a concentration of 10 g / l, corresponding to a molar concentration of 0.09 M) and further leached with 1 M potassium chloride.

Results

The use of salt wastes in accordance with the regulations for extraction reagents has led to a considerable reduction in the elution threshold in comparison with cantro-Lo-U (Table 16). T£ mtp_dy.namLckým-l-o-už@Mía was mainly released nickel. Chromium, despite abundant in waste, remained insoluble. The DCO did not change while the COT decreased by 50 X, due to the adsorption of organic matter on the slag (Table 17).

The use of the prepared calcium effluent resulted in similar results under the same conditions (Table 18).

The use of potassium chloride caused lower nickel extraction and more efficient copper release (Table 19).

The wash waters eliminated residual soluble elements in all procedures and removed excess reagents (Tables 17 to 19).

Proof of slag stability

Salaise II slags, leached with saline wastes or prepared calcium effluent, show a decrease in the soluble fraction, which allows their use for public washing. The DCO of the extracts is reduced as well as the solubility of the chlorides and also the content of sulphates reaches lower concentrations than the threshold values set by the standard for public works (modified in 1992). Decreasing nickel solubility is also guaranteed (Tables 20 and 21).

Salaise II slags, leached with 1 M KC1, show, as in the previous case, sulphide concentrations, allowing use in public works (Table 22).

The treatment of slags by leaching brings in all cases, thanks to the removal of the polluting fraction, a clear increase in the specific resistance of the extracts of the standard of the pressed test.

_______ 2 _____ The foregoing — it follows that both potassium and calcium chloride allow significant release of heavy metals from the slag, although the observed ratios will be different. In each case, it will be the task of the person skilled in the art to select a suitable salt for successful leaching according to the composition and extractability of the slag with the different heavy metal cations whose inertization is required. It is clear that calcium chloride often stabilizes the treated slag.

For various slags, it was observed that the amount of calculated exchange capacity exceeds the content of heavy metals, especially the exchanged cation and Sil slag, calcium was exceeded this amount additionally extracted during leaching.

The treated slags improve the quality of their soluble fraction, the solubility of nickel, chlorides and sulphates 18 months after sampling (Table 20).

This test, repeated with slags stored under the action of calcium chloride [loss of soluble fraction and chlorides and sulphates (Table 2 performed after 3 months at normal temperature), shows that they have stabilized, in particular a decrease in the elution threshold.

There was also no destabilization of the inner mass of the slag. The observed stability could be explained to us in passing.

Mineral analysis of Sil slags, carried out under the same control conditions as for the monitored sample 3 months after the leaching, showed that the slags treated in the presence of calcium were enriched with carbonates. The control slag sample contained 1.83% carbon in the form of carbonates while the treated slag sample contained 2.83%, an increase of

30 -% content of -uh-ti or ta rtu ---------------------------------- Calcium exchange during leaching would therefore make it possible to accelerate the natural carbonisation of the slags, which will increase their stability. Such a result is of particular importance, for example, in the case of slags from municipal waste incinerators, which are only moderately leachable and are stored in the open air for a long time.

Table 15: Composition of waste water discharged to Rhónv from the TREDI Saint-Vulbas center. The analysis was determined on January 13, 1992, either by plasma emission spectrometry or by atomic absorption.

s iced in 1ič ina Rhone wastewater pH 7.6 measures. resistance (Q.cm) - DCO (mg Oz / 1) 750 COT (mg / 1) 13

elements concentration (mg / l) * lead <0.010 (0.000) cadmium <0.010 (0.000) zinc 0.120 copper 0.180 nickel 0.120 chrome <0.010 (0.003) calcium 2030 chlorides 3540

detection limits and (raw data)

- 42 Table15r Slags from- Salaise (5- lij -----------

physical character. waste results Class I standards * standards class II ** standards used for ver. plowman (V.?.) soluble fraction (dry waste) 4.5i <101 <51 <31 annealing losses (dry at 550 ° C) - <51 - <51 CT (dry) - - - - Bye 7. « 4 <pH <13 - - dryness 73.5% > 351 • -

¹¹ refers to standards for slag before stabilization ** applies to fly ash generated by incineration of municipal waste

monitored size leachate 1.extract 2.extract 3.extract total amount: extr. from gross waste (mg / kg) standards class I '* * class 11 () (mg / kg) ceik. amount of dry waste extr. (mg / kg) standards 71? '.' for dry answer (mg / kg) odor without match without match without match color yellowish colorless colorless - - - - pH 5.3 7.1 7.5 - - - - measures. resistance (Ohm.cm) 0 900 3500 - - - - OCO (mg O ₂ / l) 34 35 0 1200 <5000 ⁽¹ ) 1530 - COT (mg / I) <1 <1 <1 <30 <10 ⁴ < ¹ > / <400 ( ²⁾ <41 <1500 volume (1) 1,000 1,000 1,000 - - - -

(D _in mg / kg dry waste ^ in mg / kg gross waste

- 43 .Table 16 - continued

concentration (mg / l) v total quantity n o tav caik. quantity standards Slings 1.extract 2.extract 3.extract (mg / kg) extract. from the count. waste rr · .. extr.ze such. waste (mg / kg IN P. for such.cáp. (mg / kg) oirao 0.443 0.115 0.052 6.11 <100 <33 3.30 <15 cadmium 0.053 0.015 .. <0.010 . 0.73-0.83 <50 <5 0.99-1.13 <1 zinc 0.093 <0.050 <0.050 0.93-1.93 <500 - 1.25-2.52 - copper 0.038 0.065 <0.050 1.54-2.04 - <20 2.10-2.77 - nickel 0.333 0.085 <0.050 4.23-4.73 <100 - 5.74-5.42 - chrome 0.100 <0.010 <0.010 1.00-1.20 <100 - 1.35-1.53 <1 Quicksilver <0.001 <0.001 <0.001 <0.03 <10 <0.2 <0.04 <0.2 cyanides NM NM NM - <10 - - - 3X52 « <0.010 <0.010 <0.010 <0.30 <10 <2 <0.40 <2 chloride'; 338 85 9 4330 - <10002 5383 - sulphates 1530 250 63 19630 - - 25739 <7000

NM: unmeasurable

Dissolution behavior

Slings solubility soluble amount of rake. waste in conditions test (mg / kg) amount possibly soluble (total co-concentration of dry waste) 1mg / kg) zero decreasing permanent growing lead X 5.11 343 cadmium X 0.73-0.33 '3 zinc X 0.93-1.93 948 copper X 1.54-2.04 14150 niki X 4.23-4.73 1523 chrome X 1.00-1.20 1092 chlorides X 4330 20500 sulphates X 19680 13200

- 44 T abu tk a — 17 -: - Sta new π v ve ~ výl už £ č h ^- á prb mý v ąch ~~ v vá v - v e-e e e t e »treatment of slags from Salaise II (Sil) with wastewater from Rhône.

sedated quantity extracts washing water PH 7.5 7.1 measures. resistance (Q.cm) 94 925 DCO (mg O / l) 414 0 COT (mg / 1) 6 7 elements concentration (mg / l) * lead <0.010 (0.000) <0.010 (0.000) cadmium 0.012 <0.010 (0.000) zinc 0.60 <0.05 (-) copper 0.200 <0.50 (-) nickel 0.850 0.120 chrome <0.010 (0.000) <0.010 (0.000) calcium 1930 150 chlorides 3940 250

detection limits and (raw data)

Table -18 Determination of leachates and washing of defects during the treatment of Salaise II (Sil) slags with CaCl 2 at 10 g / l.

s 1 edited quantity extracts washing water PH 7.2 7.5 measures. resistance (Ω.cm) 86 1030 DCO (mg O2 / I) 407 35 COT (rag / 1) 5 6 elements concentration (mg / l) * lead 0.010 (0.009) <0.010 (0.001) cadmium 0.011 <0.010 (0.000) zinc <0.060 <0.050 (0.010) copper 0.150 <0.050 (0.030) nickel 0.710 0.100 (0.060 chrome <0.010 (0.001) <0.010 (0.000) calcium 2580 171 chlorides 4925 300

detection limits and (raw data)

T.a h ulka_ 19: Establishment -v e výT uses e-h — a — the average in water during the treatment of Salaise II (Sil) 1 M KC1 slag.

monitored quantity extracts washing water PH 7.8 7.4 measures. resistance (Q.cra) satur. 107 DCO (mg 02/1) 3934 171 COT (mg / 1) 4 3 elements concentration (mg / l) * lead 0.014 <0.010 (0.002) cadmium 0.032 <0.010 (0.000) zinc <0.050 (0.030) <0.050 (0.010) copper 0.210 <0.050 (0.010) nickel 0.390 0.100 (0.080) chrome <0.010 (0.002) <0.010 (0.002) calcium 173 15 chlorides 25400 1770

detection limits and (raw data)

- 47 Table 20: Test of normalizedhqj.pužení_co, treatment, pcmoci.uxipadni-vcdy-3hany, - rinsing of Slag from Salaise II (S II)

physical character. waste results Class I standards * Class II standards * » standards of use for ver. plowman (V.?.) soluble fraction (dry waste) í.n <101 <51 <31 . annealing losses (dry at 550 ° C) <51 - <5 i COT (dry) - - - - pH 8.5 4 <p3 <13 - - dryness 63.9% > 35% - -

* refers to standards for slag before stabilization ** applies to fly ash generated by incineration of municipal waste

Analysis of extracts

monitored size leachate 1.extract 2.extract 3.extract total amount of extr. from gross waste (mg / kg) normv, class OO class II0 (mg / kg) total. amount of dry waste extr. (mg / kg) standards 7.?. for dry answer (mg / kg) odor without match without match without match color colorless colorless colorless - - - - pH 6.9 7.3 7.7 - - - - more. resistance 1110 3540 5130 • - • • (Ohm.cm) DCO 0 0 0 0 <5000 (4 0 (mg O ₂ / l) COT (mg / L) 11 5 5 218 <1 0 ⁴ (4 / <40θ ( ² ) 341 <1500 volume (1) 1,000 1,000 1,000 - - -

(D _in mg / kg dry waste)

- 48 -Tableuline ^^ - continued

concentration (mg / l) v total quantity n o r a v ceifc. anczs :. ncray Elements 1.extract 2.extract 3.extract (mg / kg) extract. of gross. waste three cl extr.ze such. cdpad (ag / kg) 7.P. pr: such.cdp. (ag / kg) lead <3.010 <0.010 <0.310 <0.30 <100 <30 <0.47 <13 cadmium <0.010 <0.010 <0.010 <0.30 <50 <5 <0.47 <1 •zinc <0.050 <0.050 <0.050 <1.50 <500 - <2.35 - copper 0.050 <0.050 <0.050 0.60-Í.5Q - <20 0.94-2.50 - nickel 0.160 <0.050 <0.050 1.50-2.60 <100 - 2.50-4.00 · - chrome <0.010 <0.010 <0.010 <0.30 <100 - <0.47 <1 Quicksilver <0.001 <0.001 <0.301 <0.03 <10 <0.2 <0.04 <0.2 cyanides NH NH NH - <10 - - - arsenic <0.010 <0.010 <0.310 <0.30 <10 <2 <0.47 <2 chlorides 39 9 4 720 - <10000 1127 - sulphates 325 81 38 1 4450 - 5953 <7000

NH: unmeasurable

Dissolution behavior

Elements ro zo us t no s t resettable amount 'arub. waste in conditions test (mg / fcg) quantity or soluble (total dry waste concentration) (mg / fcg) zero decreasing permanent growing aed 1 0.60-1.50 13874 nickel Ϊ 1.60-2.50 1463 chlorides n 720 20500 sulphates X 4450 18200

- 49 Table 21: Nora test. The mixture was prepared by means of a prepared mixture (CaCl.-á_XQ_a / I) with constant stirring of the slag from Salaiss II (S II).

physical character. waste results Class I standards * class 11 standards ** standards of use for ver. plowman (V.?.) soluble fraction (dry waste) 1.4? <10% <51 <31 annealing losses (dry at 550 ° C) - <si - <51 COT (dry) - - - - pH 7.3 4 <pH <13 - - dryness 55.71 > 35% - -

* refers to pr: slag standards before stabilization ”refers to flying pcpiiek generated by municipal waste incineration

Analysis of extracts

monitored size leachate 1.extract 2.extract 3.extract total amount of extr. from gross waste (mg / kg) normv, - (i) class II (mg / kg) ceik. amount of dry cdpad extrusion (mg / kg) ncrmy V.?, For dry answer (mg / kg) odor without match without match without match • color colorless colorless colorless - - - - pS 7.3 * * 1.0 7.3 - - * - measures. resistance (Ohm.ca) 1130 3420 6210 - - - - DCO (mg O ₂ / I) 0 and 0 70 <5000 ⁽¹⁾ 105 - COT (mg / 1) 9 5 4 180 <Ι0 ⁴ < ¹ > / <400 < ² > 270 <1500 volume (1) 1,000 1,000 1,000 - - - -

mg / kg of dry waste ^) ₇ mg / kg of gross waste

- 50 ------ Tabttlka-Ti - ^ - ooicKScnrání

concentration (mg / l) v total quantity n o r a y total. anožst. ncrzy Elements 1.extract 2.extract 3.extract (mg / kg) extract. of gross. waste three class II extr.ze such. waste (ag / kcj 7.?. for 3 * ^ dw · (ac / kc) lead <0.010 <0.010 <0.010 <0.30 <100 <30 <0.45 <1: cadmium <0.010 <0.010 <0.010 <0.30 <50 <5 <0.45 <1 zinc <0.050 <0.050 <0.050 <1.50 <500 - <2.25 - copper <0.050 <0.050 <0.050 <1.50 - <20 <2.25 - nickel 0.150 <0.050 <0.050 2.10-2.50 <100 - 3.14-3.90 - chrome <0.010 <0.010 <0.010 <0.30 <100 - <0.45 <1 Quicksilver <0.001 <0.001 <0.001 <0.03 <10 <0.2 <0.04 <0.2 cyanides NM NH NM - <10 - - - arsenic <0.010 <0.010 <0.010 <0.30 <10 <2 <0.45 <2 chlorides 101 13 5 1190 - <10000 1733 - sulphates 290 32 39 4110 - - 5159 <7000

NM: unmeasurable

Dissolution behavior

Elements solubility soluble anosity coarse. waste in conditions test (mg / kg) anozství optionally. soluble (total dry waste concentration) (mg / kg) - zero decreasing permanent growing nickel X 2.10-2.50 1453 chlorides X 1190 20500 sulphates X 4110 13200

- 51 —- τ & ώΒ'22: 'Test nonalísdvacéhd' louženroo-upravé 'aid? JGl-for mixing --------------- Roofs of Salaise II (S II)

physical character. waste results Class I standards * Class II standards standards of use for cooking. plowman (V · ?.) dissolved fraction (dry waste) 1.5) .. WHAT) <5 5 <3) annealing losses (dry at 55 ° C) - <5! - <5) COT (dry) - - - - he it 7.3 4 <p3 <13 - - vyschlcst 53.2% > 35) -

* refers to pre-stabilization slag standards ”applies to fly ash from municipal waste incineration

Extract analysis

monitored size leachate 1.extract 2.extract 3.extract total amount of extr. from gross waste (mg / kg) (i) Class II (mc / kc) ceik. amount of exur. from dry cdpad (mg / kg) standards V.?.pro dry cdp. (mg / kg) odor without match without match without match • color colorless colorless yellowish - - - - pH 7.45 7.4 7.3 - - - - more. occcr 783 2990 5460 • . - «, - (Ohm. Ca) DCO 54 7 41 1020 <5000 ^(i! 1495 (mg 0 ₂ / l) COT (ag / i) 6 4 3 130 <1 o ^ Vcoaí ' ) 190 <1500 volume (1) 1,000 1,000 1,000 - - - -

<l) _in mg / kg dry waste ^ in mg / kg gross waste

- 52 TabffRr # -continued -----

c a i: í i t í i í s fmcr / ll v total quantity n o r a y total. anoŽ3t. nonv. Elements 1.extract 2.extract 3.extract (mg / kg) extract from coarse. waste three cř.li extr.ze such. waste (mg / kg) V.?, Pru such.odp. (mg / kc) lead <0.310 <0.010 <0.010 <0.30 <100 <30 and i E <15 cadmium <0.010 <3.010 <0.010 <0.30 <50 <5 <0.44 <1 zinc <0.350 <0.050 <0.050 <1.50 <500 - <2.20 - copper <0.050 <0.050 <0.050 <1.50 - <20 <2.20 - nickel 0.370 <0.050 <0.050 0.70-1.70 <100 - 1.02-2.49 chrome <0.010 <0.010 <0.010 <0.30 <100 - <0.30 <1 Quicksilver <0.001 <0.001 <0.001 <0.03 <10 <0.2 <0.04 <0.2 cyanides NM NM NM - <10 - - - arsenic <0.010 <0.010. <0.010 <0.30 <10 <2 <0.44 <2 chlorides 155 25 7 1970 - <10000 2533 - sulphates 125 51 30 2070 - - 3033 <7000

NH: unmeasurable

Dissolution behavior

Prvicy r o z o u s t n o s t a disparate amount of gross. waste in conditions test (mg / kg) amount possibly soluble (total dry waste concentration) (mg / kg) zero decreasing permanent growing nickel X 0.70-1.70 1463 chlorides X 1970 20500 sulphates X 2070 13200

- 53 —Tabuika ^ ZJrTestToaaTiscvanáho-luženírpo-treatment with effluent Slag for Saiais II (S II)

physical character. waste results Class I standards * Class II standards ** standards of use for ver. plowman (V.2.) soluble fraction (dry waste) 0.34. <104 <54 <24 annealing losses (dry at 550 ° C) - <54 - <54 COT (dry) - - - - Bye 7.5 4 <p2 <13 - - dryness 95 4 > 354 - -

* refers to .standards for slags before stabilization ^tr applies to fly ash generated by incineration of municipal waste

Analysis of extracts

monitored size leachate 1.extract 2.extract 3.extract total amount of extr. from gross waste (mg / kg) (i) trraa? * 'class II ( ² (mg / kg) total. amount of dry waste extr. (mg / kg) standards IN.? / for dry cdp. (mg / kg) odor without match without match without match O barza colorless colorless colorless - - - Bye 7.5 7.4 7.3 - - - Mar. resistance (Ohm.cm) 1277 36Ó3 5555 - - - DCO (mg O ₂ / l) 43 3 3 540 <50COÍ ¹ ) 673 · » COT (mg / 1) 5 3 1 110 <IQ ^ ² V <400 ^ ² > 115 <1500 volume (1) 1,300 th most common 1,300 th most common 1,300 th most common - - - £ J

mg / kg dry waste and gross waste

- 54 .. _. Jábulka. 23i _ -continued ____

Elements Concentration (aa / L) v ceik.anozst7i (ag / kg) extrah. of gross. waste n o : a v total. anožst. sxtr.ze such. waste (ag / kg) standards 7.?.'pra such.odp. (ag / kg) i.exrraktu 2.extract 3. extract three class II lead <3.010 <0.010 <0.010 <0.20 <100 <20 <0.31 <15 cadmium <0.010 <0.010 <0.010 <0.30 <50 <5 <0.31 <i . zinc <0.350 <0.050 <0.050 <1.50 <500 - <1.53 - copper <0.0: 0 <0.050 <0.050 <1.50 - <20 <1.53 - nickel 0.120 <0.070 <0.050 2.30 <100 - 2.42 - chrome <0.010 <0.010 <0.010 <0.30 <100 - <0.31 <1 Quicksilver <0.001 <0.001 <0.001 <0.03 <10 <0.2 <0.03 <0.2 cyanides NM NM NH - <10 - - - arsenic <0.310 <0.010 <0.010 <0.30 <10 <2 <0.31 <2 chlorides * i w * 9 4 540 - <10000 673 - sulphates 240 63 38 3460 - - 3642 <7000

NM: not verifiable

Dissolution behavior

Elements rczoustnost soluble solubles rough. waste in the lodges. test (ag / kg) anniversaries or soluble (total dry waste concentration) (ag / kg) nuicvá decreasing permanent growing nickel AND 2.30 1463 chlorides X 640 20500 sulphates X 3460 18200

—----- Subsequently --------......_ i______According to an additional provision preferred by the invention - a previous biosorption of the metal elements from the extracts is carried out. These metals occur in a form very accessible to a number of biosorbents. In other words, the process of the invention can be advantageously supplemented by an added step of biosorption of metals precipitated from the treated slags as described above.

It is worth remembering that biosorption means the sequestration of metal ions by a natural solid. This general term includes very different mechanisms: particle uptake, active ion transport, complex formation, adsorption, and inorganic precipitation on the biosorbent.

The biosorbent, the use of which seems to be particularly advantageous, is chitosan.

Chitosan is derived from chitin (1y-M-acetyl-1-D-glucosamine). It is a carbohydrate polymer composed of a long linear polymer chain and glucosamine units attached to it by a G (1-4) g1 cosidic bond.

Chitosan is rare in nature; it is obtained by deacetylation of chitin, extracted from the outer shells of crustaceans, myriapods and other arthropods, from microorganisms and fungi.

The differences in the sources of chitin also result in great differences in the possible qualities of chitosan.

The deacetylation ratio, ranging from 80 to 100%, and the average molecular weight from 5,000 to 1,000,000 allow the formation of turbidity and reduce the viscosity and solubility of chitosan solutions. Its solubility and low degree of N-acetylation can only be achieved in a dilute acidic environment in the pH range <6. It depends on the presence of amino groups in the position of the C-2 glucosidic units, which give the polymer the properties of a weak polymer base.

Some authors state that the use of chitosan for water treatment is a question of the future. In Europe, however, PRO FLOC ^rM (Protan) is probably being developed for similar purposes. Its characteristics - is as follows - flakes or powder, form with a free amino group (-NH2), medium purity. In Japan, chitosan (chitosan pearls, Fujibo Inc., Shizuoka) is used to treat municipal and industrial waters. Another useful form of chitosan (used in the preliminary determinations to be described below) is SIGMA chitosan ”(ref. C.0792). However, other biosorbents can be used instead of chitosan, for example one of the substances described below can be selected. Their biosorption characteristics are not always identical to chitosan. The choice of biosorbent is often governed by the content of the extracts obtained by treating the slag according to the first part of the invention.

Various biosorbents capable of binding metals were used in preliminary determinations: chitin SIGMA ”(ref. C.3387), chitosan SIGMA” (ref. C.0792), biomass from chitosan fungus walls (Rhizopus arThizus), bacterial biomass (Zoogloea ramigera} and feather meal.

Method

In a 250 ml flask, mix 100 ml of a salt solution [cobalt: Co (NO3) 2, chromium: Cr (NO3) 2] at pH 4,0. 9H2O, copper: CuSO *. 5H2O, zinc: ZnSO4. 5H2O, cadmium: 3 CdSO <. 8H2O, or lead: Pb (NO3) 2j at a concentration of 100 g / l together with 100 mg of biosorbent (1 g / l), at the original state or crushed.

Incubate at 25 ° C with gentle agitation; samples were then taken. after 3 _, _ 6, 12, 24, 48 and 72 hours .__________

Analysis of elements in solution fix e emission spectrophotometry in plasma. On pictures 4 to 9 are shown relative curves adsorption kinetics lead, copper, chromium, cobalt, zinc a

cadmium to the biosorbents used.

Saline solutions used:

- lead nitrate (Fig. 4)

- copper sulphate (fig.5)

- chromate nitrate (Fig. 6)

- cobalt nitrate (Fig.7)

- zinc sulphate (Fig. 3)

- cadmium sulphate (Fig. 9)

The figures show the different absorption of metals (expressed in% of the initial content on the y-axis) depending on the time (given in hours Η) plotted on the x-coordinate axis.

Results

Under conditions unsuitable for biosorption (initial pH 4.0, the following findings were obtained on the adsorption of metals used in a salt / biosorbent weight ratio of 0.1:

lead is rapidly bound by Zoogloea ramigera up to 75 2 in 5 hours: by chitin and feather meal up to 30%, then the fixation is kinetically stopped. R. arrhizus binds the same metal evenly up to 30%, which is achieved after 72 hours.

Chitosan (according to Figure 4) does not capture lead under the same conditions.

Adsorption of copper is a very common product of chitin, fungal and bacterial feathers, or feather meal; its immobilization is close to 10% and remains almost constant.

The best copper adsorbent is chitosan, which stains in its presence. 50? copper sulfate is chelated within 72 hours (Fig. 5).

chromium shows affinity only for chitosan and reaches 6% adsorption during 72 hours of incubation (Fig. 6).

cobalt shows alternating adsorption and desorption with respect to all monitored biosorbents; the percentage varies between 2 and 8? (Fig. 6).

zinc shows a good affinity for Rhizopus arrhizus and chitosan (10% adsorption during 72 hours of incubation). The other polymers are not capable of chelating zinc under the specified conditions and given concentrations (Fig. 8).

cadmium is bound via chitosan up to 20? during 72 hours of incubation. Other biosorbents do not capture this metal (Fig. 9).

A comparison of these curves shows that, based on the choice of biosorbents used in the preliminary tests, it is possible to proceed to the treatment of leachates obtained by treating slags with a solution containing chloride ions, regardless of how much of these slags contain contaminating metals.

Some of the biosorbents used, less active under the specified conditions, may be more active under other conditions. An example is the capture of lead and copper by chitosan.

Some of the biosorbents are of particular importance because

--------- m ah. <w .__ be re ge ner o vány. In this oh. l.e du._ j.e — n e-j vý-z n-amis-ij-Si chitosan. Tests, briefly mentioned below, show its ability to regenerate using an ion exchanger or acid.

Another possibility is to increase the amount of biosorbent in relation to the element to be determined. Lead and zinc can serve as examples. Under the following conditions, the amount of lead trapped can increase significantly after a relative increase in the ratio of biosorbent to metal concentration.

Method

In 250 ml flasks, or 800 mg of chitosan with 100 ml of metals [CuSO4. 5H 2 O, ZnSO 4. 5H2O, or NSO4. 6H 2 O] o (acid treated, mixed with 100, 200, 400 saline solutions tested

CdSO4. 8H2O, Pb (NO3) 2 their own pH or pH 4.0 which corresponds to the conjugate base). After 24 hours of incubation at 25 ° C with gentle agitation, the mixture is centrifuged and 20 ml of supernatant is collected for plasma emission spectrophotometric determination. The 800 mg pellet is stored to measure desorption.

20 ml of distilled water are added to the pellet and the mixture is stirred for 1 hour. After centrifugation, the supernatant is used for analysis and the pellet is added to 0.1 M ammonium sulfate solution or to 1 N hydrochloric acid. After further mixing (shaking), the resulting supernatant is used again for analysis.

Results

Copper is the element that shows the best affinity for chitosan; at a salt / biosorbent ratio of 0.8, almost complete chelation of the metal occurs after 24 hours of contact. Initial pH apparently affect binding capacity biosorbents, but its alkalinity oriented environment pH to values approaching - ^ ^ acUnX - -kde- sezoenš u4e-co - ( »pet ic e ot _.pr ones _Λ

Desorption with ammonium sulphate is weak, which confirms the difficult exchange of bound metal. Changing the pH by the addition of hydrochloric acid aids in the ionization of the intermediate groups and leads to the salification of the chelated metal. Regardless of the losses during the experiment, the percentage of yield reaches 80%. In addition, the hydrochloric acid used to change the equilibrium state of the reaction may appear to change the structure of the chitosan; slight disintegration of the product was demonstrated. . According to the literature, sulfuric acid can be used to change the chemical equilibrium of the reaction without subsequent solubilization of chitosan.

Zinc, another of the metals tested, has a lower affinity than copper and is captured up to 60% in 24 hours at a salt / biosorbent ratio of 0.8. The pH of the medium changes in the same way as in the copper experiments.

Desorption in water appears to be washing rather than active desorption. Zinc is easily exchangeable, but its release becomes effective only after the addition of acid.

Of the monitored elements, cadmium behaves similarly to zinc. Within 24 hours, it achieves 60% fixation at the same ratio of salt and biosorbent.

In the presence of an ion exchange reagent, cadmium is strongly desorbed; complete desorption is induced by the addition of hydrochloric acid. However, the use of this acid as the sole desorbent is not sufficient to extract all the bound metal.

Lead is adsorbed up to 91% at a salt to biosorbent ratio of 0.8. This metal is difficult to replace and can be partially released by the addition of hydrochloric acid.

Mikl has a lower affinity for chitosan, with a salt to biosorbent ratio of 0.8 reaching 60% fixation within 24 hours. After shifting the reaction equilibrium by the addition of hydrochloric acid, it is effectively desorbed to 78% of the bound amount.

These results are the basis for considerations on the industrial use of the process of biosolting of polluting metals contained in the extracts, which arose during the treatment of the original slag, leading to its "inertization".

The diagram in Figure 10 shows the principle of the considered industrial arrangement. The leachates will be directed to a chitosan reactor or to a mixed plant, in the reactor of which another biosorbent (stabilized biomass) will be placed either separately or in a mixture. Reactor loop to completely purify water.

it will be possible to discharge the impurities into the river to wash the slag.

will be equipped with recycled water free of metal or reused

Like resin ion exchangers, chitosan can be regenerated by releasing metals by adding an acidic eluent and optionally transferring the biosorbent to other conditions by adding soda. Regeneration will be performed alternately by one of the treatment cycles (lanes I and II). The acidic eluent will be directed to the retention tank before final conversion to solid, but the yield will be evaluated later.

Very similar results for other biosorbents, such as metals and water recycling, will be achieved with fungal biotaiase using (which is particularly effective in treating calcium extracts).

Treatment of extracts using biomass from mushroom walls

Method

The lip coating was performed by constant stirring for 2 hours at 25 ° C without monitoring the pH. 100 ml of effluent (waste water) with a composition similar to slag extracts is added to 50, 100 or 250 mg of laboratory cultured fungal biomass (from Rhizopus arrhizus). The mineral element content is determined in solutions filtered through a Millipore membrane filter with a pore diameter of 3 and then 0.45 [mu] m.

Results

The results shown in Table 24 and shown in Figure 11 confirm that Rhizopus arrhizus is particularly effective at removing trace amounts of heavy metals from the calcium environment.

Treatment of leachates (Figure 12) with biomass (sedimentation)

In practice, waste water or leachates can be continuously treated by means of a device which forms a stirred bath fed with treated effluents and a decanter tank) for the separation of solid and liquid phases.

Liquid supernatants are removed and solids (biomass) are either recycled so that they are fed to full metal saturation or are desilted to their saturation. Finally, they are concentrated (final waste) and optionally destroyed, for example by incineration, or consolidated (eg by vitrification) for further storage.

Table 24 shows the results obtained. Figure 11 shows the results of assays using three different concentrations of Rhizopus arrhizus (test for adsorption of metals contained in effluents. Calculation of percent elimination and 52 confidence limits after 2 hours of incubation with Rhizopus arrhizus with agitation).

----------- Table 24: __ Heavy metal biosorption. Te-s-t — composition — of effluents before and after treatment with fungal biomass. The results are obtained from three determinations with a confidence limit of up to 5% and the concentration is given in qg / l.

Rhizopus Rhizopus (100 mg) Rhi zopus (250 mg) (50 mg) monitored k o n c and r i t r a c e • size ina initial final final final Pb (Ug / l) 15 5 ± 15 3 ± 2 2 ± 1 Cd (ug / l) 40 32 ± 0 20 and 1 14 + 13 Zn (ug / l) 615 210 ± 0 100 ± 0 50 + 0 Cu (pg / l) 40 10 ± 0 20 + 0 20 + 0 Ni (ug / l) Cr (Ug / l) 115 15 30 ± 0 30 ± 0 20 + 0 Ca (g / 1) 2.70 2.78 2.73 2.71 COT (mg / 1) 7, Sil, 4 13.7 ± 1.9 19.7 ± 3.9 32.8 ± 3.8

Detection threshold for determined mineral elements in ug / l '· Pb <25, Cd <10, Zn <50, Cu <50, NiClOO, Cr <10

These results confirm the effectiveness of the set of methods according to the invention. The principle of one of the preferred methods is shown in Figure 13.

It follows from the foregoing that the process according to the invention leads to the recovery of combustion residues which, after treatment, comply with the European definition of inert waste and correspond to the values required for the use of substances in public works.

Furthermore, the mobile fraction of heavy metals, originally contained in the waste, was concentrated to a much smaller mass than the mass of the original slag.

Finally, the treatment method described here will not lead to the transfer of pollution to the natural environment.

I '4

X 'Ό ín

Claims (9)

A method of stabilizing combustion residues, in particular slags of any origin, by extracting soluble metal fractions, comprising performing one or more leaching slags, if necessary pre-crushed to a low particle size, to values of less than 50 mm so as to ensure sufficient contact between the residues after combustion and an aqueous solution or leaching agent, characterized in that the aqueous solution or leaching agent comprises - either with dilute hydrochloric acid, if the combustion residues are basic, - or with an alkali metal or alkaline earth chloride solution (cations K ⁺ , Na ⁺ , Ca ²⁺ ) if the combustion residues are neutral, the protons of the dilute hydrochloric acid solution or the cations of the alkali metals or alkaline earths of the chloride solutions are in sufficient concentrations with respect to exchangeable the heavy metal cations present in the combustion residues, the leaching being carried out in a number to ensure that the exchangeable heavy metals contained in the combustion residues are converted into soluble chlorides extractable by the leaching agent, and the subsequent combustion of the combustion residues by three repeated extractions with a standard elution solution, consisting of demineralized water, saturated air and CO ₂ at pH 4.5, whose resistivity is 0.2 to 0.4 M.cm, as well as their effective extraction, where the quantities of the following elements are still extracted in the total volume of extraction solutions. The collections resulting from three additional extractions with a standard solution below the following thresholds: -------- non-combustible - residues - <_5% ____________________________________________________________________________ soluble fraction <3% Hg <0.2 mg / kg dry matter Pb <4 mg / kg dry matter Cd <1 mg / kg dry matter Cu <20 mg / kg dry matter As <2 mg / kg dry matter Cr ^v - £ <1 mg / kg dry matter sulphates <4000 mg / kg dry matter chlorides <2800 mg / kg dry matter COT <1000 mg / kg dry matter Method according to claim 1, for treating basic slags, characterized in that the concentration of hydrochloric acid in the solution or slag leaching agent is a molar concentration ranging from 0.01 M to 1.0 M, preferably equal to 0.1 M. The method of claim 1 for treating neutral slags, wherein the leaching solution or agent is an alkali metal or alkaline earth chloride solution. Method according to claim 3, characterized in that the concentration of the alkali metal or alkaline earth chloride in the solution or leaching agent is in the range from 0.01 M and in particular from 0.05 M to 5.0 M. The method of claim 4, wherein the leaching solution or agent is a potassium chloride solution. Method according to claim 5, characterized in that the concentration of potassium chloride is in the order of 1 M. The method according to claim 5, characterized in that the chloride is calcium chloride, whose concentration lies in the range of 0.01 M to 5 M, in particular 0.05 to 5.0 M and is in particular equal to 0.09 M to 0.15 M. Method according to claim 7, characterized in that the concentration of calcium chloride is in the order of 0.09 M. The method of any one of claims 1 to 8, wherein the leach solutions or reagent collected from the treated combustion residues are biosorbed using biosorbents capable of sequestering at least a significant portion of the metal heavy metal ions extracted of these combustion residues " 10. The method of claim 9 wherein the biosorbent is chitosan based. Method according to claim 9, characterized in that the biosorbent is composed of a biomass, in particular a fungal or bacterial, product of biological cultures or fermentation.