Coated pipeline or tank element

Abstract

The present invention relates to a coated pipeline or tank element (10) comprising a raw pipeline or tank element (12) made of ductile iron, steel or concrete, and an inner liner (18) located on an inner wall (14) of the raw pipeline or tank element (12), the inner liner (18) being formed from a mortar composition comprising a cement and a magnesium-based additive. It also relates to a pipeline or tank comprising one or more of these coated pipeline or tank elements, the pipeline or tank preferably being intended for the supply, distribution or storage of potable water.

Description

Title of the invention: Coated pipe or tank element

[0001] The present invention relates to a pipeline or reservoir element comprising a particular mineral interior coating, said element being advantageously adapted to the supply, distribution or storage of drinking water. It also relates to a pipeline or reservoir comprising such an element.

[0002] Pipe or tank elements made of ductile iron, steel or concrete have been used for many years for the supply, distribution or storage of drinking water. The inner wall of these elements is generally covered with a mortar in order to provide protection by a passivation mechanism. During commissioning, the water gradually soaks the mortar, and is enriched with alkaline elements and thus becomes non-corrosive when it reaches the wall of the pipe or tank element.

[0003] However, it has been found that certain metals present in the composition of the mortar, such as chromium, vanadium, antimony, or aluminum, were released into the water in contact with the latter. Regulations impose increasingly strict constraints regarding the metal contents in water, particularly drinking water.

[0004] Thus, there remains a real need to have a pipe or tank element coated with a mortar releasing less metal into the water. Summary of the invention

[0005] In this context, the inventors have demonstrated that the addition of a magnesium-based additive to the cement mortar composition used to coat the inner wall of the pipe or tank element makes it possible to substantially reduce the levels of certain metals released into the water. The inventors were able to observe that these performances could be achieved even with low levels of magnesium-based additive.

[0006] Advantageously, it has been shown that the coating retains good mechanical properties.

[0007] Thus, the present invention relates to a coated pipe or tank element comprising:

[0008] - a raw pipe or tank element made of ductile iron, steel or concrete, and

[0009] - an inner coating located on an inner wall of the pipe element or of raw tank, the interior coating being formed from a mortar composition comprising:

[0010] - a cement and

[0011] - a magnesium-based additive.

[0012] The invention also relates to a pipeline or reservoir comprising one or more coated pipeline or reservoir elements as described in the present application, the pipeline or reservoir preferably being intended for the supply, distribution or storage of drinking water. FIGURES

[0013] [Fig.l]: Schematic cross-sectional representation of a coated pipeline or tank element, in a particular embodiment of the invention. DETAILED DESCRIPTION

[0014] The coated pipeline or tank element according to the invention comprises:

[0015] - a raw pipeline or tank element made of ductile iron, steel or concrete, and

[0016] - an inner coating located on an inner wall of the pipe element or of raw tank.

[0017] The coated pipe or tank element defines an interior space in which the liquid (typically water) can circulate in contact with the interior coating.

[0018] The raw pipe or tank element may for example be a pipe or a branch, or form a tank.

[0019] In some embodiments, the coated pipeline or tank element further comprises an outer coating located on an outer wall of the raw pipeline or tank element. The outer coating is advantageously suitable for contact with a ground. The outer coating, well known to those skilled in the art, is advantageously configured to increase the corrosion resistance of the raw pipeline or tank element. This outer coating is generally formed of a metallic protective layer, in particular based on sacrificial zinc, covered with a pore-filling paint based on an organic resin.

[0020] The interior coating advantageously covers the entire interior wall of the raw pipe or tank element.

[0021] The inner coating advantageously has a nominal thickness of 2 to 15 mm, preferably 2.5 to 9 mm.

[0022] The interior coating is a mortar formed from a mortar composition comprising:

[0023] - a cement and

[0024] - a magnesium-based additive.

[0025] More particularly, the inner coating is a mortar, typically formed by applying said mortar composition to the inner wall of the raw pipe or tank element and then allowing said composition to harden (or set). mortar. The application of the mortar composition can be done by centrifugation, projection or manual coating.

[0026] A cement is a hydraulic mineral compound, that is to say which sets on contact with water by hydration.

[0027] The cement generally comprises clinker, and preferably one or more constituents selected from blast furnace slag, steel slag, fly ash, pozzolan, silica fume, limestone, and calcined clay.

[0028] The cement may for example be a Portland cement, a composite Portland cement, a blast furnace slag cement, a composite cement, a pozzolanic slag cement, a calcined limestone and clay cement, an aluminous cement, a sulfo-aluminous cement, a supersulfated cement, a quick-setting cement or a mixture thereof.

[0029] The cement is advantageously a cement as defined by standard EN 197-1 or standard EN 197-5. Unless otherwise indicated, the weight contents indicated for the constituents of a cement defined by standard EN 197-1 or standard EN 197-5 are as defined by standard EN 197-1 or standard EN 197-5 respectively.

[0030] In some embodiments, the cement is a Portland cement CEM I of the EN 197-1 standard. The clinker content of a Portland cement CEM I of the EN 197-1 standard is at least 95% by weight.

[0031] In some embodiments, the cement is a CEM II compound Portland cement of EN 197-1. A CEM II compound Portland cement of EN 197-1 results from mixing clinker in an amount at least equal to 65% by weight and other constituents such as blast furnace slag, fly ash, pozzolans, silica fume, the total of which does not exceed 35% by weight.

[0032] In some embodiments, the cement is a CEM II / AS or CEM II / BS Portland slag cement of EN 197-1. The CEM II / AS cement comprises 80 to 94% by weight of clinker and 6 to 20% by weight of blast furnace slag. The CEM II / BS cement comprises 65 to 79% by weight of clinker and 21 to 35% by weight of blast furnace slag.

[0033] In some embodiments, the cement is a CEM II / CM composite Portland cement of EN 197-5, including a CEM II / CM (SP), CEM II / CM (SV), CEM II / CM (SL), CEM II / CM (S-LL), CEM II / CM (PL), CEM II / CM (VL), CEM II / CM (P-LL), or CEM II / CM (V-LL) cement of EN 197-5. The CEM II / CM cement typically comprises 50 to 64% by weight of clinker, and at least two other constituents selected from blast furnace slag, pozzolan, fly ash, calcined clay, and limestone.

[0034] In some embodiments, the cement is a CEM III / A, CEM III / B, or CEM III / C blast furnace slag cement of EN 197-1. The CEM III / A cement comprises 35 to 64% by weight of clinker and 36 to 65% by weight of clinker. blast furnace. CEM III / B cement comprises 20 to 34% by weight of clinker and 66 to 80% by weight of blast furnace slag. CEM III / C cement comprises 5 to 19% by weight of clinker and 81 to 95% by weight of blast furnace slag.

[0035] In some embodiments, the cement is a CEM V / A or CEM V / B slag composite cement of EN 197-1. The CEM V / A cement comprises 40 to 64% by weight of clinker, 18 to 30% by weight of blast furnace slag and 18 to 30% by weight of pozzolan or fly ash. The CEM V / B cement comprises 20 to 38% by weight of clinker, 31 to 49% by weight of blast furnace slag and 31 to 49% by weight of pozzolan or fly ash.

[0036] In some embodiments, the cement is a CEM VI slag pozzolanic cement of the EN 197-5 standard, in particular a CEM VI (SP), CEM VI (SV), CEM VI (SL) cement. The CEM VI (SP, V or L) cement comprises 35 to 49% by weight of clinker, 31 to 59% by weight of blast furnace slag and 6 to 20% by weight of pozzolans, fly ash or limestone.

[0037] In certain embodiments, the cement is a mixture comprising (preferably consisting of) CEM I Portland cement and a blast furnace slag, the weight content of CEM I Portland cement preferably being from 5 to 64% (or even from 20 to 50%) relative to the weight of the mixture.

[0038] In certain embodiments, the cement is a mixture comprising (preferably consisting of) CEM I Portland cement, silica fume and a blast furnace slag, the weight content of CEM I Portland cement preferably being 30 to 60% (or even 40 to 60%) relative to the weight of the mixture and the weight content of silica fume preferably being 5 to 35% (or even 10 to 30%) relative to the weight of the mixture.

[0039] In certain embodiments, the cement is a mixture comprising (preferably consisting of) CEM I Portland cement or CEM III / B cement, and silica fume, the weight content of CEM I Portland cement or CEM III / B cement preferably being 50 to 94% (or even 60 to 80%) relative to the weight of the mixture.

[0040] In some embodiments, the cement is a mixture comprising:

[0041] - a cement as defined by standard EN 197-1 or standard EN 197-5 (for example a CEM I or CEM III / B cement), and

[0042] - an addition having a Blaine specific surface area of ​​at least twice the surface area specific to the cement of said mixture.

[0043] The Blaine specific surface area of ​​the addition is advantageously greater than 0.6 m 2 / g, for example greater than 0.8 m2 / g, greater than 1.0 m2 / g, greater than 1.2 m2 / g, and preferably less than 5 m2 / g. The addition typically consists of inorganic particles, in particular SiO2, the inorganic particles being finer and / or less dense than the cement of said mixture. More particularly, the addition may comprise (or even consist of) one or more of the following compounds: diatomite, moler, expanded perlite, andalusite, bentonite, chamotte, activated carbon, biochar, feldspar, graphite, graphene, halloysite, kaolin, mica, molochite, mullite, carbon black, talc or wollastonite.

[0044] The Blaine specific surface area is determined according to the Blaine method (defined by standard NF EN 196-6).

[0045] The cement used in the present invention may comprise secondary constituents in a content of less than 5% by weight. The secondary constituents are as defined in standard EN197-1 or EN 197-5. Specifically, they are generally compounds which derive from the clinker production process, or blast furnace slag, fly ash, pozzolan, silica fume, limestone, or calcined clay.

[0046] In a preferred embodiment, the cement is a CEM III / B cement of standard EN 197-1.

[0047] The cement weight content (based on its dry weight) is advantageously from 15 to 60%, for example from 20 to 60%, preferably from 25 to 50%, or even from 25 to 45%, relative to the total dry weight of the mortar composition.

[0048] The mortar composition further comprises a magnesium-based additive.

[0049] The cement may include magnesium in its composition. It is understood that said additive is distinct from the cement, and more particularly distinct from the magnesium compounds possibly present in the cement.

[0050] The magnesium-based additive may be organic or inorganic.

[0051] Examples of organic magnesium-based additives include magnesium carboxylates, such as magnesium acetate, magnesium lactate, magnesium malate, or magnesium citrate.

[0052] However, it is preferred that the magnesium-based additive be inorganic.

[0053] In some embodiments, the magnesium-based additive is selected from a magnesium halide (e.g., magnesium chloride, magnesium bromide), a magnesium hypohalite (e.g., magnesium hypochlorite), a magnesium perhalogenate (e.g., magnesium perchlorate), a magnesium sulfate, a magnesium carbonate, a magnesium silicate, a magnesium nitrate, a magnesium phosphate, a magnesium sulfonate, a magnesium thiosulfate, a magnesium hydroxide (e.g., a hydrotalcite or Mg(OH)2), a magnesium oxide (e.g., MgO), a hydrate thereof, and a mixture of at least two of these.

[0054] In a preferred embodiment, the magnesium-based additive is a magnesium oxide. More preferably, the magnesium-based additive is MgO.

[0055] The weight content of magnesium-based additive (based on its dry weight) is advantageously from 0.02 to 10%, for example from 0.05 to 10%, from 0.1 to 10%, from 0.2 to 10%, from 0.4 to 10%, from 0.1 to 8%, from 0.1 to 5%, from 0.2 to 5%, or from 0.4 to 3%, relative to the total dry weight of the mortar composition. When said additive is a hydrate, it is understood that the reference weight for the weight content is that of the hydrate and not of the corresponding anhydrous compound.

[0056] Typically, the mortar composition further comprises mineral fillers. Preferably, the mineral fillers are chosen from fillers, sand, gravel, or a mixture of at least two of these.

[0057] By “filler” we mean in particular fines, or addition fines, that is to say a fine aggregate.

[0058] The sand and gravel are preferably of a siliceous or calcareous nature.

[0059] Advantageously, at least 95% by mass of the charges have a diameter less than or equal to 8 mm. Such a diameter can be measured according to standard EN 933-1, using the test for determining the geometric characteristics of aggregates (Part 1: Determination of granularity - Granulometric analysis by sieving).

[0060] The mass ratio of the quantity of mineral fillers to the quantity of dry cement is preferably from 0.5 to 5, or even from 1 to 4, or even from 1.5 to 3.

[0061] Typically, the mortar composition further comprises water. The mass ratio of the amount of water to the amount of dry cement is preferably 0.2 to 1, or even 0.3 to 0.6, or even 0.35 to 0.5.

[0062] In certain embodiments, the mortar composition further comprises one or more adjuvants. The adjuvants may be organic or mineral. Examples include setting (or hardening) accelerators, setting retarders, viscosity modifiers, and superplasticizers.

[0063] A superplasticizer has the role of increasing the fluidity of the mortar composition at constant water dosage or of reducing the water content at constant fluidity. The superplasticizer may for example be a polycarboxylate solution advantageously having a dry extract of 10 to 50%, preferably 20 to 35%.

[0064] The mass ratio of the quantity of adjuvant(s) to the quantity of dry cement is preferably from 0.0001 to 0.1, for example from 0.0001 to 0.05, or even from 0.0005 to 0.04, or even from 0.001 to 0.03.

[0065] It is understood that the magnesium-based additive is not encompassed by the term “adjuvant” used in the present application.

[0066] [Fig.l] is a schematic cross-sectional representation of a coated pipeline or tank element, in a particular embodiment of the invention. In this embodiment, the coated pipeline or tank element 10 comprises:

[0067] - a raw pipe or tank element 12 made of ductile iron, steel or concrete,

[0068] - an inner coating 18 located on an inner wall 14 of the channel element raw tank 12, the inner lining 18 being formed from a mortar composition as defined in the present application, and

[0069] - advantageously, an exterior covering 20 located on an exterior wall 16 of the raw pipe or tank element 12.

[0070] The coated pipe or reservoir element 10 defines an interior space 22 in which the liquid (typically water) 5 circulates in contact with the interior coating 18.

[0071] The outer covering 20 is advantageously adapted to contact with a ground 24.

[0072] The present invention also relates to a pipeline or a tank comprising one or more coated pipeline or tank elements as defined in the present application.

[0073] The pipeline or reservoir is advantageously intended for the supply, distribution or storage of drinking water.

[0074] Examples of metals whose release can be limited by means of the inner coating of the invention include those mentioned in EU Directive 2020 / 2184. Examples include the following metals: antimony (Sb), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), manganese (Mg), mercury (Hg), nickel (Ni), lead (Pb), selenium (Se), vanadium (V), zinc (Zn), aluminum (Al), and uranium (U).

[0075] It further relates to a method of manufacturing a coated pipe or tank element as defined in the present application, comprising:

[0076] i) applying a mortar composition to an inner wall of a raw ductile iron, steel or concrete pipeline or tank element to form a wet inner lining, and

[0077] ii) curing the wet inner coating to obtain said coated pipe or tank element comprising a cured inner coating,

[0078] characterized in that the mortar composition is as defined in the present application.

[0079] The following examples illustrate the present invention, in a non-limiting manner. EXAMPLES

[0080] Test specimens were made by coating sections of cast iron pipe with a nominal diameter of 200 mm with mortar compositions of different formulations. This mortar is implemented by centrifugation at 175 G. The sand used is a siliceous sand with a grain size of 0 to 2 mm.

[0081] These specimens were tested according to the leaching protocol of standard EN 14944-3, describing the implementation of three successive migrations. The rates indicated in Table 1 below are the rates obtained at the end of the third migration. The rates indicated for the reference (i.e. without magnesium-based additive) are by default set at 100% and those indicated for the invention (i.e. with magnesium-based additive) are calculated relative to the reference.

[0082] [Tables 1] Aluminum Vanadium Antimony Reference CEM III / B (comparative) 100% 100% 100% CEM 111 / B + 0.4%* MgO (invention) 90% <59% <9% CEM 111 / B + 2%* MgO (invention) <29% <59% 40%

[0083] * weight content of MgO expressed relative to the total dry weight of the composition mortar

[0084] Table 1 demonstrates that the use of a mortar formed from a composition comprising a magnesium-based additive makes it possible to substantially reduce the levels of aluminum, vanadium, and antimony released into the water.

Claims

Claims

1. A coated pipeline or tank element (10) comprising: - a raw pipeline or tank element (12) made of ductile iron, steel or concrete, and - an inner coating (18) located on an inner wall (14) of the raw pipeline or tank element (12), the inner coating (18) being formed from a mortar composition comprising: - a cement and - a magnesium-based additive.

2. A lined pipe or tank element (10) according to claim 1, characterized in that the cement is a Portland cement, a compound Portland cement, a blast furnace slag cement, a compound cement, a pozzolanic slag cement, a calcined limestone and clay cement, an aluminous cement, a sulfo-aluminous cement, a supersulfated cement, a quick-setting cement or a mixture thereof.

3. A coated pipeline or tank element (10) according to claim 1 or 2, characterized in that the cement is a cement comprising 20 to 34% by weight of clinker and 66 to 80% by weight of blast furnace slag.

4. Coated pipe or tank element (10) according to any one of claims 1 to 3, characterized in that the dry cement weight content is 15 to 60%, for example 20 to 60%, preferably 25 to 50%, or even 25 to 45%, relative to the total dry weight of the mortar composition.

5. A coated pipe or tank element (10) according to any one of claims 1 to 4, characterized in that the magnesium-based additive is selected from a magnesium halide, a magnesium hypohalite, a magnesium perhalogenate, a magnesium sulfate, a magnesium carbonate, a magnesium silicate, a magnesium nitrate, a magnesium phosphate, a magnesium sulfonate, a magnesium thiosulfate, a magnesium hydroxide, a magnesium oxide, a hydrate thereof, and a mixture of at least two of these.

6. A coated pipeline or tank element (10) according to claim 5, characterized in that the magnesium-based additive is MgO.

7. A coated pipe or tank element (10) according to any one of claims 1 to 6, characterized in that the weight content of magnesium-based additive is 0.02 to 10%, for example 0.05 to 10%, 0.1 to 10%, 0.2 to 10%, 0.4 to 10%, 0.1 to 8%, 0.1 to 5%, 0.2 to 5%, or 0.4 to 3%, relative to the total dry weight of the mortar composition.

8. A coated pipeline or tank element (10) according to any one of claims 1 to 7, characterized in that the mortar composition further comprises mineral fillers, where the mass ratio of the quantity of mineral fillers to the quantity of dry cement is preferably 0.5 to 5, or even 1 to 4, or even 1.5 to 0.

9. J. Coated pipeline or tank element (10) according to claim 8, characterized in that the mineral fillers are chosen from fillers, sand, gravel, or a mixture of at least two of these.

10. A pipeline or reservoir comprising one or more coated pipeline or reservoir elements as defined in any one of claims 1 to 9, the pipeline or reservoir preferably being intended for the supply, distribution or storage of drinking water.

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