Process for treating polluted soils by means of a sulfoaluminate clinker based hydraulic binder and use thereof for stabilizing polluted soils

Abstract

A process for treating polluted soils, in particular soils with a leachable fraction greater than 0.4%, wherein the leachable fraction contains predominantly anions, in particular sulfate ions, and/or heavy metals, includes mixing the soil with a sulfoaluminate-clinker-based hydraulic binder, in soil/binder weight proportions of between 1 and 40 parts of binder per 100 parts of soil, the sulfoaluminate clinker containing more than 50% by weight of ye'elimite C.sub.4A.sub.3S phase, less than 15% by weight of belite C2S phase, and from 1% to 5% by weight of free lime CaO. The process is used for stabilizing soils in situ or before dumping, soils polluted in particular with sulfate anions and/or heavy metal cations.

Claims

1. A process for the treatment of polluted soils, in particular of soils exhibiting a leachable fraction of greater than 0.4%, said leachable fraction predominantly including anions sulfate ions, and/or heavy metals, wherein said process comprises the mixing of said soil with a hydraulic binder based on sulfoaluminate clinker in soil/binder proportions by weight of between 1 and 40 parts of binder per 100 parts of soil, said sulfoaluminate clinker including more than 50% by weight of ye'elimite C4A3$ phase, less than 15% by weight of belite C2S phase and from 1% to 5% by weight of free lime CaO, and wherein said sulfoaluminate clinker includes from 2% to 12% by weight of mayenite C.sub.12A.sub.7 phase or of a mayenite isotype.

2. The treatment process as claimed in claim 1, wherein the sulfoaluminate clinker includes more than 60% by weight of ye'elimite C4A3 $ phase.

3. The treatment process as claimed in claim 1, wherein the sulfoaluminate clinker includes from 5% to less than 15% by weight of belite C2S phase.

4. The treatment process as claimed in claim 1, wherein said process comprises the mixing of said soil with the hydraulic binder in soil/binder proportions by weight of between 1 and 20 parts of binder per 100 parts of soil.

5. The treatment process as claimed in claim 4, wherein said process comprises the mixing of said soil with the hydraulic binder in soil/binder proportions by weight of between 5 and 20 parts of binder per 100 parts of soil.

6. The treatment process as claimed in claim 1, wherein the hydraulic binder is composed solely of a sulfoaluminate clinker including more than 50% by weight of ye'elimite C4A3 $ phase, less than 15% by weight of belite C2S phase and from 1% to 5% by weight of free lime CaO.

7. The process as claimed in claim 1, wherein said hydraulic binder does not include a setting accelerator.

8. The process as claimed in claim 1, wherein said hydraulic binder includes at least 20% by weight of said sulfoaluminate clinker and one or more compounds chosen from cement, Portland clinker, lime, a filler, admixtures having a pozzolanic effect, and optionally one or more additives.

9. The process as claimed in claim 8, wherein said hydraulic binder includes quick lime in an amount of less than 50% by weight.

10. A process for the stabilization of soils, which soils are polluted in particular by sulfate anions and/or heavy metal cations, said process comprising the steps of: mixing said soils with a hydraulic binder based on sulfoaluminate clinker in soil/binder proportions by weight of between 1 and 40 parts of binder per 100 parts of soil, said sulfoaluminate clinker including more than 50% by weight of ye'eliminate C4A3$ phase, less than 15% by weight of belite C2S phase and from 1% to 5% by weight of free lime CaO and from 2% to 12% by weight of mayenite C.sub.12A.sub.7 phase or of a mayenite isotype, wherein said mixing is either one of in situ in the soil to be treated or said mixing is performed with said soil prior to landfilling.

11. The process as claimed in claim 10 wherein the soil prior to treatment has a water content of less than 40% by weight.

12. The process as claimed in claim 10, wherein said method further includes the step of depositing said soil, treated by said process in road bases or backfills.

13. The treatment process as claimed in claim 3, wherein the sulfoaluminate clinker includes from from 8% to 13% by weight of belite C2S phase.

14. The treatment process as claimed in claim 1, wherein the sulfoaluminate clinker includes from 2% to 3% by weight of mayenite C.sub.12A.sub.7 phase or of a mayenite isotype.

15. The treatment process as claimed in claim 4, wherein said process comprises the mixing of said soil with the hydraulic binder in soil/binder proportions by weight of between 2 and 20 parts of binder per 100 parts of soil.

16. The treatment process as claimed in claim 5, wherein said process comprises the mixing of said soil with the hydraulic binder in soil/binder proportions by weight of between 5 and 10 parts of binder per 100 parts of soil.

17. The process as claimed in claim 8, wherein said hydraulic binder includes at least 30% by weight of said sulfoaluminate clinker and one or more compounds chosen from cement, Portland clinker, lime, a filler, admixtures having a pozzolanic effect, and optionally one or more additives.

18. The process as claimed in claim 11 wherein the soil prior to treatment has a water content of less than 30% by weight.

Description

EXAMPLES

1Preparation of the Clinkers

(1) The clinkers according to the present invention are prepared by burning, at a temperature of between 1000 C. and 1200 C., a raw mix composed of limestone, clay and bauxite which are mixtures of different oxides, in particular CaO, SiO.sub.2, Al.sub.2O.sub.3, Fe.sub.3O.sub.2 and SO.sub.3, according to the as yet unpublished patent application PCT/EP2011/070116.

(2) It is important to note that, in the context of the present invention, the starting materials constituting the raw mix (mixture of the minerals before burning) are proportioned in order to obtain a sulfoaluminate binder and not a high-alumina binder.

(3) After burning, the clinker is cooled in ambient air and then ground in order to obtain a Blaine fineness of the order of 4000 cm.sup.2/g and a particle size of less than approximately 40 micrometers. The mineralogical compositions of two sulfoaluminate clinkers according to the invention are presented in table 1.

(4) TABLE-US-00001 TABLE 1 Clinker A Clinker C C.sub.4A.sub.3$ 63.3 61.4 C.sub.2S 11 11.2 C$ 3.1 8.7 C.sub.9S.sub.3$.sub.3CaF.sub.2 11.4 <0.5 C.sub.12A.sub.7 2.6 <0.5 C.sub.3s <0.5 4.1 C.sub.2AS <0.5 2.9 C.sub.4AF 2.3 4.1 CT 1 3.3 K.sub.2SO.sub.4 <0.5 2.1 MgO 5.2 <0.5 C.sub.3A <0.5 1.7 C <0.5 <0.5 CH <0.5 0.6

(5) (In this table 1, CaF.sub.2 represents fluorine)

2Treatment Process

(6) The process for the treatment of a contaminated material (such as a polluted soil) with a hydraulic binder based on sulfoaluminate clinker according to the invention was carried out according to the following stages:

(7) an amount of crude earth is sieved at 4 mm (Saulas, France, Sieve, certified NF ISO 3310), so as to obtain 1 kg of earth to be treated (contaminated material).

(8) 1 kg of sieved earth to be treated (contaminated material) is placed in a mixer (MLX40D, CAD France) in the presence of a predetermined amount of sulfoaluminate hydraulic binder, expressed as % by weight of binder with respect to the weight of contaminated material.

(9) The earth/binder mixture is then subjected to a stage of homogenization by slow-speed mixing (140 revolutions/minute) for 1 minute. The water is then added according to a Water/Binder ratio by weight equal to 1.

(10) The combined mixture is then mixed at slow speed for 2 minutes and then at high speed (285 revolutions/minute) for 2 minutes. The entire contents of the mixer are then poured into a plastic bag (polyethylene bag, 3 liters), which is then hermetically closed so as to simulate storage in a pile. The treated earth is matured over a period of time of 1 week at ambient temperature.

(11) The treated material is subsequently dried at 40 C. in an oven and then optionally crushed (BB 200 Tungsten Carbide, Retsch, Germany) to a particle size of less than 4 mm in order to carry out the leaching tests.

3Leaching Process

(12) In accordance with the abovementioned Directive which defines the classes of dangerousness, the standard NF EN-12457-2 was used for the leaching tests.

(13) The tests are carried out on a material, at least 95% of the particles (by weight) of which have a size less than the 4 mm sieve.

(14) A sample of 350 g of crude material is sieved with the 4 mm sieve. The oversize at 4 mm is subjected to crushing in order to obtain a zero oversize at this sieve, and the combined product is mixed in order to obtain the sample which will be subjected to the leaching test.

(15) For the analyses and the leaching tests, the weight of dry matter (w.sub.d) of the sample is determined after transfer to an oven at 105 C.5 C. to a constant weight in accordance with the standard ISO 11465.

(16) Leaching Test

(17) The starting sample w.sub.leach is 90 g0.5 g (measured with an accuracy of 0.1 g) of dry matter.

(18) The leaching test is carried out at ambient temperature, i.e. 20 C.5 C., in a one liter flask in the presence of an amount of leachant (deionized water, 18 M) equivalent to a liquid/solid (L/S) ratio by weight of 102%. The stoppered flask is placed in an overhead shaker (Heidolph REAX 20) at approximately 10 revolutions/min and shaken for 24 hours0.5 h. In addition to the samples, leaching blanks are also carried out.

(19) After halting the shaking, the suspended solids are left to settle out for 15 min5 min and then filtered under vacuum through a 0.45 m membrane filter.

(20) The eluate is subsequently divided into an appropriate number of subsamples for the different chemical analyses and is stored according to the standard EN ISO 5667-3.

(21) The analysis of the elements (heavy metals) is carried out by ICP-AES (inductively coupled plasma-atomic emission spectrometry) analysis (Iris Advantage, Thermo Jarrell Ash) according to a protocol in accordance with the standard NF EN ISO 11885.

(22) The analysis of the anions is carried out by ion chromatography (ICS 2000, Dionex, USA) according to a procedure in accordance with the standard NF EN ISO 10304-1.

(23) The soluble fraction (SF) is calculated according to the following equation:

(24) $SF=\frac{[\left(w_1-w_0\right)\left(0.9+\left(0.001w_{\mathrm{leach}}{c}_{\mathrm{moisture}}\right)\right]}{\left(0.001V_{\mathrm{ext}}{w}_{\mathrm{leach}}\left(1-c_{\mathrm{moisture}}\right)\right)}$
w.sub.1w.sub.0=w.sub.d=weight of the sample dried in the oven at 105 C. (in grams)
w.sub.leach=weight of the sample for leaching (in grams)
c.sub.moisture=moisture content of the sample (in grams)
V.sub.ext=volume withdrawn for measuring the solids content (in milliliters).

(25) In the continuation of the document, SF is expressed as %. In the abovementioned Directives, SF is expressed in mg/kg. The value of 1% is equivalent to 10 000 mg/kg.

(26) Reference Samples

(27) All the tests carried out here were carried out starting from earth from the Autonomous Port of Paris, earth excavated from a former industrial site where an incineration plant was active at Issy-les-Moulineaux near Paris.

(28) The earth from the Port of Paris constitutes a polluted soil, also known as contaminated material, within the meaning of the present invention, the substrate being the earth and the pollutants being the different elements or ions present in significant amounts in this earth.

(29) Sample 1

(30) Sample 1 is a crude sample of earth from the Autonomous Port of Paris. This sample 1 has not been subjected to leaching. Its water content is approximately 15% by weight.

(31) Samples 2 and 3

(32) Samples 2 and 3 correspond to the analysis of two leachates of earth from the Port of Paris.

(33) The assays of the different pollutants present in the crude sample 1 and with regard to the leachates (samples 2 and 3) are combined in table 2.

(34) The values of the elements and ions assayed are expressed in mg/kg of dry matter.

(35) The soluble fraction represents the total amount of chemical elements passing in the solution with respect to the amount of initial dry material, expressed as % of dry matter.

(36) TABLE-US-00002 TABLE 2 Sample 1 Sample 2 Sample 3 (crude earth) (leachate) (leachate) As 53 <0.2 <0.2 Ba 769 0.471 0.34 Cd 5 0.114 <0.1 Cu 798 0.253 <0.2 Hg <3 <0.1 <0.002 Ni 107 0.127 <0.100 Pb 1454 0.115 <0.350 Sb 47 <0.2 <0.500 Se <5 <0.2 <0.400 Zn 1163 0.375 <0.200 Cl.sup. 68.7 68.7 24 SO.sub.4.sup.2 9400 6859 7532 SF (Soluble 1.18 1.2 fraction)

(37) The results of this table 2 show that the main leachable elements and thus the main elements constituting pollutants are the anions, in particular the sulfates. The contents of leached sulfates have the consequence of bringing the earth into class II according to Directive 1999/31/EC of the Council of 26 Apr. 1999 for the landfilling thereof. The value of the soluble fraction (of between 0.4% and 6.0%) also brings about a classification in category II.

(38) Sample 2 is selected in the examples below as reference for measuring the effectiveness of the different binders.

Example 1

Sample 4

(39) Sample 4 corresponds to the treatment of a sample of earth from the Port of Paris with 10% (by weight) of a sulfoaluminate hydraulic binder according to the invention. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1.

Example 2 (Comparative)

Sample 5

(40) Sample 5 corresponds to the treatment of a sample of earth from the Port of Paris with 10% (by weight) of a binder sold by Holcim under the trade name Inercem. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1.

Example 3 (Comparative)

Sample 6

(41) Sample 6 corresponds to the treatment of a sample of earth from the Port of Paris with 20% by weight of a binder sold by Ciment Calcia under the trade name Ligex FPL1. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1.

(42) All of these results are combined in table 3.

(43) TABLE-US-00003 TABLE 3 Sample 2 Sample 4 Sample 5 Sample 6 (reference) (10% binder) (comparative) (comparative) As <0.2 <0.3 <0.3 <0.2 Ba 0.471 0.698 0.425 0.986 Cd 0.114 <0.1 <0.1 <0.1 Cu 0.253 0.263 <0.2 0.269 Hg <0.1 <0.1 <0.1 <0.1 Ni 0.127 <0.1 <0.1 <0.1 Pb 0.115 <0.35 <0.35 <0.1 Sb <0.2 <0.5 <0.5 <0.2 Se <0.2 <0.4 <0.4 <0.2 Zn 0.375 <0.2 <0.2 0.317 Cl.sup. 68.7 311 59 99 SO.sub.4.sup.2 6859 2305 8968 4322 SF % 1.18 0.6 1.32 0.96

(44) It is observed that the treatment with the Inercem binder does not make it possible to lower the amount of sulfate entrained in the leachate, unlike the treatment with a sulfoaluminate hydraulic binder according to the invention, which makes it possible, with a small amount of hydraulic binder (10% by weight), to reduce by more than 60% the content of sulfates in the leachate. The treatment with the Ligex FPL1 binder makes it possible to reduce the amount of sulfate but in a lower proportion than the treatment with a sulfoaluminate hydraulic binder according to the invention.

(45) It is also observed that the use of Inercem does not make it possible to reduce the soluble fraction of the earth, unlike the sulfoaluminate hydraulic binder according to the invention. The treatment with Ligex FLP1 makes it possible to reduce the soluble fraction but less effectively than the sulfoaluminate hydraulic binder.

Example 4: Treatment with Different Proportions of Binder

(46) Samples 7, 8, 9 and 10 correspond to the treatment of a sample of earth from the Port of Paris with respectively 5%, 15%, 20% and 40% (by weight) of a sulfoaluminate hydraulic binder according to the invention including 100% of clinker A. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results are presented in table 4.

(47) TABLE-US-00004 TABLE 4 Sample Sample Sample Sample Sample Sample 2 7 (5% 4 (10% 8 (15% 9 (20% 10 (40% (reference) binder) binder) binder) binder) binder) As <0.2 <0.3 <0.3 <0.3 <0.2 <0.3 Ba 0.471 0.467 0.698 0.811 1.2 0.623 Cd 0.114 <0.1 <0.1 <0.1 <0.1 <0.1 Cu 0.253 <0.2 0.263 0.508 0.367 0.431 Hg <0.1 <0.001 <0.1 <0.001 <0.002 <0.001 Ni 0.127 <0.1 <0.1 <0.1 <0.100 <0.1 Pb 0.115 <0.350 <0.35 <0.350 <0.350 <0.350 Sb <0.2 <0.5 <0.5 <0.5 <0.500 <0.5 Se <0.2 <0.4 <0.4 <0.4 <0.400 <0.4 Zn 0.375 <0.2 <0.2 <0.2 <0.200 <0.2 Cl.sup. 68.7 191 311 366 384 575 SO.sub.4.sup.2 6859 6200 2305 1606 1287 1158 SF 1.18 0.99 0.6 0.66 0.81 1.05

(48) It is observed that the stabilization of the sulfates of the earth is a function of the amount of sulfoaluminate hydraulic binder according to the invention used. The change in the concentrations of sulfates in the leachates of the earths treated shows the effectiveness of the stabilization increases significantly with the amount of sulfoaluminate hydraulic binder according to the invention used for the treatment, provided that the percentage by weight of binder used is greater than or equal to 10%. Beyond 10%, the stabilization of the sulfate also improves but at a lesser rate.

(49) These results are represented diagrammatically on the graph of the appended FIGURE. The graph represents the variation in sulfate ions, expressed as ppm (or mg/kg of material treated), in the leachate (represented on the axis of the ordinates) as a function of the percentage by weight of hydraulic binder according to the invention used to treat the contaminated soil (represented on the axis of the abscissa).

Example 5: Treatment with Hydraulic Binders of Different Compositions

(50) Sample 11

(51) Sample 11 corresponds to the treatment of a sample of earth from the Port of Paris with 20% (by weight) of hydraulic binder according to the invention, said hydraulic binder comprising 50% of sulfoaluminate clinker and 50% of CEM I cement (CEM I 52.5 N from Couvrot). The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1.

(52) Sample 12

(53) Sample 12 corresponds to the treatment of a sample of earth from the Port of Paris with 20% (by weight) of a hydraulic binder according to the invention, said hydraulic binder comprising 90% of sulfoaluminate clinker and 10% of CaO. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1.

(54) The results of these two tests are collated in table 5 and compared with sample 9 carried out with the same amount of sulfoaluminate hydraulic binder according to the invention comprising 100% of clinker A.

(55) TABLE-US-00005 TABLE 5 Sample 2 Sample 11 Sample 12 Sample 9 (reference) (20% binder) (20% binder) (20% binder) As <0.2 <0.2 <0.3 <0.2 Ba 0.471 0.545 0.615 1.2 Cd 0.114 <0.1 <0.1 <0.1 Cu 0.253 0.88 0.627 0.367 Hg <0.1 <0.001 <0.001 <0.002 Ni 0.127 <0.1 <0.1 <0.100 Pb 0.115 <0.350 <0.350 <0.350 Sb <0.2 <0.5 <0.5 <0.500 Se <0.2 <0.2 <0.4 <0.400 Zn 0.375 <0.2 <0.2 <0.200 Cl.sup. 68.7 107 246 384 SO.sub.4.sup.2 6859 810 969 1287 SF 1.18 0.63 0.77 0.81

(56) It is noted that the presence of CaO and/or of CEM I cement makes it possible to further lower the content of sulfates in the leachate.

Example 6: Treatment with Adjuvant-Treated Binders

Sample 13

(57) Sample 13 corresponds to the treatment of a sample of earth from the Port of Paris with 20% (by weight) of a sulfoaluminate hydraulic binder according to the invention including 99.7% of clinker A and 0.3% of lithium carbonate (Li.sub.2CO.sub.3). The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 6, in comparison with those of sample 9 treated with the same proportion of sulfoaluminate hydraulic binder according to the invention.

(58) TABLE-US-00006 TABLE 6 Sample 2 Sample 13 Sample 9 (reference) (20% binder) (20% binder) As <0.2 <0.2 <0.2 Ba 0.471 1.2 1.2 Cd 0.114 <0.1 <0.1 Cu 0.253 0.23 0.367 Hg <0.1 <0.1 <0.002 Ni 0.127 <0.1 <0.100 Pb 0.115 <0.1 <0.350 Sb <0.2 <0.2 <0.500 Se <0.2 <0.2 <0.400 Zn 0.375 <0.2 <0.200 Cl.sup. 68.7 401 384 SO.sub.4.sup.2 6859 810 1287 SF 1.18 0.65 0.81

(59) It may be noted that the use of additive, such as a setting accelerator based on lithium carbonate, makes it possible to further increase the capacity for stabilization of the sulfates of the sulfoaluminate binder, the content of sulfate passing below 1000 ppm in the leachate.

Example 7: Treatment with Binders Comprising Quick Lime

(60) Samples 14 and 17 correspond to the analysis of two leachates of earth from the Port of Paris. They are subjected to leaching under the same conditions as above (samples 2 and 3) and constitute two separate references in this example 7.

(61) Sample 15 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 14) with 6% (by weight) of a sulfoaluminate hydraulic binder according to the invention including 75% of clinker A and 25% of quick lime. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 7, in comparison with those of samples 14 and 16.

(62) Sample 16 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 14) with 4% (by weight) of a sulfoaluminate hydraulic binder according to the invention including 75% of clinker A and 25% of quick lime. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 7, in comparison with those of samples 14 and 15.

(63) TABLE-US-00007 TABLE 7 Sample 14 Sample 15 Sample 16 (reference) (6% binder) (4% binder) As <0.2 <0.2 <0.2 Ba 0.347 0.819 0.707 Cd <0.1 <0.04 <0.04 Cu 0.234 0.292 0.244 Hg 0.019 0.01 0.004 Ni <0.1 <0.05 <0.05 Pb <0.1 <0.1 <0.1 Sb 0.222 <0.06 <0.06 Se <0.2 <0.08 <0.08 Zn <0.2 <0.05 <0.05 Cl.sup. 139 146 161 SO.sub.4.sup.2 4517 1428 1750 SF 0.61 0.65 0.60

(64) Sample 18 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 17) with 6% (by weight) of a sulfoaluminate hydraulic binder according to the invention including 66.7% of clinker A and 33.3% of quick lime. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 8, in comparison with those of samples 17 and 19.

(65) Sample 19 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 17) with 4% (by weight) of a sulfoaluminate hydraulic binder according to the invention including 50% of clinker A and 50% of quick lime. The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 8, in comparison with those of samples 17 and 18.

(66) TABLE-US-00008 TABLE 8 Sample 17 Sample 18 Sample 19 (reference) (6% binder) (4% binder) As <0.2 <0.2 <0.2 Ba 0.438 0.821 0.733 Cd <0.1 <0.04 <0.04 Cu <0.2 0.557 0.677 Hg 0.004 0.004 0.006 Ni <0.1 <0.05 <0.05 Pb <0.1 <0.1 <0.1 Sb <0.2 <0.06 <0.06 Se <0.2 <0.08 <0.08 Zn <0.2 <0.05 <0.05 Cl.sup. 181 209 172 SO.sub.4.sup.2 4696 730 691 SF 0.91 0.59 0.39

Example 8: Treatment with Pure Mineralogical Phases

(67) Samples 20 to 24 correspond to treatments carried out with binders obtained from pure mineralogical phases, that is to say that the clinkers used do not originate from a cement furnace but from a laboratory. These samples are compared with the reference sample 17 described in example 7.

(68) Sample 20 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 17) with 5% (by weight) of a hydraulic binder according to the invention including 100% of ye'elimite (100% Y). The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 9.

(69) Sample 21 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 17) with 5% (by weight) of a hydraulic binder according to the invention including 60% of ye'elimite and 40% of quick lime (60% Y/40% CaO). The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of leachate are presented in table 9.

(70) Sample 22 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 17) with 5% (by weight) of a hydraulic binder according to the invention including 80% of ye'elimite (Y) and 20% of quick lime (80% Y/20% CaO). The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 9.

(71) TABLE-US-00009 TABLE 9 Sample 22 Sample 17 Sample 20 Sample 21 (80% (reference) (100% Y) (60% Y/40% CaO) Y/20% CaO) As <0.2 <0.2 <0.2 <0.2 Ba 0.438 0.443 0.552 0.637 Cd <0.1 <0.05 <0.05 <0.05 Cu <0.2 0.159 0.513 0.170 Hg 0.004 0.045 0.093 0.067 Ni <0.1 <0.05 <0.05 <0.05 Pb <0.1 <0.1 <0.1 <0.1 Sb <0.2 <0.1 <0.1 <0.1 Se <0.2 <0.1 <0.1 <0.1 Zn <0.2 <0.05 <0.05 <0.05 Cl.sup. 181 172 156 161 SO.sub.4.sup.2 4696 2200 633 532 SF 0.91 0.66 0.71 0.96

(72) Sample 23 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 17) with 5% (by weight) of a hydraulic binder according to the invention including 70% of ye'elimite, 20% of mayenite and 10% of quick lime (70% Y/20% M/10% CaO). The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 10.

(73) Sample 24 corresponds to the treatment of a sample of earth from the Port of Paris (same source as reference sample 17) with 5% (by weight) of a hydraulic binder according to the invention including 50% of ye'elimite, 20% of mayenite and 30% of quick lime (50% Y/20% M/30% CaO). The amount of water used in producing this sample corresponds to a Water/Binder ratio equal to 1. The results of the analysis of the leachate are presented in table 10.

(74) TABLE-US-00010 TABLE 10 Sample 23 Sample 24 Sample 17 (70% Y/20% (50% Y/20% (reference) M/10% CaO) M/30% CaO) As <0.2 <0.2 <0.2 Ba 0.438 0.763 0.552 Cd <0.1 <0.05 <0.04 Cu <0.2 0.142 0.296 Hg 0.004 0.007 0.022 Ni <0.1 <0.05 <0.05 Pb <0.1 <0.1 <0.1 Sb <0.2 <0.1 <0.06 Se <0.2 <0.1 <0.08 Zn <0.2 <0.05 <0.05 Cl.sup. 181 143 142 SO.sub.4.sup.2 4696 389 592 SF 0.91 1.05 0.9