DE19927907B4 - Process and apparatus for purifying acidic, iron and sulphate mining waters - Google Patents

Abstract

Process for the purification of acidic, ferrous and sulphate mining waters using the High Density Sludge method (HDS method), whereby the miners' waters to be treated contain elevated concentrations of uranium up to 50 mg / l, its derivatives, a high sulphate content of up to 5 g / l, rock-specific metal ions, in particular iron, and have a low pH between 2 and 4,
in which the cleaning of the mining waters with respect to the uranium, its secondary products and / or the sulphate contaminants and metal contaminations in a one-step process according to the HDS method with addition of precipitant (6) and / or barium chloride (7),
and the raw water to be purified from a distribution box (2) via one or more inlet nozzles (3), which work in cooperation with a sprayer (19) according to the water jet pump principle, in free fall in a first chamber (10) of a multi-chamber reaction pool (9 ),
At the same time, a recycled sludge return line (5), which was previously mixed with precipitant (6) in a conditioning tank (8), is introduced into the first chamber (10), and whereby the liquid ...

Description

The The invention relates to a method and a device for cleaning acidic, iron- and sulphate-containing mining waters caused by increased concentrations of uranium up to 50 mg / l, its derivatives, a high sulphate content up to 5 g / l, rock-specific metal ions, in particular iron, and a low pH between 2 and 4 are characterized. These mining waters to be cleaned fall especially in the flooding of mines where mining operated by sulphurous leaching of the ore-containing rock was or by oxidation of sulfidic ores, to.

The purification of approximately neutral mining waters with the separation of uranium and radium compounds is known DE 43 22 663 A1 , An organic polymer aggregate with amidoxime and hydroxamic acid structures is used here DE 40 16 543 A1 is known. Both the low pH in the inlet as well as the accumulation of organic precipitated sludge and the entry of chloride ions in the process (via FeCl ₃ additions) make this process seem practically inappropriate.

In DE 43 13 127 A1 the separate separation of arsenic, uranium and radium from mining waters by means of hydrogen peroxide, ferric ions, phosphoric acid and milk of lime is proposed. In addition to the considerable input of chloride and phosphate in the process, the pH must be adjusted twice with milk of lime, so that a total high chemical consumption (up to 200 g / m ^{3 of} phosphorus and up to 280 g / m ^{3 of} chloride) is required.

In DE 43 07 468 A1 It is proposed to use the constituents of rubble for the binding of uranium and other contaminants in waters of mining refurbishment, which at high uranium concentrations up to 220 g of rubble per liter of water to be purified are required. In addition, considerable amounts of construction waste accumulate in this process, which have to be disposed of and disposed of.

The use of sulphides for the separation of radioactive heavy metals is in DE 27 14 202 C2 described and also used in practice for the purification of heavy metal-containing waters of mine drainage (Larsen, HP, Ross, LW: Operating Handbook of Mineral Processing, 1976, 5.349). The use of sulfides is problematic because of their water polluting properties and requires the use of other precipitants for setting the sulfide excess.

Generally the treatment of acidic, metal-containing waters is known Calcium hydroxide, whereby many metals are precipitated hydroxides can. In the report NLJREG / CR-3906, PNL-5179 (Opitz, B.E., Dodson, M. e .; Serne, R.J .: Pacific Northwest Laboratory, Richland, WA, May 1985), laboratory experiments on the alternative use of calcium hydroxide, Calcium carbonate and a mixture of calcium hydroxide and sodium bicarbonate for precipitation the constituents of acidic, uranium-containing waters from treatment plants and settling tank described. Disadvantages of this process are in addition the need for great Settling tank for process implementation, the high cost at the mud clearing / disposal and the formation of plaster incrustations.

In The practice of iron ore mining is further the so-called HDS method (High Density Sludge) for treatment mine drainage applied. The specific of this method is that the strong gypsum-containing precipitated sludges Thickeners are recycled to the inlet of the neutralizing agent.

The Treatment of mining waters with lime for precipitation of iron hydroxide and gypsum with their subsequent sedimentation in open earth or concrete tanks, inclined clarifiers or round thickeners Krälwerk belongs to the Standard techniques of water purification (Hartinger, L .: Handbuch der Wastewater treatment for the metalworking industry. Hanser-Verlag Munich, Vienna 1976; Hartinger L .: Handbook of wastewater and recycling law. Hanser-Verlag Munich, Vienna 1995; Teaching and Handbook of Wastewater Technology. 3. Edition; publishing company Ernst &Son; Berlin 1983; Graef, R .; Hartinger, L .; Lohmeyer, S .; Schwering H.-U .: Wastewater technology in production - WEKA Praxishandbuch. WEKA Fachverlag, Augsburg 1993/1999).

The achievable surface loads of the sedimentation basins are generally below 0.5 m ³ / (m ² h), resulting in high expenses for the construction of correspondingly large basins as well as for sludge clearing and drainage.

• – hoher Flächendurchsatz und damit relativ geringe Dimensionen der Eindicker,
• – geringer Chemikalienverbrauch,
• – gute Entwässerbarkeit der Fällschlämme und
• – weitgehende Vermeidung von Gipsverkrustungen an Anlagenteilen.

The invention is based on the object, an effective, cost-effective method with minimized use of water pollutants as adsorption or precipitant, consistent Reinigungseffek to develop over a longer period of time, a high degree of purification of uranium and its derivatives, and a simple and reliable apparatus for the purification of mining waters with the following advantages:

• High surface throughput and thus relatively small dimensions of the thickener,
• - low consumption of chemicals,
• - good drainability of the precipitated sludge and
• - extensive avoidance of gypsum encrustations on system components.

simultaneously are the residues for the environment is safe and with low load on the operating staff to dispose of and a the prescribed limits corresponding Deliver clean water to the receiving water.

This object is achieved in that the purification of the mining waters with respect to the uranium, its derivatives and / or the sulphate contaminants and metal contamination in a one-step process according to the HDS method with the addition of precipitants lime and / or barium chloride, wherein the raw water to be purified from a distribution box via one or more inlet nozzles, which work in conjunction with an atomizer according to the water jet pump principle, falls in free fall into the first chamber of the multi-chamber reaction pool. At the same time in the first chamber, the recycled sludge return, which was previously mixed in a conditioning tank with precipitant introduced, the raw water aerated by the free fall and the recycled sludge return to iron and manganese oxidation at a mean time of 10 to 30 minutes in the Chambers of the multi-chamber reaction tank dwells before overflow into the guide tube, each chamber separately with precipitant, with further aeration of the raw water, fed and in terms of pH by Fällmitteldosierung the pH gradually to 7.5 to 8.5 in .DELTA 1 to 2.5 is increased. By adding barium chloride (BaCl ₂ ) in the multi-chamber reaction pool, the co-precipitation of radium from the raw water to be purified takes place, the solid / liquid separation with the addition of flocculants in a stable fluidized bed of metal hydroxide-gypsum particles (flakes) in a Hochleistungsseindicker expires, the majority of the deduction sludge drawn off at the sludge outlet of the high-performance thickener in control and regulation of the sludge in the process under renewed, pH-controlled addition of precipitant and mixture with the raw water over 10 times and the proportion of withdrawn from the process, easily drained, inorganic precipitation sludge is disposed of without intermediate storage.

By one over 10-fold recycle of the precipitate at the sludge outlet is an easily dewaterable metal hydroxide gypsum sludge, the felled Includes links of uranium and its derivatives, with a proportion of solids over 10 M% with continuous draw and up to more than 30 M% with discontinuous Deduction discharged.

Of the accumulating inorganic precipitation sludge is using conventional Binders immobilized and after curing, an immobilizate high strength and low elution of trapped pollutants deposited under real elution conditions.

The device for carrying out the method for the purification of acidic, iron and sulphate mining waters according to the invention is designed so that the inflow of mining waters to be purified from a distribution box above the multi-chamber reaction tank in free fall via one or more inlet nozzles with different lengths, due to different integration lengths of Inlet nozzles in the distribution box, wherein the diameter of the inlet nozzle in the inlet diameter ratio of the inlet nozzle: exit diameter of the inlet nozzle equal to 1.5 to 2.5: 1 and at the outlet of each inlet nozzle, a nebulizer with air inlet openings and / or inside a nebulizer is mounted in the first chamber of the multi-chamber reaction tank according to the water jet pump principle, the multi-chamber reaction tank consists of at least two chambers to be ventilated, the volume of the respective chamber through the required residence time to clean raw water is determined, and the overflows are arranged offset between the chambers in the intermediate walls, that the cross-sectional areas of the inlet tube, the guide tube, which has a constriction shortly before exiting, and the high-performance thickener in the cross-sectional area of the inlet tube (A ₀ ) of the guide tube (A ₁ ): cross-sectional area of the guide tube at the constriction (A ₂ ): cross-sectional area of the guide tube at the outlet (A ₃ ): cross-sectional area of the high-performance thickener (A ₄ ) is 0.05 to 0.2: 1: 0.3 to 0.7: 0.5 to 0.9: 5 to 9, wherein the upper sludge level between at least 1.5 m above the trailing edge of the guide tube to 0.5 m below the overflow edge of the clear water outlet varies and the absolute size of the cross-sectional area of the Hochleistungsseindickers (A ₄ ) is the nominal flow rate of the plant adapt.

A constant level height of the mining water to be cleaned in the distribution box is controlled by the number of inlet nozzles, the dimensioning of the inlet diameter (D ₃ ) of the inlet nozzle and the outlet diameter (D ₄ ) of the inlet nozzle and the different insertion lengths (L _e ) of the inlet nozzles.

Schema 1: Prinzipskizze des Verfahrens The principle of the method and apparatus for the purification of mining waters is shown in Scheme 1.

Scheme 1: Schematic diagram of the procedure

• – Die Fest/Flüssig-Trennung erfolgt in einem stabilen Schwebbett aus Metallhydroxid-Gips-Partikeln. Das bedeutet, die dem Hochleistungseindicker zufließende Suspension wird gleichmäßig unter die Arbeitszone verteilt. Beim Aufstieg wird die Schlammbettzone passiert, der Feststoff abgebremst und feine Bestandteile an den Partikeln des Schwebbetts adsorbiert. Nur ausreichend große Flocken sedimentieren aus der Schwebebett in die Verdichtungszone. Die Wirkungsweise ist somit als Kopplung von Filtration und Sedimentation charakterisiert. In diesem Filtrations- und Sedimentationsprozeß werden bis über 95 % der Anteile von Uran und seinen Folgeprodukten aus dem zu reinigenden Wasser entfernt und fest an die sedimentierenden Flocken gebunden.
• – Neu ist die Kopplung der HDS-Methode mit einer Fest/Flüssig-Trennung nach dem Hochleistungseindicker-Prinzip. Durch das Verhältnis der Querschnittsflächen des Einleitungsrohres, des Leitrohres und des Hochleistungseindickers wird das Schwebbett erzeugt und gleichzeitig ein hoher Flächendurchsatz erzielt.
• – Der Schlammrücklauf wird vor dem Einleiten ins Mehrkammerreaktionsbecken konditioniert. Dem Hochleistungseindicker wird ständig die 10- bis 20fache Menge des neu gebildeten Schlammes entnommen und rezykliert. Nur 5 bis 10 % des anfallenden Schlammes werden aus dem Prozeß ausgeschleust. Der rezyklierte Schlammrücklauf wird im sogenannten Konditionierungstank intensiv mit dem Fällmittel gemischt, dabei übersättigt und danach erst dem Mehrkammerreaktionsbecken zugeführt. Die Fällmitteldosierung wird über den pH-Wert des Konditionierungstanks gesteuert. Damit erfolgt die Feststoffneubildung überwiegend an der übersättigten Feststoffoberfläche und nicht an Apparateteilen (Gipsverkrustung), d. h. der erhöhte Austrag von Uran und seinen Folgeprodukten bleibt an den Partikeln des Metallhydroxid-Gips-Schlamms gebunden.
• – Die Ausfällung von Radium erfolgt im Mehrkammerreaktionsbecken mittels Zugaben von Bariumchlorid (BaCl₂), wobei der hohe Sulfatgehalt des Rohwassers zur Co-Fällung des Radiums mit Bariumsulfat führt und der Bariumaustrag in das Reinwasser zu vernachlässigen ist. Die Vorteile der vollständigen Chemikaliennutzung infolge Schlammrezyklierung gelten auch für Bariumchlorid.
• – Die Einstellung eines stationären Schlamm-Schwebbetts im Hochleistungseindicker ermöglicht die Realisierung eines kontinuierlichen Schlammabzuges aus dem Verfahren. Ohne nochmalige Zwischenlagerung läßt sich nach einer über 10fachen Rezyklierung des Fällproduktes und einem kontinuierlichen Schlammabzug ein leicht entwässerbarer Metallhydroxid-Gips-Schlamm mit einem Feststoffanteil über 10 M% bzw. bis über 30 M% bei diskontinuierlichem Schlammabzug mittels Dekanter sowie Dickstoffpumpen und -leitungen bis zum Ort der Verwahrung der Fällschlämme (Bergehalde) austragen. Damit entfallen die arbeitsintensiven Prozesse der Schlammberäumung aus Absetzbecken und der Schlammentwässerung mittels Filterpresse.
• – Durch Mischung des anfallenden anorganischen Fällschlammes mit herkömmlichen Bindemitteln (Zement, Kalkhydrat, Aschen u. a.) kann unmittelbar am Verwahrungsort ein mechanisch stabiles, rein anorganisches Immobilisat erzeugt werden, in dem die radioaktiven und sonstigen Schadstoffe dauerhaft und elutionsstabil eingeschlossen sind. Vor seiner Aushärtung wird das Immobilisat an den Ort seiner endgültigen Verwahrung (Bergehalde) befördert und deponiert.
• – Über das Einleitungsrohr erfolgt der tangentiale Einlauf der zu reinigenden Bergbauwässer aus dem Mehrkammerreaktionsbecken in das Leitrohr, so daß sich die beträchtliche Einlaufgeschwindigkeit (v₀) in eine Rotationsbewegung der Flüssigkeit umsetzt, während sich die vertikale Geschwindigkeitskomponente v₁ = Q_R/A₁ im Leitrohr praktisch aus der Rohwassereinlaufmenge pro Zeiteinheit (Q_R) und den Querschnittsflächen des Leitrohres (A₁) ergibt. Wegen des Verhältnisses der Querschnittsflächen A₀:A₁ = 0,05 bis 0,2:1 ergibt sich eine starke Reduzierung der mittleren vertikalen Geschwindigkeitskomponente (v₁) im Leitrohr, wobei das Leitrohr mindestens 1,5 m bis unter den Schlammpegel reicht. Durch eine Einschnürung im Leitrohr erhöht sich die vertikale Geschwindigkeitskomponente (v₂) in der engsten Stelle des Leitrohrs auf v₂ = v₁ (A₁/A₂) bei einem Verhältnis von A₁:A₂ = 1:0,3 bis 0,7 und erhält nachfolgend eine radiale Geschwindigkeitskomponente durch Erweiterung des Querschnitts auf A₃ bei einem Verhältnis von A₁:A₃ = 1:0,5 bis 0,9. Unterstützt durch einen Prallkegel und den Staudruck des Mediums im unteren Teil des Hochleistungseindickers kommt es zur Umkehr der Bewegungsrichtung der Bergbauwässer und infolge der starken Querschnittserweiterung zu einer Reduzierung der vertikalen Geschwindigkeitskomponente auf v₄ = v₁(A₁/A₄) bei einem Verhältnis von A₁:A₄ = 1:5 bis 9.
• – Die Funktionsfähigkeit des Hochleistungseindickers beruht darauf, daß die mittlere Aufstiegsgeschwindigkeit (v₄) geringer als die Sinkgeschwindigkeit (v_S) der Partikel des Schlammbettes ist. Dadurch bildet sich eine Schwebbettzone aus, in der die von den zu reinigenden Bergbauwässern mitgetragenen Metallhydroxid-Gips-Partikel gefiltriert werden, so daß sich eine relativ scharfe horizontale Trenngrenze zwischen Schlamm (Feststoff) und Klarwasser ausbildet.
• – Je nach Zusammensetzung und Konzentration der Schadstoffe im Rohwasser, der Konzentration von Flockungshilfsmitteln sowie dem Neutralisationsprozeß, können Flächenbelastungen des Hochleistungseindickers von 1 bis 10 m³/m² h erreicht werden (Flächenbelastung ist der Durchsatz [m³/h] pro Flächeneinheit [m²], d. h. er entspricht der Aufstiegsgeschwindigkeit v₄ [m/h]). Bei bekannter Sinkgeschwindigkeit (v_S) der Metallhydroxid-Gips-Partikel kann die Dimensionierung der Vorrichtung ermittelt werden, wobei die Sinkge schwindigkeit (v_S) selbst in komplexer Weise sowohl vom zu reinigenden Medium als auch von der Neutralisationstechnologie abhängig ist.
• – Die Höhe der Schwebbettzone bzw. des Schlammpegels (H_S) über der Austrittskante des Leitrohres beträgt mindestens 1,5 m, um eine sehr gute Filtration des Klarwassers und Feststoffgehalte über 10 M% bei kontinuierlichem Abzug zu erreichen. Sie kann darüber jedoch variieren, praktisch bis 0,5 m unter der Überlaufkante des Klarwasserablaufs. Somit kann der Hochleistungseindicker über längere Zeit im "Speicherbetrieb" arbeiten, d. h. ohne Schlammabzug aus dem Kreislauf gefahren werden, wobei sich eine langsam steigende Verdichtung des Schlamms im Bereich des Abzugskegels des Hochleistungseindickers ergibt und Feststoffgehalte bis über 30 M% durch diesen diskontinuierlichen Abzug erreicht werden.
• – Aus dem Verteilerkasten oberhalb des Mehrkammerreaktionsbeckens fällen die zu reinigenden Bergbauwässer im freien Fall über eine oder mehrere Einlaufdüsen (Batterie), die im Zusammenwirken mit einem Zerstäuber nach dem Wasserstrahlpumpen-Prinzip funktionieren, in die erste Kammer des Mehrkammerreaktionsbeckens, wobei erhebliche Mengen an Luft durch Sogwirkung zur Eisen- und Manganoxidation eingetragen werden.
• – Die Einlaufdüsen weisen zur Erhöhung der Einlaufgeschwindigkeit eine Reduzierung des Durchmessers auf. Die Anzahl der Einlaufdüsen, das Verhältnis von Eintrittsdurchmessers (D₃) und Austrittsdurchmesser (D₄) der Einlaufdüse sowie die unterschiedlichen Einbindelängen (L_e) der Einlaufdüsen werden so dimensioniert, daß der zulaufende Rohwasserstrom im Verteilerkasten eine konstante Pegelhöhe (H_P) erreicht. Schwankungen der Zulaufmenge werden durch unterschiedliche Einbindungslängen (L_e) der Einlaufdüsen im Verteilerkasten ausgeglichen, wodurch einerseits das Überlaufen des Verteilerkastens verhindert und andererseits auch bei geringeren Einlaufmengen die volle Sogwirkung zur Belüftung ausgenutzt wird. Bei einer möglichen Verstopfung einzelner Einlaufdüsen werden andere Einlaufdüsen bei gleicher Wirkungsweise aktiv.
• – Das Mehrkammerreaktionsbecken ist in mindestens zwei zu belüftende Kammern geteilt. Das Volumen der jeweiligen Kammer wird durch die erforderliche Verweilzeit der zu reinigenden Bergbauwässer vor Überlauf in das Leitrohr bestimmt, wobei die mittlere Verweilzeit 10 bis 30 Minuten je Kammer beträgt. Die Überläufe zwischen den Kammern in den Zwischenwänden sind so gestaltet und versetzt angeordnet, daß Kurzschlußströmungen vermieden werden. Die Kammern werden getrennt mit Fällmittel beschickt und hinsichtlich des pH-Wertes durch automatisch geregelte Fällmitteldosierung kontrolliert, um durch eine stufenweise Erhöhung des pH-Wertes auf 7,0 bis 8,5 in Schritten Δ pH von 1,0 bis 2,5 optimale Bedingungen für das Kornwachstum der Metallhydroxid-Gips-Partikel zu schaffen und den Anteil amorpher Metallhydroxidanteile im Fällschlamm zu reduzieren. Im Ergebnis wird eine höhere Feststoffdichte im Fällschlamm bei geringerer Rezyklierrate des Schlammrücklaufs erreicht. Durch Zugabe von Bariumchlorid (BaCl₂) in das Mehrkammerreaktionsbecken erfolgt die Co-Fällung von Radium aus dem sulfathaltigen Medium, welches in die Struktur der Metallhydroxid-Gips-Partikel eingebunden und damit ausgefällt wird.

The method and the device is characterized by:

• - The solid / liquid separation takes place in a stable suspended bed of metal hydroxide-gypsum particles. This means that the suspension flowing to the high-performance thickener is distributed evenly under the working zone. During the ascent, the sludge bed zone is passed, the solids are decelerated and fine constituents are adsorbed on the particles of the suspended bed. Only sufficiently large flakes sediment from the floating bed in the compression zone. The mode of action is thus characterized as the coupling of filtration and sedimentation. In this filtration and sedimentation process up to 95% of the shares of uranium and its derivatives are removed from the water to be purified and firmly bound to the sedimenting flakes.
• - New is the coupling of the HDS method with a solid / liquid separation according to the high-performance thickener principle. Due to the ratio of the cross-sectional areas of the inlet tube, the guide tube and the high-performance thickener, the fluidized bed is generated and at the same time a high surface throughput is achieved.
• - The sludge return is conditioned before being introduced into the multi-chamber reaction tank. The high-performance thickener is constantly taken from 10 to 20 times the amount of newly formed sludge and recycled. Only 5 to 10% of the resulting sludge is discharged from the process. The recycled sludge return is intensively mixed in the so-called conditioning tank with the precipitant, thereby supersaturated and then fed to the multi-chamber reaction tank. The precipitant dosage is controlled by the pH of the conditioning tank. Thus, the formation of new solids takes place predominantly on the supersaturated solid surface and not on apparatus parts (gypsum encrustation), ie the increased discharge of uranium and its secondary products remains bound to the particles of the metal hydroxide-gypsum sludge.
• - The precipitation of radium is carried out in multi-chamber reaction tank by adding barium chloride (BaCl ₂ ), the high sulfate content of the raw water leads to co-precipitation of the radium with barium sulfate and the barium discharge into the pure water is negligible. The benefits of full chemical utilization due to sludge recycle also apply to barium chloride.
• - The setting of a stationary sludge floating bed in the high-performance thickener allows the Rea tion of a continuous sludge removal from the process. Without repeated storage can be after a more than 10fachen recycling of the precipitate and a continuous sludge a slightly dewatered metal hydroxide gypsum sludge with a solids content of 10 M% and above 30 M% in discontinuous sludge removal by decanters and sludge pumps and lines up to Place the custody of the precipitation sludge (mountain dump). This eliminates the labor-intensive processes of sludge removal from settling tanks and sludge dewatering by means of a filter press.
• - By mixing the resulting inorganic precipitation sludge with conventional binders (cement, hydrated lime, ashes, etc.) can be produced directly at the repository a mechanically stable, purely inorganic immobilizate, in which the radioactive and other pollutants are permanently and elution-stable included. Before its curing, the immobilisate is transported to the place of its final storage (dump) and deposited.
• The tangential inlet of the mining waters to be cleaned from the multi-chamber reaction basin into the guide tube takes place via the inlet tube, so that the considerable inlet velocity (v ₀ ) converts into a rotational movement of the liquid, while the vertical velocity component v ₁ = Q _R / A ₁ im Guide tube practically from the raw water intake per unit time (Q _R ) and the cross-sectional areas of the guide tube (A ₁ ) results. Because of the ratio of the cross-sectional areas A ₀ : A ₁ = 0.05 to 0.2: 1, there is a strong reduction in the mean vertical velocity component (v ₁ ) in the draft tube, with the draft tube reaching at least 1.5 m below the mud level. By a constriction in the guide tube, the vertical velocity component (v ₂ ) in the narrowest point of the guide tube increases to v ₂ = v ₁ (A ₁ / A ₂ ) at a ratio of A ₁ : A ₂ = 1: 0.3 to 0 , 7 and subsequently obtains a radial velocity component by extending the cross-section to A ₃ at a ratio of A ₁ : A ₃ = 1: 0.5 to 0.9. Supported by an impact cone and the back pressure of the medium in the lower part of the high-performance thickener, the direction of movement of the mining waters reverses and, due to the strong cross-sectional expansion, the vertical velocity component is reduced to v ₄ = v ₁ (A ₁ / A ₄ ) at a ratio of A ₁ : A ₄ = 1: 5 to 9.
• The performance of the high-performance thickener is based on the fact that the average rate of ascent (v ₄ ) is less than the rate of descent (v _S ) of the particles of the sludge bed. This forms a Schwebbettzone in which the metal hydroxide-gypsum particles carried along by the mining waters to be cleaned are filtered, so that a relatively sharp horizontal separation boundary between sludge (solid) and clear water is formed.
• Depending on the composition and concentration of pollutants in the raw water, the concentration of flocculation aids and the neutralization process, surface loads of the high-performance thickener of 1 to 10 m ³ / m ² h can be achieved (surface load is the throughput [m ³ / h] per unit area [m ² ], ie it corresponds to the ascent rate v ₄ [m / h]). With a known rate of descent (v _S ) of the metal hydroxide gypsum particles, the sizing of the device can be determined, the Sinkge speed (v _S ) is even in a complex manner depending on both the medium to be cleaned and the neutralization technology.
• - The height of the silt bed zone or the sludge level (H _S ) above the outlet edge of the guide tube is at least 1.5 m, in order to achieve a very good filtration of the clear water and solid contents above 10 M% with continuous withdrawal. However, it can vary over this, practically up to 0.5 m below the overflow edge of the clear water drain. Thus, the Hochleistungsseindicker can work for a long time in the "storage mode", ie driven without sludge discharge from the circulation, resulting in a slowly increasing compression of the sludge in the range of the Abzugkegels the Hochleistungsseindickers and solids contents up to 30 M% are achieved by this discontinuous withdrawal ,
• - From the junction box above the multi-chamber reaction pool to be cleaned mining water in free fall via one or more inlet nozzles (battery), which work in conjunction with a nebulizer according to the water jet pump principle, in the first chamber of the multi-chamber reaction tank, with significant amounts of air through Suction effect for iron and manganese oxidation can be registered.
• - The inlet nozzles have a reduction of the diameter to increase the inlet velocity. The number of inlet nozzles, the ratio of inlet diameter (D ₃ ) and outlet diameter (D ₄ ) of the inlet nozzle and the different insertion lengths (L _e ) of the inlet nozzles are dimensioned so that the incoming raw water flow in the distribution box reaches a constant level level (H _P ). Fluctuations in the feed rate are compensated by different integration lengths (L _e ) of the inlet nozzles in the distribution box, which on the one hand prevents the overflow of the junction box and on the other hand, the full suction effect is utilized for ventilation even at lower inlet quantities. With a possible blockage of individual inlet nozzles, other inlet nozzles become active with the same mode of action.
• - The multi-chamber reaction pool is divided into at least two chambers to be ventilated. The volume the respective chamber is determined by the required residence time of the mining waters to be cleaned before overflow into the draft tube, the mean residence time is 10 to 30 minutes per chamber. The overflows between the chambers in the intermediate walls are designed and staggered so that short circuit flows are avoided. The chambers are fed separately with precipitant and controlled in terms of pH by automatically controlled Fällmitteldosierung to optimal conditions by gradually increasing the pH to 7.0 to 8.5 in steps Δ pH 1.0 to 2.5 to provide for the grain growth of the metal hydroxide gypsum particles and to reduce the proportion of amorphous metal hydroxide in the precipitation sludge. As a result, a higher solids density is achieved in the precipitation sludge with a lower recycle rate of the sludge return. By adding barium chloride (BaCl ₂ ) in the multi-chamber reaction tank, the co-precipitation of radium from the sulfate-containing medium, which is incorporated into the structure of the metal hydroxide gypsum particles and thus precipitated.

embodiment 1

in the The following will be an embodiment of the invention explained in more detail with reference to drawings. Show it:

1 schematic representation of the device with distribution box, multi-chamber reaction tank and high-performance thickener with guide tube (without crater),

2 Distribution box with inlet nozzles and

3 Inlet nozzle.

The Example describes a pilot plant using automatic PC control Operation as well as the constant Parameter documentation allows, in the one operating solution (Reich solution) of a refurbishment of uranium mining.

The pilot plant according to 1 consists of a distribution box 2 ( 2 ) with raw water intake 1 , Inlet nozzles 3 different total lengths ( 3 ) with atomizer 19 as well as an overflow 4 , a conditioning tank 8th , a multi-chamber reaction tank 9 with three chambers 10 and the staggered overflows 11 between the chambers 10 and a high performance thickener 14 (without crusher) with inlet pipe 12 , Guide tube 13 with constriction shortly before the exit, baffle cone 15 , Mud deduction 16 and clear water drain 17 , The mud return 5 gets over the conditioning tank 8th with the addition of the precipitant 6 (Lime milk) in the first chamber 10 of the multi-chamber reaction pool 9 recycled. In every chamber 10 of the multi-chamber reaction pool 9 the addition of precipitant occurs 6 and aeration. The last chamber is barium chloride 7 added.

• – Einleitungsrohr 12 A₀ = 9 cm²,
• – Leitrohr 13 A₁ = 87 cm²; vertikale Geschwindigkeitskomponente v₁ = 1,000 m/h,
• – Leitrohr 13 an der Einschnürung A₂ = 28 cm²; vertikale Geschwindigkeitskomponente v₂ = 3,060 m/h,
• – Leitrohr 13 am Austritt A₃ = 66 cm²; vertikale Geschwindigkeitskomponente v₃ = 1,362 m/h,
• – Hochleistungseindicker 14 A₄ = 620 cm²; vertikale Geschwindigkeitskomponente v₄ = 0,140 m/h.

The following cross-sectional areas of the inlet pipe 12 , the guide tube 13 and the high-performance thickener 14 are realized at the pilot plant:

• - inlet pipe 12 A ₀ = 9 cm ² ,
• - Guide tube 13 A ₁ = 87 cm ² ; vertical velocity component v ₁ = 1.000 m / h,
• - Guide tube 13 at the constriction A ₂ = 28 cm ² ; vertical velocity component v ₂ = 3.060 m / h,
• - Guide tube 13 at the outlet A ₃ = 66 cm ² ; vertical velocity component v ₃ = 1.362 m / h,
• - high performance thickener 14 A ₄ = 620 cm ² ; vertical velocity component v ₄ = 0.140 m / h.

• – pH-Wert 2,5 am Rohwasserzulauf 1 bzw. 8,5 am Klarwasserablauf 17,
• – Fällmittel 6 Kalziumhydroxid (als 5prozentige Kalkmilch),
• – 3,5 ml Bariumchloridlösung (0,02 %) pro Liter Betriebslösung zur Radiumfällung,
• – Verweilzeit in der Neutralisation 60 min,
• – 10 ml Flockungshilfsmittellösung (0,01 prozentig) pro Liter Betriebslösung,
• – Rücklaufverhältnis des Unteraustrages des Hochleistungseindickers 14 zur Menge der zufließenden Betriebslösung 1:1,
• – Flächenbelastung des Hochleistungseindickers 14 1,7 m³/(m² h) und
• – Feststoffzusammensetzung vorwiegend Hydroxide von Eisen, Aluminium und Zink; Sulfate des Kalziums und des Bariums (inklusive Radionuklide).

The vertical speeds are relative to the rate of descent in the draft tube 13 specified. The following parameters are run:

• - pH 2.5 at the raw water inlet 1 or 8.5 at the clear water outlet 17 .
• - precipitant 6 Calcium hydroxide (as 5% lime milk),
• - 3.5 ml of barium chloride solution (0.02%) per liter radium precipitation operating solution,
• - residence time in the neutralization 60 min,
• - 10 ml of flocculant solution (0.01%) per liter of operating solution,
• - Return ratio of the sub-output of the high-performance thickener 14 to the amount of influent operating solution 1: 1,
• - Surface load of the high-performance thickener 14 1.7 m ³ / (m ² h) and
• Solid composition predominantly hydroxides of iron, aluminum and zinc; Sulfates of calcium and barium (including radionuclides).

Tabelle 1: Analysedaten In this pilot plant, the cleaning effect documented in Table 1 by the analytical data is determined aims.

Table 1: Analysis data

By gradually increasing the pH in the chambers 10 of the multi-chamber reaction pool 9 of a pH = 2.5 in the raw water feed 1 , over pH values of 4.0 and 6.0 to 8.5, the solids content in the precipitation sludge increases to over 15 M%.

There is a sharp separation between the suspended bed and clean water zones. The turbidity in the clear water drain 17 is from 20 to 40 turbidity units (TE). The deducted precipitation sludge is easily drainable. In a plate filter system filter surface loads of 0.2 m ³ / (m ² h) can be realized.

By measuring and controlling the sludge level (H _S ) 18 becomes an operating regime with continuous sludge removal 16 at constant sludge level (H _S ) 18 realized by an automatic measuring and control system.

Tabelle 2: Bruchfestigkeit der Immobilisatprobekörper aus dem Fällprodukt der Betriebslösung (BM- und Kies-Anteile beziehen sich auf die Masse der Schlammprobe)

Tabelle 3: Bruchfestigkeit der Immobilisatprobekörper aus dem Fällschlamm (BM- und Kies-Anteile beziehen sich auf die Masse der Schlammprobe) In the immobilization of the precipitate of the operating solution and the precipitation sludge cement PZ 45 and the commercial Immobilisierungsprodukt Depocrate MF (DHF) is used as an optional binder with admixture of gravel as a filler The breaking strength of Immobilisatprobekörper - after 28 days of curing - are in the Tables 2 and 3 shown.

Table 2: Breaking strength of the immobilized specimens from the precipitate of the operating solution (BM and gravel fractions refer to the mass of the sludge sample)

TABLE 3 Breaking strength of the immobilized specimens from the precipitation sludge (BM and gravel fractions refer to the mass of the sludge sample)

The minimum strength requirements according to DIN 18134 of 0.2 N / mm ² are thus exceeded in all cases. The immobilizates have sufficient buffer capacity to protect the matrix from corrosion by weakly acidic seepage.

The uranium mobility from crushed material by water is in the range of 10 ^-4 to 10 ^-3 %. The uranium leaching rate in weakly acid leachate is less than 10 ^-5 g / (cm ² d) for mixtures Nos. 1 and 2 of Table 2 and mixtures Nos. 5 to 8 of Table 3.

Embodiment 2

In a 10-m ³ / h-Kompaktwasserreinigungsanlage the cleaning of mining waters of brown coal mining was tested in a connecting ditch between two remaining holes.

The 10 m ³ / h system, which is designed as a container system, consists of two high-performance thickeners 14 with a diameter of D ₂ = 180 cm and a diameter of the guide tube 13 of D ₁ = 60 cm.

Tabelle 4: Analysedaten einer 10-m³/h-Kompaktwasserreinigungsanlage

• *) bei anschließender Kiesbettfiltration < 0,1 mg/l

The achieved cleaning values when used on site are shown in Table 4.

Table 4: Analysis data of a 10 m ³ / h compact water purification system

• *) with subsequent gravel bed filtration <0.1 mg / l

A surface load of 1.6 m ³ / (m ² h) was achieved.

With This application example is the suitability of the method and the Device also for the case occupied, if no gypsum precipitation occurs, but only iron hydroxide fails.

1

raw water inlet

2

distribution box

3

inlet nozzle

4

overflow of the distribution box

5

Sludge recirculation

6

precipitant (Milk of lime)

7

Barium chloride (BaCl ₂ )

8th

conditioning tank

9

More chamber reaction pool

10

chamber

11

overflow between the chambers

12

inlet tube

13

guide tube

14

Hochleistungseindicker

15

deflector cone

16

sludge removal

17

Clear water drain

18

sludge level

19

atomizer

D ₁

diameter guide tube

D ₂

diameter Hochleistungseindicker

D ₃

Inlet diameter inlet nozzle

D ₄

Outlet diameter inlet nozzle

A ₀ , A ₁ , A ₂ , A ₃ , A ₄

Querschriittsfläche

v ₀ , v ₁ , v ₂ , v ₃ , v ₄

velocity component

v _p

rate of descent the particle

H _p

Level height in the distribution box

H _S

Height of mud level

L _e

Integration length inlet nozzle

L

Total length inlet nozzle

Q _R

Raw water intake amount

Claims (5)

Process for the purification of acidic, ferrous and sulphate mining waters using the High Density Sludge method (HDS method), whereby the miners' waters to be treated contain elevated concentrations of uranium up to 50 mg / l, its derivatives, a high sulphate content of up to 5 g / l, rock-specific metal ions, in particular iron, and have a low pH between 2 and 4, in which the purification of the mining waters with respect to the uranium, its derivatives and / or the sulphate contaminants and metal contaminants in a one-step process according to the HDS method with addition of precipitant ( 6 ) and / or barium chloride ( 7 ), and the raw water to be purified from a distribution box ( 2 ) via one or more inlet nozzles ( 3 ) in cooperation with a nebulizer ( 19 ) operate in accordance with the principle of the water jet pump, in free fall into a first chamber ( 10 ) of a multi-chamber reaction pool ( 9 ), at the same time the first chamber ( 10 ) a recycled sludge reflux ( 5 ) previously stored in a conditioning tank ( 8th ) with precipitant ( 6 ) and wherein the raw water aerated by the free fall and the recycled sludge return ( 5 ) for iron and manganese oxidation at a mean time of 10 to 30 minutes in the chambers ( 10 ) of the multi-chamber reaction pool ( 9 ) before an overflow into a guide tube ( 13 ), each chamber ( 10 ) separated with precipitant ( 6 ), with further aeration of the raw water, and the pH is increased gradually by precipitant metering the pH to 7.0 to 8.5 in steps Δ pH of 1.0 to 2.5, and that by the addition of barium chloride ( 7 ) into the multi-compartment reaction tank ( 9 ) the co-precipitation of radium from the raw water to be purified takes place, the solid / liquid separation with the addition of flocculation aids in a stable fluidized bed of metal hydroxide-gypsum particles in a high-performance thickener ( 14 ), and the majority of the sludge ( 16 ) of the high-performance thickener ( 14 ) in the control and regulation of the sludge level ( 18 ) precipitated sludge in the process under renewed, pH-controlled addition of precipitant ( 6 ) and mixture with the raw water over 10 times recycled and the proportion of withdrawn from the process, easily dewatered, inorganic Fällschlamms without intermediate storage is disposed of. A method according to claim 1, characterized in that at more than 10facher recycling of the precipitate on the sludge ( 16 ) an easily dewaterable metal hydroxide gypsum slurry that firmly entraps the precipitated compounds of uranium and its derivatives, with a solids content above 10 M% with continuous stripping and above 30 M% with discontinuous stripping. Method according to one of claims 1 or 2, characterized that the resulting inorganic precipitation sludge with conventional Binders immobilized and after curing a Immobilisat high strength and low elution of trapped pollutants under real elution conditions is deposited. Apparatus for purifying acidic, iron- and sulphate-containing mining waters, by means of earth or concrete basins, inclined clarifiers or round thickeners with craters, in which the inflow of the mining waters to be purified from a distribution box ( 2 ) above a multi-chamber reaction pool ( 9 ) in free fall via one or more inlet nozzles ( 3 ) with different lengths, due to different integration lengths (L _e ) of the inlet nozzles ( 3 ) in the distribution box ( 2 ), wherein the diameter of the inlet nozzle ( 3 ) in the ratio of inlet diameter (D ₃ ) of the inlet nozzle: outlet diameter (D ₄ ) of the inlet nozzle is 1.5 to 2.5: 1 and at the outlet of each inlet nozzle (D ₃ ) 3 ) an atomizer ( 19 ) with air inlet openings and / or inside a nebulizer grid is mounted, in a first chamber ( 10 ) of the multi-chamber reaction pool ( 9 ) according to the water jet pump principle, the multi-chamber reaction tank ( 9 ) from at least two chambers to be ventilated ( 10 ), the volume of the respective chamber ( 10 ) is determined by the required residence time of the raw water to be purified, and overflows ( 11 ) between the chambers ( 10 ) are arranged offset in the intermediate walls, and in which the cross-sectional areas of an inlet pipe ( 12 ) of a high-performance thickener ( 14 ), a guide tube ( 13 ) of the high-performance thickener ( 14 ), which has a constriction shortly before exiting, and the high-performance thickener ( 14 ) in the ratio cross-sectional area of the inlet tube (A ₀ ): cross-sectional area of the guide tube (A ₁ ): cross-sectional area of the guide tube at the constriction (A ₂ ): cross-sectional area of the guide tube at the outlet (A ₃ ): cross-sectional area of the high-performance thickener (A ₄ ) is 0, 05 to 0.2: 1: 0.3 to 0.7: 0.5 to 0.9: 5 to 9, wherein an upper sludge level ( 18 ) between at least 1.5 m above the outlet edge of the guide tube ( 13 ) up to 0.5 m below the overflow edge of a clear water outlet ( 17 ) and the absolute size of the cross-sectional area of the high-performance thickener ( 14 ) is adapted to the nominal flow rate of the plant. Apparatus according to claim 4, characterized in that a constant level height of the mining waters to be cleaned in the distribution box ( 2 ) by the number of inlet nozzles ( 3 ), the dimensioning of the inlet diameter (D ₃ ) of the inlet nozzle ( 3 ) and the outlet diameter (D ₄ ) of the inlet nozzle ( 3 ) such as the different bond lengths (L _e ) of the inlet nozzles ( 3 ) is regulated.