WO2023183965A1 - Treatment methods, apparatus and additive - Google Patents

Treatment methods, apparatus and additive Download PDF

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Publication number
WO2023183965A1
WO2023183965A1 PCT/AU2023/050216 AU2023050216W WO2023183965A1 WO 2023183965 A1 WO2023183965 A1 WO 2023183965A1 AU 2023050216 W AU2023050216 W AU 2023050216W WO 2023183965 A1 WO2023183965 A1 WO 2023183965A1
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WO
WIPO (PCT)
Prior art keywords
water
additive
pond
treatment according
water treatment
Prior art date
Application number
PCT/AU2023/050216
Other languages
French (fr)
Inventor
Kevin Joseph Murphy
Michael Shaun Higgins
Original Assignee
Eagle Innovations Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2022900800A external-priority patent/AU2022900800A0/en
Application filed by Eagle Innovations Pty Ltd filed Critical Eagle Innovations Pty Ltd
Publication of WO2023183965A1 publication Critical patent/WO2023183965A1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/30—Injector mixers
    • B01F25/31—Injector mixers in conduits or tubes through which the main component flows
    • B01F25/312—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof
    • B01F25/3124—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof characterised by the place of introduction of the main flow
    • B01F25/31241—Injector mixers in conduits or tubes through which the main component flows with Venturi elements; Details thereof characterised by the place of introduction of the main flow the main flow being injected in the circumferential area of the venturi, creating an aspiration in the central part of the conduit
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
    • B01F25/60—Pump mixers, i.e. mixing within a pump
    • B01F25/64—Pump mixers, i.e. mixing within a pump of the centrifugal-pump type, i.e. turbo-mixers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/14—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means with multiple outlet openings; with strainers in or outside the outlet opening
    • B05B1/20—Arrangements of several outlets along elongated bodies, e.g. perforated pipes or troughs, e.g. spray booms; Outlet elements therefor
    • B05B1/205—Arrangements of several outlets along elongated bodies, e.g. perforated pipes or troughs, e.g. spray booms; Outlet elements therefor characterised by the longitudinal shape of the elongated body
    • B05B1/207—Arrangements of several outlets along elongated bodies, e.g. perforated pipes or troughs, e.g. spray booms; Outlet elements therefor characterised by the longitudinal shape of the elongated body the elongated body being a closed loop
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B1/00—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means
    • B05B1/34—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to influence the nature of flow of the liquid or other fluent material, e.g. to produce swirl
    • B05B1/3402—Nozzles, spray heads or other outlets, with or without auxiliary devices such as valves, heating means designed to influence the nature of flow of the liquid or other fluent material, e.g. to produce swirl to avoid or to reduce turbulencies, e.g. comprising fluid flow straightening means
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B7/00—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas
    • B05B7/24—Spraying apparatus for discharge of liquids or other fluent materials from two or more sources, e.g. of liquid and air, of powder and gas with means, e.g. a container, for supplying liquid or other fluent material to a discharge device
    • B05B7/2402—Apparatus to be carried on or by a person, e.g. by hand; Apparatus comprising containers fixed to the discharge device
    • B05B7/244—Apparatus to be carried on or by a person, e.g. by hand; Apparatus comprising containers fixed to the discharge device using carrying liquid for feeding, e.g. by suction, pressure or dissolution, a carried liquid from the container to the nozzle
    • B05B7/2443—Apparatus to be carried on or by a person, e.g. by hand; Apparatus comprising containers fixed to the discharge device using carrying liquid for feeding, e.g. by suction, pressure or dissolution, a carried liquid from the container to the nozzle the carried liquid and the main stream of carrying liquid being brought together downstream of the container before discharge
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/101—Sulfur compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2209/00—Controlling or monitoring parameters in water treatment
    • C02F2209/06—Controlling or monitoring parameters in water treatment pH

Definitions

  • the present invention relates to a treatment method, and in particular to a treatment method for “Acid Mine Water.
  • open cut mining is a frequently used method to remove the valuable ore.
  • open cut mining has a problem that water accumulates in the open mine pits. The water can be from run off and surface water, but also includes water from seepage from aquifers disturbed during the pit excavation. As the pit is dug sulphide bearing rocks are exposed and when exposed to water and oxygen produce sulphuric acid. These naturally occurring aquifers cross many layers of rock, including natural iron deposits, sulphates, pyrites and other minerals. The aquifer water permeates the strata, and the minerals become soluble and enter the water.
  • the aquifer water therefore contains a high concentration of suspended minerals, which when it seeps into the mine pit is exposed to oxygen. As the minerals oxidise, various compounds are formed, which remain suspended in the pit. Some mine water pits also have gas outlets sparging through the water which acts on the dissolved minerals.
  • the gas can be methane and can also contain sulphur dioxide, where the gas is permeated from subsurface deposits. Sulphur dioxide is highly soluble and so as it contacts the water it forms sulphuric acid, causing the pit water to become acidic, and known as “Acid Mine Water”.
  • Acid Mine Water so called, is a dangerous environmental and economic problem for the mine.
  • the low pH of the acid water is lethal to aquatic life such as tortoises, frogs and fish, so its presence creates a dangerous toxic pool.
  • the danger extends to the surrounding area and wildlife that may visit the pool.
  • the acidic water is too acid to be used for other purposes. While there are purposes where water that is not potable can be used, it is highly undesirable to use acidic water anywhere at the mine as it will corrode equipment, vehciles, stain vehicle paintwork and kill vegetation.
  • Acid Mine Water In addition to the low pH of the Acid Mine Water, there are high levels of dissolved minerals such as iron, calcium, manganese, sulphates and others. These dissolved minerals in the water can lead to staining if used to wash down surfaces or machines, and can damage decorative surfaces. Further the acidity and high mineral content of the Acid Mine Water means that the water cannot be safely used on vegetation as it is likely to burn or cause damage.
  • the inventors have developed a new method of treatment and additive that can be used to treat Acid Mine Water to address both the acidity and the high levels of dissolved minerals so the water can then be used.
  • the inventors use a measured additive to increase the alkalinity of the water to address the acid, but also the action of the additive causes the minerals to react causing oxidation and ion reduction which causes the precipitation of the particles suspended in the water, the Redox principle..
  • the clear water with a neutral pH is then suitable for use at the mine site without damaging infrastructure. While not potable water, the water is suitable for most other general purpose tasks around the mine site.
  • the water By treating the acidity, the water can be used for washing, irrigation and dust suppression without the risk of corrosion and damage to surfaces, or to equipment within the mine such as pumps, piping or evaporators, for example.
  • the mineral content has also be addressed to remove potentially staining agents from the water the water can be used on surfaces without the staining.
  • the ability through use of the method and additive of treating Acid Mine Water is a significant advance over existing methods and the prior ar. In testing, use of the invention clarifies and returns the water pH to neutral, such that aquatic life can again live in the water.
  • the subject invention has been carefully considered, and surprisingly finds a clever new method of treating Acid Mine Water to address both the acidic pH and the high levels of soluble minerals so the processed water can be used.
  • the invention is a significant invention that will be of great economic and environmental benefit to the mine owners. There is also a further potential benefit of reclaiming valuable minerals and even rare earth metals from the precipitated sludge.
  • the invention is one that is described for the very useful application for treatment of Acid Mine Water to neutralise the pH to enable use of the water and to remove through settling out of the particulates.
  • this very useful invention has numerous applications, and can be used not just for acid water but can also be used to alter the pH of the water to a desired pH in other situations, and to change other compounds, substances, contaminants and properties of non-acidic water to precipitate solids and particulates from these waters.
  • the present invention provides in a method of treatment for Acid Mine Water, the method including the steps of: a) assessing the water to be treated; b) determining additive to be added to the assessed water; c) introducing the additive to the water to a settlement pond; wherein the action of the additive on the contaminants in the water reacts causing them to settle out of the water and alters the acidity of the water and removes particulates.
  • the acid water is neutralised by the additive.
  • the additive is added to the water before introduction to the settlement pond so that the water and additive are mixed but there is no undue disturbance to the settlement pond.
  • the present invention provides in a method of treatment for Acid Mine Water, the method including the steps of: a) assessing the water to be treated; b) determining additive to be added to the assessed water; c) introducing the additive to the water before introduction to a settlement pond whereby the additive is mixed with the water and the settlement not significantly disturbed by the introduction of the additive; wherein the action of the additive on the contaminants in the water reacts causing them to settle out of the water in the settlement pond, and substantially neutralises the acid from the water and removes particulates.
  • the present invention provides a method of treatment for Acid Mine Water, the method including the steps of: a)assessing water for treatment including testing the water for pH and composition such as dissolved chemicals, contaminants and particulates; b) determining the approximate volume of water to be treated or flow rate; c) determining the additive suitable to treat the determined pH, volume of water and or flow rate; and d) adding the additive to the water, wherein the action of the additive on the contaminants in the water reacts causing them to settle out of the water and substantially neutralises the acid from the water and removes particulates.
  • the adding of the additive to the water occurs before the water is introduced to a settlement pond.
  • the additive is thoroughly mixed with water to be treated through a pump and or injection system before the water passes to a settlement pond.
  • the introduction of the treated water to the settlement pond is such that the settlement pond is not unduly disturbed.
  • the present invention provides in a further variant a method of treatment for Acid Mine Water, the method including the steps of: a) determining the approximate volume of water to be treated; b) measuring additive to a suitable weight suitable to treat the determined volume of water; c) pumping water while adding the additive to the water to a settlement pond; wherein the action of the additive on the contaminants in the water reacts causing them to group together and over time fall under gravity and substantially neutralises the acid from the water and removes particulates and the pumping of the water before introduction to the settlement pond enables mixed addition of additive and water substantially without disturbing the settlement pond.
  • the water treated is Acid Mine Water in a pit, as is a very useful application of the invention.
  • the invention may be used to treat any water.
  • the water may be non-acidic in some uses of the invention.
  • the invention be used where the pH needs adjusting to any suitable adjustment.
  • the invention may be used where the pH does not need adjustment.
  • the invention may be used for the settling out feature only, in some forms.
  • the assessing is any suitable assessing of the water for treatment.
  • the assessing of the water includes determining the volume of water to be treated.
  • the determining of the volume of water may be a volume of a pit pond.
  • the volume may be the flow rate.
  • the additive is added to the water flowing between the pit pond and the settlement pond.
  • the flow rate from a pit pond to a settlement pond may be included.
  • the assessing of the water may include testing of the water.
  • the testing of the water may include pH testing.
  • the testing may be laboratory testing.
  • the testing may include for any chosen from the following group: minerals; salts; organic materials; contaminants; heavy metals; bacteria; rare earth metals; volatile organic compounds; any chemicals; or any solids.
  • the assessing of the water includes determining the volume or flow rate, pH and testing for contaminants.
  • the determining of the water is calculating the approximate volume of water in the pit.
  • the step may be omitted and the additive added until the water is processed in a different form of the invention.
  • the water volume is determined so that the additive can be applied to give a 3.5% solution result.
  • the additive is sodium hydroxide.
  • the additive may be any on eor more of the 34 known hydroxides.
  • the additive is sodium hydroxide applied in 10% percentage solution. A 2.5% to 12% solution may be used.
  • the additive is sodium hydroxide in 10% solution applied at 3.5% of the water volume.
  • the additive is potassium hydroxide.
  • the additive may in other forms of the invention be chosen from the group: sodium hydroxide; potassium hydroxide; calcium hydroxide; other alkaline compounds; and combinations thereof.
  • the additive is a suitable additive to cause an alkalising effect on the acidic water.
  • the additive is suitable to cause a reaction in the particulates so that they group or clump together and fall to the bottom.
  • Other forms means of clarifying the water may be used as well as the settling action.
  • Any suitable use of a hydroxide to alter the pH may be used.
  • the hydroxide used to reduce acidity or otherwise change the pH also acts to cause contaminants to settle out of the water.
  • the invention is used with a settlement pond in fluid communication with the pit water. Most preferably, the water is pumped from the pit to a settlement pond. Most preferably the additive is added through the pump. Most preferably, the addition of the additive is with use of an impeller to thoroughly mix the additive into the water.
  • the additive is added with a mixing step to thoroughly mix the additive into the water.
  • the mixing occurs without disturbance of a settlement pond.
  • a settlement pond is included and water is pumped from the pit to the settlement pond.
  • introduction of the additive is between the pit and the settlement pond.
  • the introduction of the additive is related to the pumping of the water from the pump to the settlement pond.
  • the water and additive mix is introduced to the settlement pond in a gentle manner, whereby the water is not unduly disturbed.
  • water is introduced to a settlement pond through a spray.
  • water is sprayed to a settlement pond to minimise disturbance to the water.
  • water is pumped from the pit to the settlement pond, the additive is introduced with mixing before being sprayed on to the settlement pond.
  • an additional step of settling the water is included.
  • these settled particles can be removed from the water.
  • the method substantially neutralises the water.
  • the resultant water can be removed from the settlement pond.
  • the water may be pumped from the settlement pond to a holding tank.
  • the resultant water is substantially clear water usable for general purposes.
  • the resultant water is suitable for aquatic life and wildlife to contact.
  • the resultant water has a low risk or impact to the environment.
  • the resultant water has reduced mineral content. The reduced mineral content will therefore not impact through staining or otherwise when being used for washing or watering for example.
  • the resultant water is substantially neutral.
  • the resultant water is significantly less acidic than at the start.
  • the water is brough towards substantially neutral.
  • the water may be taken from around pH 2.1 to substantially 7.5 pH .
  • the resultant water is water suitable for other uses. The water may be deemed clear or pure water.
  • use of the invention substantially removes soluble iron from the water.
  • use of the invention reduces calcium, nickel and other suspended solid levels in the water.
  • use of the method enables high volume processing of acidic water to usable water. Millions of litres may be processed each day, through use of this invention.
  • the invention also provides an additive for use to treat acidic water, the additive being sodium hydroxide.
  • the sodium hydroxide is used in substantially 10 % solution.
  • the 10 % solution will be dosed at a 3.5% of pit water volume. The dosing may be in the range of 2.5% to 12 %.
  • the present invention provides, in a variant, a method of treatment of contaminated water, the method including the steps of: a) determining the volume of water to be treated; b) measuring additive, to a suitable weight suitable to treat the determined volume of water; c) adding the additive to the water; d) settling the water and additive, whereby the action of the additive on the contaminants in the water reacts causing them to settle out and over time fall under gravity; and e) removal of treated water for use elsewhere, wherein the use of the additive substantially neutralises the acid from the water and removes particulates.
  • the present invention provides, in a further variant, a method of treatment of contaminated water, the method including the steps of: a) determining the volume of water to be treated; b) measuring additive, sodium hydroxide, to a suitable weight suitable to treat the determined volume of water; c) adding the sodium hydroxide to the water; d) settling the water and sodium hydroxide, whereby the action of the additive on the contaminants in the water reacts causing them to group together and over time fall under gravity; and e) removal of treated water for use elsewhere, wherein the use of the additive substantially neutralises the acid from the water and removes particulates so the water is suitable for use for other purposes.
  • the contaminants in the water may be anything in the water that it may be useful to settle out through use of the invention.
  • the contaminants may actually be beneficial minerals or particulates that happen to be in the water that it is useful to obtain from the water.
  • the invention may be used to obtain anything suitable from the water, which may be for further use. While generally the contaminants will be just that minerals and particulates acquired during the mine process there could be a wide range of dissolved or suspended things in the water, that it may be desired to obtain and potentially remove.
  • Any one or more of the steps of the method may be omitted. Any one or more of the steps of the method may be reordered in some forms of the invention.
  • the testing test may be omitted and the additive may be used as suitable from previous experience at the site.
  • the volume of water determining step may be omitted, where appropriate.
  • the invention is directed to use for acid mine water but can be used on any water. Should the pH not be acidic, the process will still work to clump and remove the particulates from the water but in this case the pH of the water may become alkali. If this is the case the pH can be corrected to neutral thereafter in the usual fashion before use. Or it is possible that the water to be used is desired to have another pH other than neutral, and in this case the pH can be adjusted to the desired pH. It is anticipated that adaptation and variation may be made to this significant invention to suit a particular use.
  • the additive may be use of a single chemical additive, or may be the use of any number of suitable additives as may be required by the particular application.
  • the invention also provides apparatus for use for treatment of Acid Mine Water including a pump and a settlement pond, wherein water is pumped to a settlement pond and additive introduced.
  • the invention also provides apparatus for use for treatment of water in a pond, the apparatus including: a pump in fluid communication with the pond; a settling pond, able to receive water; and a spray arrangement for spraying water pumped from the pond to the settling pond, wherein additive may be introduced to the water during pumping and the additive acts to reduce the acidity and act on the minerals contained in the water.
  • the invention also provides, in a variant, apparatus for use for treatment of water in a pond, the apparatus including: a pump in fluid communication with the pond through a conduit; an impeller for mixing water able to act on the water in the conduit; a settling pond, able to receive water; and a spray arrangement for spraying water pumped from the pond to the settling pond from the conduit, wherein additive may be introduced to the water during pumping and the additive acts to reduce the acidity and act on the minerals contained in the water, and clear water may be separated from the settlement ponds.
  • the additive is sodium hydroxide. Any suitable additive may be used.
  • the additive may be any alkalising additive.
  • the additive is sodium hydroxide in a 10 percent solution. Preferably the solution is dosed at 3.5 percent of the pit water volume. Other concentrations and dosing may be used and adapted accordingly.
  • the mixing of the additive is introduced with action to encourage the reaction of the additive and the minerals in the water.
  • an impeller is used to vigorously mix the additive into the pit water.
  • the impeller may be any suitable means to mix the additive and water.
  • the mixing occurs outside of the pit and any settlement pond.
  • the mixing occurs during the pumping step.
  • the mixing may take any suitable form.
  • the pump includes a pipe and the mixing occurs in the pipe.
  • the mixed water and additive is introduced to the settlement pond.
  • the introducing is in any suitable manner.
  • the introducing of the water to the settlement pond is gentle, so as not to disturb the already settling water.
  • a spray arrangement is included.
  • a spray arrangement is included and the mixed water is sprayed onto the settlement pond so as not to disturb the water unduly.
  • a holding tank is included.
  • treated water may be removed for use.
  • the water may be removed for further treatment or to a holding tank.
  • the treatment enables rapid treatment of the water and access to clear water within a few hours.
  • clear water can be produced through use of the apparatus and method rapidly.
  • the quantity of additive used is determined by the pH of the water and calculated water volume or flow rate. Other methods of additional reduction of acidification may be used with the invention.
  • the methods of injecting and or pumping the additive into the water can take any suitable form. Additional method of injecting or pumping the additive into the water can be used, to thoroughly mix the water.
  • the settled material may contain valuable precipitate.
  • the settled material can be further assessed for valuable and recoverable resources.
  • valuable resources may be assessed and considered for recovery.
  • other methods of recovery may be introduced at this point to obtain the resource.
  • the apparatus may include any of the features described with respect to the method.
  • the method is for use to treat acid mine water to enable the neutralised and decontaminated water to be used for other purposes, a useful industrial application. Obtained contaminants from the water may be separated for further use or sale.
  • Figure 1 is a perspective view from the side of a settling pond of the invention according to a preferred embodiment of the invention
  • Figure 2 is a schematic of a system arrangement of the preferred embodiment of the invention.
  • Figure 3 is a cross-sectional view from the front of the impeller of the preferred embodiment, the rest of the apparatus being omitted;
  • Figure 4 is a cross-sectional view from the side of the impeller of Figure 3;
  • Figure 5 is a system layout diagram.
  • apparatus 1 is the general reference to all the apparatus used to achieve the method, and the example of the inventive apparatus.
  • Apparatus 1 will be installed at a mine site or similar location where use of the invention is most useful with inflow ring main labelled generally 5.
  • Each mine site will be slightly different as the pit pond, settlement pond and connecting pumps and inlets and outlets will be shaped and sized to suit the particular site.
  • the apparatus will be installed to suit the particular arrangement as would be understood by the person skilled in the art, while maintaining the inventive principles. This very useful invention will be able to be installed in a wide range of applications due to this adaptability.
  • Pond discharge pump 16 can be used to remove liquid from the upper part of pond 12, while sludge 18 forms at the bottom and can be removed direct from the sludge area of pond 12 by use of sludge pump 20.
  • Interface 22 is used between sludge suction pipe 24 close to the bottom of settling pond 12, to minimise disturbance as sludge pump 20 is operated to remove sludge 18.
  • Floats 26 are included on the surface of settling pond 12. Data is collected through use of sensors and these can be used to detect any suitable data. As shown pH is measured throughout the system through use of pH sensors 28. Interface sensors 30 are included to similarly sense conditions at the interface. Chemical dosing system 32 can be seen in particular in Figure 2 as will be used to adjust the pH is response to the system data as described further below. Adjustments can then be made via a control unit (not shown) to adjust the pH to be suitable for use, before the water is pumped out through pump discharge pump 16. The water has been treated to make is usable in other applications around the mine site and so can be used directly or pumped to tank for use later, or moved to elsewhere for use. The control unit has power and through standard actuation can be used to control valves labelled generally 34. The pumps and valves of the system are controlled in the usual manner to open and close and allow or prevent flow of the liquid, as would be readily understood.
  • impeller 36 is shown with suction/suction eye 38 and vanes 40.
  • Volute casing 42 contains discharge 44 introduced as driving fluid 46, through body 48, with diffuser 50 , nozzle 52, screw 54 and Gasket/O-ring 56.
  • Other forms of impeller could be used instead.
  • the additive used is sodium hydroxide to treat the Acid Mine Water.
  • Other additives could be used instead, including potassium hydroxide, and calcium hydroxide, other alkaline compounds, and including combinations thereof.
  • the acidic water is not usable in mine pit 10, due to the low pH and dissolved minerals. Therefore, through use of the additive, a strong alkaline solution is created that acts at a concentration capable of causing rapid oxidisation and reaction with the suspended solids. When applied correctly use of the additive acts to react in the solution to cause a precipitate/sludge 18 to form in the water. The created precipitate settles quickly to the bottom of the water of settling pond 12 as a brown sludge, so as to be separated from the clear water.
  • the method of treatment can be used on Acid Mine Water in pit 10 of the mine, where an earthen pond of at least 3 metres is formed.
  • the surface area of the pond will dictate the volume of water that can be treated in a day.
  • Water can be pumped from the pit pond 10 to settling pond 12 and as this occurs the pit water is treated with the solution by introducing the sodium hydroxide solution at 10 % to dose 3.5% of the pit water volume.
  • impeller 36 thoroughly mixes the solution of the additive into the pit water as it passes through the pump.
  • the mixed water is then delivered to the settling pond, where the coagulation occurs rapidly, as does the settling out of the precipitates.
  • the mixing delivery at the pump is useful as it means that the mixing occurs separate from the settling ponds and so the settling ponds are not disturbed by the vigorous mixing.
  • a ring main of PVC pipe is made to surround the perimeter of the settling pond.
  • the pit water is directed into the ring main which has numerous holes of 12 mm diameter facing the surface area of the pond thus causing numerous small jets of water directed into the air above the settling pond.
  • the clear water on the top of the pond can be removed by using a pump with a floating suction line to deliver the water to its destination around the site, the bottom layer of coagulated minerals and sulphates can also be removed by a pump with a bottom of the pond suction line.
  • the resultant precipitate is suitable to irrigate over areas to be reclaimed by mine site revegetation, and is an ideal mineral supplement for growing plants such a native grasses, eucalyptus species casuarinas and all iron loving plants. There is a possible consideration that citrus being iron loving plants would flourish in areas irrigated with this residue.
  • the additive will cause a Redox reaction in non acidic water also. Precipitate will settle out but pH will become alkali.
  • Processing the mine water with the additive will be worked out with injected with the additive at varying to a point where the mines is achieved.
  • the additive can be any of the 34 known mixed with neutral water giving a pH around pH 13.5.
  • T ermined with the mine water to where the are achieved. of the m ix to the acid water is between 2.5% to 12% .
  • the additive is potassium hydroxide.
  • the additive may in other forms of the invention be chosen from the group: sodium hydroxide; potassium hydroxide; lithium hydroxide; other alkaline compounds; and combinations thereof.
  • the of water to be treated by the additive is limited by the size of the d the chemical and the to transfer the water from the or
  • the pit water once treated, clean and neutral, can be further utilised to make the chemical water mix on site to save on transport cost.
  • the water can be used on or even Potable water in more remote areas.
  • the labels for the include:
  • Interface sensor to indicate max level of level.
  • Chemical is injected continually into the suction hose end in the mine pit water.
  • the intention with the chemical injection is to spray the chemical at a reasonably high pressure so as to start the redox reaction, which reduces the Ph and initiates the settling out of the suspended solids in the mine water.
  • the chemical is supplied from a storage tank of sufficient size to run the operation for a pre determined time.
  • the adjustment of the supply of chemical is achieved by a controller at the Ph sensor downstream of the transfer Pump where the Ph should be at its required level.
  • the controller takes the Ph reading and adjusts the supply of chemical from the dosing valve after the dosing pump. This is occuring continually during the process
  • the mix then enters the discharge ringmain which sits a metre above the Settling pond.
  • the water mix discharges through many small bore holes aimed down toward the pond designed to form a spray which will prevent disturbance in the setting pond surface which will aid the settling out of the sludge.
  • the Settling Pond or Ponds are of sufficient size to meet the Mines water demand as required.
  • the average level of sludge is in the range of around 15% of the sample or in this case the settling pond.
  • This pipe has multiple holes in the top half by which the sludge can be drawn from the full length of the pit without causing turbulence in the water ensuring a minimal amount of the clear water is taken with the sludge.
  • the Sludge Pump will remove the sludge back to the pit or to another area if more treatment is deemed necessaryry.
  • One option could be if the sludge settles out quickly, it could be pumped out of the settling pond prior to settling pond being used for its daily services.
  • the Floating suction is designed to take the clean water from the Settling pond and to ensure the sludge isnt picked up during supply of clean water to mine services.
  • the system is completely automated with remote alerting of Ph, system operation, system faults, chemical storage status, precipitate level
  • the method of treatment can be used on Acid Mine Water in a pit of the mine, where a settling pond of at least 4 metres depth is formed.
  • the surface area of the pond will dictate the volume of water that can be treated in a day.
  • Acid water can be pumped from the pit pond to the settling pond and as this occurs the pit water is treated with the solution by introducing the hydroxide solution at between 2.5% and 12% to dose the water The chemical is injected at a point where the suction hose starts in the pit. the time it reaches the suction side of the pump, its pH will be close to or at
  • the mixed water is then delivered to the settling pond, where the clarification occurs , as does the settling out of the precipitates.
  • the water is divided into two separate layers, the top being crystal clear and the bottom being the sludge of the precipitate.
  • is sludge as seen from all our testing is generally 15% of

Abstract

The invention relates to a method of treatment for Acid Mine Water including the steps of assessing the water to be treated, determining additive to be added to the assessed water and introducing the additive to the water before introduction to a settlement pond whereby the additive is mixed with the water and the settlement not significantly disturbed by the introduction of the additive. In this way the action of the additive on the contaminants in the water reacts causing them to settle out of the water in the settlement pond, and substantially neutralises the acid from the water and removes particulates. The invention also relates to a corresponding apparatus. The invention also relates to variants thereon.

Description

TREATMENT METHODS, APPARATUS AND ADDITIVE
The present invention relates to a treatment method, and in particular to a treatment method for “Acid Mine Water.
The application is subject of Australian provisional patent application 2022900800 and 2022902641 priority date 30 March 2022, the contents of both of which is incorporated by reference.
BACKGROUND OF THE INVENTION
Mining is an invaluable part of the world economy, and open cut mining is a frequently used method to remove the valuable ore. However, open cut mining has a problem that water accumulates in the open mine pits. The water can be from run off and surface water, but also includes water from seepage from aquifers disturbed during the pit excavation. As the pit is dug sulphide bearing rocks are exposed and when exposed to water and oxygen produce sulphuric acid. These naturally occurring aquifers cross many layers of rock, including natural iron deposits, sulphates, pyrites and other minerals. The aquifer water permeates the strata, and the minerals become soluble and enter the water. The aquifer water, therefore contains a high concentration of suspended minerals, which when it seeps into the mine pit is exposed to oxygen. As the minerals oxidise, various compounds are formed, which remain suspended in the pit. Some mine water pits also have gas outlets sparging through the water which acts on the dissolved minerals. The gas can be methane and can also contain sulphur dioxide, where the gas is permeated from subsurface deposits. Sulphur dioxide is highly soluble and so as it contacts the water it forms sulphuric acid, causing the pit water to become acidic, and known as “Acid Mine Water”.
Acid Mine Water, so called, is a dangerous environmental and economic problem for the mine. The low pH of the acid water is lethal to aquatic life such as tortoises, frogs and fish, so its presence creates a dangerous toxic pool. The danger extends to the surrounding area and wildlife that may visit the pool. Also the acidic water is too acid to be used for other purposes. While there are purposes where water that is not potable can be used, it is highly undesirable to use acidic water anywhere at the mine as it will corrode equipment, vehciles, stain vehicle paintwork and kill vegetation.
In addition to the low pH of the Acid Mine Water, there are high levels of dissolved minerals such as iron, calcium, manganese, sulphates and others. These dissolved minerals in the water can lead to staining if used to wash down surfaces or machines, and can damage decorative surfaces. Further the acidity and high mineral content of the Acid Mine Water means that the water cannot be safely used on vegetation as it is likely to burn or cause damage.
Water is a valuable resource, and there is a high demand for water in industry and at mine sites. If the Acid Mine Water were usable, this would be of an enormous benefit to the mine as the water can be used for washing and watering, dust suppression, and general purpose water, for example. In order that the water can be used the acidic and high mineral content needs to be addressed, and this is a serious problem.
The problem is known around the world, everywhere there are mines, and attempts have been made to solve the problem so the water may become usable. Previously special clays including bentonite has been used to neutralise the acidity and try to bring the pH back towards neutral. The use of the clay is expensive, and produces a significant volume of bentonite sludge as a result of the neutralising the pH of the water. Therefore, the use of bentonite clays is not a suitable solution to the problem as it creates further problems, as the sludge must be addressed. Lime has also been used but it is difficult to mix into the water, further heavy metal can be unintentionally added into the water in this process.
Another attempt to solve the problem of making Acid Mine Water useable was use of a reverse osmosis separation. The process may separate water from particulates but does nothing to address the acidity of the water. If the water is still a low pH and acidity it still cannot be used. Further, the inclusion of the suspended soluble iron in the water rapidly blocks the membranes used for the separation, making the process problematic. The result is that the iron residues cannot be flushed from the system and so the process will need to be stopped.
Therefore, there has long been a want for an economic, simple and environmentally friendly means to treat Acid Mine Water, so it can be made useable for other purposes, that does not suffer the significant problems of the prior art.
The inventors have developed a new method of treatment and additive that can be used to treat Acid Mine Water to address both the acidity and the high levels of dissolved minerals so the water can then be used. The inventors use a measured additive to increase the alkalinity of the water to address the acid, but also the action of the additive causes the minerals to react causing oxidation and ion reduction which causes the precipitation of the particles suspended in the water, the Redox principle.. The clear water with a neutral pH is then suitable for use at the mine site without damaging infrastructure. While not potable water, the water is suitable for most other general purpose tasks around the mine site.
By treating the acidity, the water can be used for washing, irrigation and dust suppression without the risk of corrosion and damage to surfaces, or to equipment within the mine such as pumps, piping or evaporators, for example. As the mineral content has also be addressed to remove potentially staining agents from the water the water can be used on surfaces without the staining. The ability through use of the method and additive of treating Acid Mine Water is a significant advance over existing methods and the prior ar. In testing, use of the invention clarifies and returns the water pH to neutral, such that aquatic life can again live in the water.
The subject invention has been carefully considered, and surprisingly finds a clever new method of treating Acid Mine Water to address both the acidic pH and the high levels of soluble minerals so the processed water can be used. The invention is a significant invention that will be of great economic and environmental benefit to the mine owners. There is also a further potential benefit of reclaiming valuable minerals and even rare earth metals from the precipitated sludge.
The invention is one that is described for the very useful application for treatment of Acid Mine Water to neutralise the pH to enable use of the water and to remove through settling out of the particulates. However, this very useful invention has numerous applications, and can be used not just for acid water but can also be used to alter the pH of the water to a desired pH in other situations, and to change other compounds, substances, contaminants and properties of non-acidic water to precipitate solids and particulates from these waters.
The following describes a non-limiting example of the invention being used with reference to treatment of Acid Mine Water. It is not intended that the invention be limited in its scope to treatment of Acid Mine Water, other than as defined in the claims. However, the use of the invention to treat Acid Mine Water is a particularly useful application of the invention. The invention may, however, be used to treat any water that may benefit from the treatment. It is envisaged that other water may benefit from a similar inventive use of the method and additive. For clarity, any prior art referred to herein, does not constitute an admission that the prior art forms part of the common general knowledge, in Australia or elsewhere.
It is an object of the present invention to provide a method of treatment of water that at least ameliorates one or more of the aforementioned problems of the prior art. It is a further and separate object of the present invention to provide an additive that at least ameliorates one or more of the aforementioned problems of the prior art.
DISCLOSURE OF THE INVENTION
Accordingly, the present invention provides in a method of treatment for Acid Mine Water, the method including the steps of: a) assessing the water to be treated; b) determining additive to be added to the assessed water; c) introducing the additive to the water to a settlement pond; wherein the action of the additive on the contaminants in the water reacts causing them to settle out of the water and alters the acidity of the water and removes particulates.
Preferably, the acid water is neutralised by the additive. Preferably, the additive is added to the water before introduction to the settlement pond so that the water and additive are mixed but there is no undue disturbance to the settlement pond.
Accordingly, the present invention provides in a method of treatment for Acid Mine Water, the method including the steps of: a) assessing the water to be treated; b) determining additive to be added to the assessed water; c) introducing the additive to the water before introduction to a settlement pond whereby the additive is mixed with the water and the settlement not significantly disturbed by the introduction of the additive; wherein the action of the additive on the contaminants in the water reacts causing them to settle out of the water in the settlement pond, and substantially neutralises the acid from the water and removes particulates.
Accordingly, the present invention provides a method of treatment for Acid Mine Water, the method including the steps of: a)assessing water for treatment including testing the water for pH and composition such as dissolved chemicals, contaminants and particulates; b) determining the approximate volume of water to be treated or flow rate; c) determining the additive suitable to treat the determined pH, volume of water and or flow rate; and d) adding the additive to the water, wherein the action of the additive on the contaminants in the water reacts causing them to settle out of the water and substantially neutralises the acid from the water and removes particulates.
Preferably, the adding of the additive to the water occurs before the water is introduced to a settlement pond. Preferably, the additive is thoroughly mixed with water to be treated through a pump and or injection system before the water passes to a settlement pond. Preferably, the introduction of the treated water to the settlement pond is such that the settlement pond is not unduly disturbed.
Accordingly, the present invention provides in a further variant a method of treatment for Acid Mine Water, the method including the steps of: a) determining the approximate volume of water to be treated; b) measuring additive to a suitable weight suitable to treat the determined volume of water; c) pumping water while adding the additive to the water to a settlement pond; wherein the action of the additive on the contaminants in the water reacts causing them to group together and over time fall under gravity and substantially neutralises the acid from the water and removes particulates and the pumping of the water before introduction to the settlement pond enables mixed addition of additive and water substantially without disturbing the settlement pond.
Preferably, the water treated is Acid Mine Water in a pit, as is a very useful application of the invention. However, other water may be treated similarly. The invention may be used to treat any water. The water may be non-acidic in some uses of the invention. The invention be used where the pH needs adjusting to any suitable adjustment. The invention may be used where the pH does not need adjustment. The invention may be used for the settling out feature only, in some forms. Preferably, the assessing is any suitable assessing of the water for treatment. Preferably, the assessing of the water includes determining the volume of water to be treated. The determining of the volume of water may be a volume of a pit pond. The volume may be the flow rate. Preferably, the additive is added to the water flowing between the pit pond and the settlement pond. The flow rate from a pit pond to a settlement pond may be included. The assessing of the water may include testing of the water. The testing of the water may include pH testing. The testing may be laboratory testing. The testing may include for any chosen from the following group: minerals; salts; organic materials; contaminants; heavy metals; bacteria; rare earth metals; volatile organic compounds; any chemicals; or any solids. Most preferably, the assessing of the water includes determining the volume or flow rate, pH and testing for contaminants. Preferably, the determining of the water is calculating the approximate volume of water in the pit. The step may be omitted and the additive added until the water is processed in a different form of the invention. Preferably, the water volume is determined so that the additive can be applied to give a 3.5% solution result.
Preferably, the additive is sodium hydroxide. The additive may be any on eor more of the 34 known hydroxides. Preferably, the additive is sodium hydroxide applied in 10% percentage solution. A 2.5% to 12% solution may be used. Preferably, the additive is sodium hydroxide in 10% solution applied at 3.5% of the water volume. Optionally the additive is potassium hydroxide. The additive may in other forms of the invention be chosen from the group: sodium hydroxide; potassium hydroxide; calcium hydroxide; other alkaline compounds; and combinations thereof.
Preferably, the additive is a suitable additive to cause an alkalising effect on the acidic water. Preferably, the additive is suitable to cause a reaction in the particulates so that they group or clump together and fall to the bottom. Other forms means of clarifying the water may be used as well as the settling action. Any suitable use of a hydroxide to alter the pH may be used. Preferably, the hydroxide used to reduce acidity or otherwise change the pH also acts to cause contaminants to settle out of the water. Preferably, the invention is used with a settlement pond in fluid communication with the pit water. Most preferably, the water is pumped from the pit to a settlement pond. Most preferably the additive is added through the pump. Most preferably, the addition of the additive is with use of an impeller to thoroughly mix the additive into the water.
Preferably, the additive is added with a mixing step to thoroughly mix the additive into the water. Most preferably, the mixing occurs without disturbance of a settlement pond.
Preferably, a settlement pond is included and water is pumped from the pit to the settlement pond. Preferably, introduction of the additive is between the pit and the settlement pond. Preferably, the introduction of the additive is related to the pumping of the water from the pump to the settlement pond.
Preferably, the water and additive mix is introduced to the settlement pond in a gentle manner, whereby the water is not unduly disturbed. Preferably, water is introduced to a settlement pond through a spray. Preferably, water is sprayed to a settlement pond to minimise disturbance to the water.
Most preferably, water is pumped from the pit to the settlement pond, the additive is introduced with mixing before being sprayed on to the settlement pond.
Preferably, an additional step of settling the water is included. In this water these settled particles can be removed from the water.
Most preferably, the method substantially neutralises the water. Preferably, the resultant water, can be removed from the settlement pond. The water may be pumped from the settlement pond to a holding tank. Preferably, the resultant water is substantially clear water usable for general purposes. Preferably, the resultant water is suitable for aquatic life and wildlife to contact. Preferably, the resultant water has a low risk or impact to the environment. Preferably, the resultant water has reduced mineral content. The reduced mineral content will therefore not impact through staining or otherwise when being used for washing or watering for example.
Preferably, the resultant water is substantially neutral. In other forms of the invention the resultant water is significantly less acidic than at the start. Preferably, the water is brough towards substantially neutral. Preferably, the water may be taken from around pH 2.1 to substantially 7.5 pH . Most preferably, the resultant water is water suitable for other uses. The water may be deemed clear or pure water.
Preferably, use of the invention substantially removes soluble iron from the water. Preferably, use of the invention reduces calcium, nickel and other suspended solid levels in the water.
Preferably, use of the method enables high volume processing of acidic water to usable water. Millions of litres may be processed each day, through use of this invention.
Accordingly, the invention also provides an additive for use to treat acidic water, the additive being sodium hydroxide. Preferably, the sodium hydroxide is used in substantially 10 % solution. Preferably, the 10 % solution will be dosed at a 3.5% of pit water volume. The dosing may be in the range of 2.5% to 12 %.
Accordingly, the present invention provides, in a variant, a method of treatment of contaminated water, the method including the steps of: a) determining the volume of water to be treated; b) measuring additive, to a suitable weight suitable to treat the determined volume of water; c) adding the additive to the water; d) settling the water and additive, whereby the action of the additive on the contaminants in the water reacts causing them to settle out and over time fall under gravity; and e) removal of treated water for use elsewhere, wherein the use of the additive substantially neutralises the acid from the water and removes particulates.
Accordingly, the present invention provides, in a further variant, a method of treatment of contaminated water, the method including the steps of: a) determining the volume of water to be treated; b) measuring additive, sodium hydroxide, to a suitable weight suitable to treat the determined volume of water; c) adding the sodium hydroxide to the water; d) settling the water and sodium hydroxide, whereby the action of the additive on the contaminants in the water reacts causing them to group together and over time fall under gravity; and e) removal of treated water for use elsewhere, wherein the use of the additive substantially neutralises the acid from the water and removes particulates so the water is suitable for use for other purposes.
The contaminants in the water may be anything in the water that it may be useful to settle out through use of the invention. The contaminants may actually be beneficial minerals or particulates that happen to be in the water that it is useful to obtain from the water. The invention may be used to obtain anything suitable from the water, which may be for further use. While generally the contaminants will be just that minerals and particulates acquired during the mine process there could be a wide range of dissolved or suspended things in the water, that it may be desired to obtain and potentially remove. Any one or more of the steps of the method may be omitted. Any one or more of the steps of the method may be reordered in some forms of the invention. The testing test may be omitted and the additive may be used as suitable from previous experience at the site. The volume of water determining step may be omitted, where appropriate. The invention is directed to use for acid mine water but can be used on any water. Should the pH not be acidic, the process will still work to clump and remove the particulates from the water but in this case the pH of the water may become alkali. If this is the case the pH can be corrected to neutral thereafter in the usual fashion before use. Or it is possible that the water to be used is desired to have another pH other than neutral, and in this case the pH can be adjusted to the desired pH. It is anticipated that adaptation and variation may be made to this significant invention to suit a particular use.
The additive may be use of a single chemical additive, or may be the use of any number of suitable additives as may be required by the particular application.
Accordingly, the invention also provides apparatus for use for treatment of Acid Mine Water including a pump and a settlement pond, wherein water is pumped to a settlement pond and additive introduced.
Accordingly, the invention also provides apparatus for use for treatment of water in a pond, the apparatus including: a pump in fluid communication with the pond; a settling pond, able to receive water; and a spray arrangement for spraying water pumped from the pond to the settling pond, wherein additive may be introduced to the water during pumping and the additive acts to reduce the acidity and act on the minerals contained in the water.
Accordingly, the invention also provides, in a variant, apparatus for use for treatment of water in a pond, the apparatus including: a pump in fluid communication with the pond through a conduit; an impeller for mixing water able to act on the water in the conduit; a settling pond, able to receive water; and a spray arrangement for spraying water pumped from the pond to the settling pond from the conduit, wherein additive may be introduced to the water during pumping and the additive acts to reduce the acidity and act on the minerals contained in the water, and clear water may be separated from the settlement ponds.
Preferably, the additive is sodium hydroxide. Any suitable additive may be used. The additive may be any alkalising additive. Preferably, the additive is sodium hydroxide in a 10 percent solution. Preferably the solution is dosed at 3.5 percent of the pit water volume. Other concentrations and dosing may be used and adapted accordingly.
Preferably, the mixing of the additive is introduced with action to encourage the reaction of the additive and the minerals in the water. Preferably, an impeller is used to vigorously mix the additive into the pit water. The impeller may be any suitable means to mix the additive and water. Preferably, the mixing occurs outside of the pit and any settlement pond. Preferably, the mixing occurs during the pumping step. The mixing may take any suitable form.
Preferably, the pump includes a pipe and the mixing occurs in the pipe. Preferably, the mixed water and additive is introduced to the settlement pond. Preferably, the introducing is in any suitable manner. Preferably, the introducing of the water to the settlement pond is gentle, so as not to disturb the already settling water. Preferably, a spray arrangement is included. Preferably, a spray arrangement is included and the mixed water is sprayed onto the settlement pond so as not to disturb the water unduly.
Preferably, a holding tank is included. Preferably, treated water may be removed for use. The water may be removed for further treatment or to a holding tank.
Preferably, the treatment enables rapid treatment of the water and access to clear water within a few hours. Preferably, clear water can be produced through use of the apparatus and method rapidly. Preferably, the quantity of additive used is determined by the pH of the water and calculated water volume or flow rate. Other methods of additional reduction of acidification may be used with the invention. The methods of injecting and or pumping the additive into the water can take any suitable form. Additional method of injecting or pumping the additive into the water can be used, to thoroughly mix the water.
The settled material may contain valuable precipitate. The settled material can be further assessed for valuable and recoverable resources. Preferably, valuable resources may be assessed and considered for recovery. Depending on the nature of the value resource, other methods of recovery may be introduced at this point to obtain the resource.
The apparatus may include any of the features described with respect to the method.
INDUSTRIAL APPLICABILITY
The method is for use to treat acid mine water to enable the neutralised and decontaminated water to be used for other purposes, a useful industrial application. Obtained contaminants from the water may be separated for further use or sale.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described in connection with a non-limiting preferred embodiment with reference to the accompanying drawings, in which:
Figure 1 is a perspective view from the side of a settling pond of the invention according to a preferred embodiment of the invention;
Figure 2 is a schematic of a system arrangement of the preferred embodiment of the invention;
Figure 3 is a cross-sectional view from the front of the impeller of the preferred embodiment, the rest of the apparatus being omitted; Figure 4 is a cross-sectional view from the side of the impeller of Figure 3; and
Figure 5 is a system layout diagram.
DETAILED DESCRIPTION OF THE INVENTION INCLUDING A BEST MODE
Referring to Figures 1 to 5, apparatus 1 is the general reference to all the apparatus used to achieve the method, and the example of the inventive apparatus. Apparatus 1 will be installed at a mine site or similar location where use of the invention is most useful with inflow ring main labelled generally 5. Each mine site will be slightly different as the pit pond, settlement pond and connecting pumps and inlets and outlets will be shaped and sized to suit the particular site. The apparatus will be installed to suit the particular arrangement as would be understood by the person skilled in the art, while maintaining the inventive principles. This very useful invention will be able to be installed in a wide range of applications due to this adaptability.
Pit 10 is shown with settling pond 12 which received water pumped from pit 10 through high capacity pump 14. Settlement pond 12 receives the pit water full of potential contaminants and particulates in the usual way and is allowed to settle. The nature of the water will depend on the surroundings and on the type of mine, but the invention can be applied and adapted to suit the particular needs of the mine type.
Pond discharge pump 16 can be used to remove liquid from the upper part of pond 12, while sludge 18 forms at the bottom and can be removed direct from the sludge area of pond 12 by use of sludge pump 20. Interface 22 is used between sludge suction pipe 24 close to the bottom of settling pond 12, to minimise disturbance as sludge pump 20 is operated to remove sludge 18.
Floats 26 are included on the surface of settling pond 12. Data is collected through use of sensors and these can be used to detect any suitable data. As shown pH is measured throughout the system through use of pH sensors 28. Interface sensors 30 are included to similarly sense conditions at the interface. Chemical dosing system 32 can be seen in particular in Figure 2 as will be used to adjust the pH is response to the system data as described further below. Adjustments can then be made via a control unit (not shown) to adjust the pH to be suitable for use, before the water is pumped out through pump discharge pump 16. The water has been treated to make is usable in other applications around the mine site and so can be used directly or pumped to tank for use later, or moved to elsewhere for use. The control unit has power and through standard actuation can be used to control valves labelled generally 34. The pumps and valves of the system are controlled in the usual manner to open and close and allow or prevent flow of the liquid, as would be readily understood.
Referring to Figures 3 and 4 in particular, detail of impeller 36 is shown with suction/suction eye 38 and vanes 40. Volute casing 42 contains discharge 44 introduced as driving fluid 46, through body 48, with diffuser 50 , nozzle 52, screw 54 and Gasket/O-ring 56. Other forms of impeller could be used instead.
The additive used is sodium hydroxide to treat the Acid Mine Water. Other additives could be used instead, including potassium hydroxide, and calcium hydroxide, other alkaline compounds, and including combinations thereof. The acidic water is not usable in mine pit 10, due to the low pH and dissolved minerals. Therefore, through use of the additive, a strong alkaline solution is created that acts at a concentration capable of causing rapid oxidisation and reaction with the suspended solids. When applied correctly use of the additive acts to react in the solution to cause a precipitate/sludge 18 to form in the water. The created precipitate settles quickly to the bottom of the water of settling pond 12 as a brown sludge, so as to be separated from the clear water. Testing has found the water after the adding of the precipitate and removal of the suspended solids has a light dispersion factor 2. Testing of the water before and after use the inventive method and additive has been undertaken and the results are being gathered but appear to show excellent results to produce clear usable water, suitable and safe to use at the mine site. Amongst the results of the testing is the almost complete removal of the iron, and significant removal of calcium, nickel and other suspended solids. Use of sensors monitoring form a control unit will provide detailed information.
The method of treatment can be used on Acid Mine Water in pit 10 of the mine, where an earthen pond of at least 3 metres is formed. The surface area of the pond will dictate the volume of water that can be treated in a day. Water can be pumped from the pit pond 10 to settling pond 12 and as this occurs the pit water is treated with the solution by introducing the sodium hydroxide solution at 10 % to dose 3.5% of the pit water volume. As the treated water is introduced into the suction side of the pump, impeller 36 thoroughly mixes the solution of the additive into the pit water as it passes through the pump. The mixed water is then delivered to the settling pond, where the coagulation occurs rapidly, as does the settling out of the precipitates.
The mixing delivery at the pump is useful as it means that the mixing occurs separate from the settling ponds and so the settling ponds are not disturbed by the vigorous mixing. To achieve this a ring main of PVC pipe is made to surround the perimeter of the settling pond. The pit water is directed into the ring main which has numerous holes of 12 mm diameter facing the surface area of the pond thus causing numerous small jets of water directed into the air above the settling pond.
Use of the gentle spray application causes the pit water to fall into the settling pond like raindrops and prevents turbulence. The steady state of the settling pond water allows the precipitate to settle to the bottom of the settling pond in less than 4 hours leaving a stratification in the settling pond.
The clear water on the top of the pond can be removed by using a pump with a floating suction line to deliver the water to its destination around the site, the bottom layer of coagulated minerals and sulphates can also be removed by a pump with a bottom of the pond suction line. The resultant precipitate is suitable to irrigate over areas to be reclaimed by mine site revegetation, and is an ideal mineral supplement for growing plants such a native grasses, eucalyptus species casuarinas and all iron loving plants. There is a possible consideration that citrus being iron loving plants would flourish in areas irrigated with this residue.
The additive will cause a Redox reaction in non acidic water also. Precipitate will settle out but pH will become alkali.
Processing the mine water with the additive will be worked out with
Figure imgf000019_0001
injected with the additive at varying
Figure imgf000019_0002
to a point where the mines
Figure imgf000019_0003
is achieved.
The additive can be any of the 34 known
Figure imgf000019_0004
mixed with neutral water giving a pH around pH 13.5.
T ermined
Figure imgf000019_0005
with the mine water to where the
Figure imgf000019_0006
are achieved.
Figure imgf000019_0007
of the m ix to the acid water is between 2.5% to 12% .
Optionally the additive is potassium hydroxide. The additive may in other forms of the invention be chosen from the group: sodium hydroxide; potassium hydroxide; lithium hydroxide; other alkaline compounds; and combinations thereof.
The of water to be treated by the additive is
Figure imgf000019_0008
limited by the size of the d the chemical and the
Figure imgf000019_0009
to transfer the water from the
Figure imgf000019_0010
or
Figure imgf000019_0011
The pit water once treated, clean and neutral, can be further utilised to make the chemical water mix on site to save on transport cost.
The water can be used on
Figure imgf000019_0012
or even
Figure imgf000019_0013
Potable water in more remote areas. Referring to Figure 5 in particular the A system has been devised to treat acid mine water at any mine site as shown in Figure 5 where the labels for the
Figure imgf000020_0001
include:
Suction hose with chemical injection nozzle.
2) Chemical Dosing tank sized to match Transfer
Figure imgf000020_0002
flow rate.
Figure imgf000020_0003
valve controlled by Ph sensor 7 sensor before inlet of Transfer
Figure imgf000020_0004
T ransfer
Figure imgf000020_0005
7) Discharge hose to settling Pond (s).
8) pH meter on discharge Hose for controlling Dosing valve.
9) Ringmain
Pond (s
Figure imgf000020_0006
to Mine services. ion pipe at bottom of
Figure imgf000020_0008
Figure imgf000020_0007
to
Figure imgf000020_0009
out of Settling Pond
Interface sensor to indicate max level of
Figure imgf000020_0010
Figure imgf000020_0011
level.
Principal of Operation
A hose runs form the dosing system to the end of the suction hose in the pit. Chemical is injected continually into the suction hose end in the mine pit water. The intention with the chemical injection is to spray the chemical at a reasonably high pressure so as to start the redox reaction, which reduces the Ph and initiates the settling out of the suspended solids in the mine water.
The chemical is supplied from a storage tank of sufficient size to run the operation for a pre determined time.
The adjustment of the supply of chemical is achieved by a controller at the Ph sensor downstream of the transfer Pump where the Ph should be at its required level.
The controller takes the Ph reading and adjusts the supply of chemical from the dosing valve after the dosing pump. This is occuring continually during the process
At the same time the Transfer pump with a much greater capacity than the dosing Pump will be recieving the mine water, now mixed with the chemical and the Ph will be at the level required.
Passing through the Transfer pump the water and chemical should completely homogenise and the sludge will be starting to settle out with Ph at the desired level.
The Ph meter downstream of the transfer Pump will indicate the Ph at this point.
The mix then enters the discharge ringmain which sits a metre above the Settling pond.
The water mix discharges through many small bore holes aimed down toward the pond designed to form a spray which will prevent disturbance in the setting pond surface which will aid the settling out of the sludge.
The Settling Pond or Ponds are of sufficient size to meet the Mines water demand as required.
We envisage the settling time of a pond of say 100,000Litres may take 4 hours In operation the water usage would be as long as there is clean water above the level indicated by the interface sensor. The interface sensor will sense where the sludge and clean water meet.
This interface is always slightly undulating but rarely more than 50mm
The average level of sludge is in the range of around 15% of the sample or in this case the settling pond.
So as in the case of the 100,000 Litre pond, approximately 85000 L is useable.
At this point both the clear water and sludge are pH neutral at this part of the process and will remain so unless either come in contact with more Sulphides.
At the bottom of the Settling Pond a suction pipe closed at one end and connected by a suction hose to the sludge Pump.
This pipe has multiple holes in the top half by which the sludge can be drawn from the full length of the pit without causing turbulence in the water ensuring a minimal amount of the clear water is taken with the sludge.
The Sludge Pump will remove the sludge back to the pit or to another area if more treatment is deemed necesarry.
One option could be if the sludge settles out quickly, it could be pumped out of the settling pond prior to settling pond being used for its daily services.
The Floating suction is designed to take the clean water from the Settling pond and to ensure the sludge isnt picked up during supply of clean water to mine services.
We envisage the Settling pond filling will be done at night so as the system is ready for a full days work the following day.
The system is completely automated with remote alerting of Ph, system operation, system faults, chemical storage status, precipitate level The method of treatment can be used on Acid Mine Water in a pit of the mine, where a settling pond of at least 4 metres depth is formed.
The surface area of the pond will dictate the volume of water that can be treated in a day.
Acid water can be pumped from the pit pond to the settling pond and as this occurs the pit water is treated with the solution by introducing the hydroxide solution at between 2.5% and 12% to dose the
Figure imgf000023_0001
water The chemical is injected at a point where the suction hose starts in the pit. the time it reaches the suction side of the pump, its pH will be close to or at
Neutral of around Ph7
The now homoqnises the chemical solution and pit water as it
Figure imgf000023_0002
. The mixed water is then delivered to the settling pond, where the clarification occurs , as does the settling out of the precipitates.
All mixing will have been achieved before the
Figure imgf000023_0003
s) and so the clarification of the water and
Figure imgf000023_0004
out of solids is under way as the water enters the ring main. nozzles in the rii
Figure imgf000023_0006
in aimed at the
Figure imgf000023_0005
Figure imgf000023_0007
The water is divided into two separate layers, the top being crystal clear and the bottom being the sludge of the precipitate. is sludge as seen from all our testing is generally 15% of
Figure imgf000023_0008
In this way, use of the additive for a new purpose, and using the turbulent introduction of the additive, and gentle spray introduction the settlement ponds is an important new invention with a multitude of new uses. The resultant clear and usable water will enable this water to be usable at the mine sites for washing and watering, as just some examples. It will be apparent to a person skilled in the art that changes may be made to the embodiment disclosed herein without departing from the spirit and scope of the invention in its various aspects.
REFERENCE SIGNS LIST:
Figure imgf000025_0001

Claims

THE CLAIMS:
1 . A method of treatment for Acid Mine Water, the method including the steps of: a) assessing the water to be treated; b) determining additive to be added to the assessed water; c) introducing the additive to the water before introduction to a settlement pond whereby the additive is mixed with the water and the settlement not significantly disturbed by the introduction of the additive; wherein the action of the additive on the contaminants in the water reacts causing them to settle out of the water in the settlement pond, and substantially neutralises the acid from the water and removes particulates.
2. The method of water treatment of claim 1 , wherein the water treated is Acid Mine Water.
3. The method of water treatment of claim 2, wherein the water to be treated is Acid Mine Water from a pit pond to be directed to a settlement pond.
4. The method of water treatment according to any one of claims 1 to 3, wherein the assessing of the water includes determining the volume of water to be treated.
5. The method of water treatment claim 4, wherein the assessing may be determining the volume of a pit pond.
6. The method of water treatment according to any one of claims 1 to 4, wherein the assessing of the volume is the flow rate of the water.
7. The method of water treatment according to any one of claims 1 to 5, wherein the water to be treated is in a pit pond and flows towards a settlement pond.
8. The method of water treatment of claim 7, wherein the flow rate of water is the flow rate from the pit pond to the settlement pond.
9. The method of water treatment of claim 8, wherein the additive is added to the water flowing between the pit pond and the settlement pond.
10. The method of water treatment according to any one of claims 1 to 9, wherein the assessing of the water includes testing of the water.
11 . The method of water treatment according to claim 10, wherein the testing of the water includes pH testing.
12. The method of water treatment according to claim 10 or 11 , wherein the testing is laboratory testing.
13. The method of water treatment according to any one of claims 10 to 12, wherein the testing includes for any chosen from the following group: minerals; salts; organic materials; contaminants; heavy metals; bacteria; rare earth metals; volatile organic compounds; any chemicals; or any solids.
14. The method of water treatment of claim 1 , wherein the assessing of the water includes determining the volume or flow rate, pH and testing for contaminants.
14. The method of water treatment of claim 1 , wherein the determining of the water is calculating the approximate volume of water in a pit pond.
15. The method of water treatment according to any one of claims 1 ot 14, wherein the water volume is determined so that the additive can be applied to give a 2.5-12% solution or a 3.5% solution result.
15. The method of water treatment according to any one of claims 1 to 14, wherein the additive is sodium hydroxide.
16. The method of water treatment according to any one of claims 1 to 14, wherein the additive is any one or more of the 34 known hydroxides.
17. The method of water treatment according to any one of claims 1 to 16, wherein the additive causes a reaction in the particulates so that they settle out.
18. The method of water treatment according to any one of claims 1 to 17, wherein the additive is added through use of a pump.
19. The method of water treatment according to any one of claims 1 to 18, wherein the addition of the additive is with use of an impeller to thoroughly mix the additive into the water.
20. The method of water treatment according to any one of claims 1 to 19, wherein the additive is added with a mixing step to thoroughly mix the additive into the water.
21 . The method of water treatment according to any one of claims 1 to 20, wherein the mixing occurs without disturbance of a settlement pond.
22. The method of water treatment according to any one of claims 1 to 21 , wherein the water and additive mix is mixed through use of an impeller and then introduced to the settlement pond in a gentle manner, whereby the water is not unduly disturbed.
23. The method of water treatment of claim 22, wherein the water is sprayed gently to add to the settlement pond so as to minimise disturbance to the water.
24. The method of water treatment according to any one of claims 1 to 23, wherein water is pumped from a pit pond to a settlement pond, and the additive is introduced with mixing before being sprayed on to the settlement pond.
25. The method of water treatment according to any one of claims 1 to 24, wherein the method substantially neutralises the water.
26. The method of water treatment according to any one of claims 1 to 25, wherein the resultant water, is substantially clear water usable for general purposes.
27. The method of water treatment according to any one of claims 1 ot 26, wherein use of the method enables high volume processing of acidic water to usable water.
28. The method of water treatment of claim 27, wherein millions of litres are processed each day, through use of this invention.
29. A method of treatment of contaminated water, the method including the steps of: a) determining the volume of water to be treated; b) measuring additive, to a suitable weight suitable to treat the determined volume of water; c) adding the additive to the water; d) settling the water and additive, whereby the action of the additive on the contaminants in the water reacts causing them to settle out and over time fall under gravity; and e) removal of treated water for use elsewhere, wherein the use of the additive substantially neutralises the acid from the water and removes particulates.
30. A method of treatment of contaminated water, the method including the steps of: a) determining the volume of water to be treated; b) measuring additive, sodium hydroxide, to a suitable weight suitable to treat the determined volume of water; c) adding the sodium hydroxide to the water; d) settling the water and sodium hydroxide, whereby the action of the additive on the contaminants in the water reacts causing them to group together and over time fall under gravity; and e) removal of treated water for use elsewhere, wherein the use of the additive substantially neutralises the acid from the water and removes particulates so the water is suitable for use for other purposes.
31 . Apparatus for use for treatment of water in a pond, the apparatus including: a pump in fluid communication with the pond; a settling pond, able to receive water; and a spray arrangement for spraying water pumped from the pond to the settling pond, wherein additive may be introduced to the water during pumping and the additive acts to reduce the acidity and act on the minerals contained in the water.
32. The apparatus of claim 31 , wherein it is used for the methods of any one of claims 1 to 30.
PCT/AU2023/050216 2022-03-30 2023-03-24 Treatment methods, apparatus and additive WO2023183965A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997036829A1 (en) * 1996-03-28 1997-10-09 Geo2 Limited Method for treating acidic waste water
WO2007035981A1 (en) * 2005-09-28 2007-04-05 Jason Ian Nathaniel Beath Contaminated water treatment process
WO2016033637A1 (en) * 2014-09-03 2016-03-10 Global Aquatica Pty Ltd Processing of acid mine drainage water
US10131558B1 (en) * 2016-02-29 2018-11-20 Biosystems Consulting, Inc. Compositions, methods, and/or systems for managing sulfide
US20190218120A1 (en) * 2018-01-18 2019-07-18 Montgomery Chemicals Llc Process for treating mine drainage

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997036829A1 (en) * 1996-03-28 1997-10-09 Geo2 Limited Method for treating acidic waste water
WO2007035981A1 (en) * 2005-09-28 2007-04-05 Jason Ian Nathaniel Beath Contaminated water treatment process
WO2016033637A1 (en) * 2014-09-03 2016-03-10 Global Aquatica Pty Ltd Processing of acid mine drainage water
US10131558B1 (en) * 2016-02-29 2018-11-20 Biosystems Consulting, Inc. Compositions, methods, and/or systems for managing sulfide
US20190218120A1 (en) * 2018-01-18 2019-07-18 Montgomery Chemicals Llc Process for treating mine drainage

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
JEFFREY G. SKOUSEN, ALAN SEXSTONE, PAUL F. ZIEMKIEWICZ: "Acid Mine Drainage Control and Treatment", RECLAMATION OF DRASTICALLY DISTURBED LANDS, 2000, US, pages 131 - 168, XP009549648, ISBN: 978-0-89118-233-7 *

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