METHOD FOR ACTIVATION OF ALUMINUM-CONTAINING FLAMMATORY

Abstract

Method for activating aluminium-containing precipitating agents, wherein, based on 1 m² of a mineral-metal composite containing iron, chromium, nickel or copper and chromium, a quantity of precipitating agent containing 5 to 10% aluminium in the range of 0.1 l / h to 100 l / h is dosed into the water to be treated, which flows over the mineral-metal composite at a speed of 0.1 to 1 m / s, wherein the volume flow of the water is 10 to 30,000 m³ / h.

Description

The invention relates to a method for activating aluminium-containing precipitating agents. The use of acidic and basic aluminum salts (e.g., aluminum sulfate, aluminum chloride, polyaluminium chloride, sodium aluminate) is problematic in practice for several reasons: On the one hand, they represent a significant cost factor; on the other hand, their excessive use has negative environmental impacts, as residues of aluminum compounds can enter the environment. Optimizing these precipitating agents therefore offers great potential for reducing costs, minimizing environmental impact, and simultaneously increasing the efficiency of precipitation of suspended solids and dissolved particles. DE 10 2018 128 516 A1 relates to a method for reducing deposits in water-bearing systems by pumping the water with a pump whose energy input, based on the volume flow rate of the water to be pumped, is greater than its osmotic pressure plus the external pressure, wherein - viewed in the direction of flow - a mineral metal foil and / or a wire mesh containing iron(II) ions is introduced upstream of the pump, wherein the ratio of the area of ​​the foil or wire mesh to the volume flow rate of the water is between 0.01 and 1 h / m. The iron(II) ion-containing mineral-metal foil and / or wire mesh consists of a metallic alloy of 15 to 35 wt% chromium and at least 60 wt% iron + nickel, in which the weight fraction of accompanying elements, in particular manganese, molybdenum, copper and silicon, does not exceed 15 wt%. DE 10 2017 131 132 A1 discloses a method for reducing outgassing and cavitation effects during ultrasonic measurements in aqueous solutions and ultrasonic cleaning baths, in which a mineral surface is produced on a metallic alloy of 15 to 35 wt.% Cr and at least 60 wt.% Fe + Ni, in which the weight fraction of accompanying elements, in particular Mn, Mo, Cu and Si, does not exceed 15%, by means of a thermal treatment lasting 5 to 60 minutes under an oxygen-containing atmosphere at a temperature of 500 to 1,000°C, wherein the alloy is heated at a rate of 300 to 500 K per minute and cooled abruptly at a rate of at least 50 K per second, and the semiconducting, catalytically active surface thus produced is brought into contact with the water to be treated. The semiconducting, catalytically active surface layer is formed by an iron-chromium-nickel spinel. The technical challenge is to develop a process that: - significantly reduces the use of aluminium-containing precipitating agents, - increases the efficiency of precipitation of suspended solids and dissolved particles, and - makes the overall process more sustainable and economical. The solution is achieved by a process for activating aluminium-containing precipitating agents, wherein, based on 1 m² of a mineral-metal composite containing iron, chromium, nickel or copper and chromium, a quantity of precipitating agent with 5 to 10% aluminium in the range of 0.1 l / h to 100 l / h is dosed into the water to be treated, which flows over the mineral-metal composite at a speed of 0.1 to 1 m / s, with the volume flow of the water being 10 to 30,000 m³ / h. Advantageous further developments of the method according to the invention can be found in the associated dependent claims. The process according to the invention selectively activates the aluminum-containing precipitating agent in combination with a mineral-metal composite. The interaction between the precipitating agent and the special metal surface enhances the precipitation effect, thereby requiring fewer aluminum salts to achieve comparable or better results. The mineral-metal composite used has an Fe-Cr-Ni spinel structure on the surface, which is based on an Fe-Cr-Ni alloy with almost equal proportions of Fe, Cr and Ni. Alternatively, the mineral-metal composite used can consist of a copper-chromium spinel on the surface, which is applied to a copper-chromium-zirconium alloy, the alloy containing 0.5 to 5 wt% chromium and 0.025 to 0.5 wt% zirconium, with the remainder being copper. The mineral-metal composite used in each case consists of a foil with a thickness of 10 to 100 µm. Alternatively, the mineral-metal composite could consist of a wire with a diameter of 0.1 to 5 mm. The proposed method for activating aluminum-containing precipitants offers an innovative solution for water and wastewater treatment. It not only enables a significant reduction in aluminum usage but also increases the efficiency and sustainability of the process. This leads to ecological and economic benefits and represents a significant advancement in water and wastewater treatment. Examples: Example 1: Reduction of aluminum salts in a wastewater treatment plant In a wastewater treatment plant, an iron-chromium-nickel-spinel metal composite in the form of a 20 µm thick foil with an area of ​​0.3 m² is installed in a distribution structure. The flow rate in the distribution structure is 10,000 m³ / d. Of this, 6,000 m³ / d is returned and 4,000 m³ / d is discharged into the receiving water body. Before the installation of the iron-chromium-nickel-spinel metal composite, an average of 20 l / h of an aluminum-containing precipitant with 6% aluminum was dosed into the return flow. The phosphate concentrations in the wastewater treatment plant effluent ranged from 0.5 to 1.0 mg / l oPO₄-P. After the installation of the iron-chromium-nickel-spinel metal composite, only 12.5 l / h of the aluminum-containing precipitant was required, while the precipitation effect was simultaneously increased. The residual phosphate content was 0.25 to 0.75 mg / l oPO4-P. Example 2: Use of aluminum salts in drinking water treatment Aluminum salts are also frequently used in water treatment plants, for example to remove unwanted dissolved and suspended substances from the raw water. Here, too, the use of an iron-chromium-nickel spinel metal composite is a suitable option. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 10 2018 128 516 A1

[0003] DE 10 2017 131 132 A1

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Claims

Method for activating aluminium-containing precipitating agents, characterized in that, based on 1 m² of a mineral-metal composite containing iron, chromium, nickel or copper and chromium, a quantity of precipitating agent with 5 to 10% aluminium in the range of 0.1 l / h to 100 l / h is dosed into the water to be treated, which flows over the mineral-metal composite at a speed of 0.1 to 1 m / s, wherein the volume flow of the water is 10 to 30,000 m³ / h. The method according to claim 1, characterized in that the mineral-metal composite has an iron-chromium-nickel spinel structure on the surface, which is based on an iron-chromium-nickel alloy with nearly equal proportions of iron, chromium and nickel. The method according to claim 1, characterized in that the mineral-metal composite on the surface consists of a copper-chromium spinel applied to a copper-chromium-zirconium alloy, wherein the alloy contains 0.5 to 5 wt% chromium and 0.025 to 0.5 wt% zirconium and the remainder copper. Method according to one of claims 1 to 3, characterized in that the mineral-metal composite consists of a foil with a thickness of 10 to 100 µm. Method according to one of claims 1 to 3, characterized in that the mineral-metal composite consists of a wire with a diameter of 0.1 to 5 mm. Use of the method according to any one of claims 1 to 5 in drinking water treatment. Use of the method according to any one of claims 1 to 5, for the reduction of aluminium salts in wastewater treatment, in particular in a sewage treatment plant.