FI20206042A1 - Method for treating waste material, arrangement and consolidating binder - Google Patents

Abstract

A method and arrangement for treating and converting mine waste material into a reinforcing binder and utilizing the reinforcing binder. The method comprises heat treating the waste material formed in the bioleaching process and causing it to be converted to a reactive curable material. This material can be used to make a reinforcing binder and to cure and stabilize the waste material to be disposed of in the mining area, or it can also be used in other construction applications.

Description

BACKGROUND OF THE INVENTION The invention relates to a novel solution for the treatment and recovery of waste material.

More specifically, the invention relates to a method and arrangement for treating wastewater, sludge and sludge in a mining area and to a binder made from the waste material.

The subject matter of the invention is described in more detail in the preambles of the independent claims of the application.

For example, the mining industry, the recovery and enrichment of metals generate huge amounts of metal-containing wastewater, sludge and sludge, which require large tanks to treat and are in many ways cumbersome. Various shortcomings have been identified in the water treatment of mines and associated recovery and enrichment facilities.

Brief Description of the Invention The idea of the invention is to provide a new and improved method and arrangement for the treatment of waste material. It is further intended to provide a new and improved binder.

S 25 The characteristic features of the method according to the invention are set out in the characterizing part of the first independent claim 2.

N Characteristic features of the arrangement according to the invention are set out in the characterizing part of the second independent claim.

The characteristics S characteristic of the binder according to the invention are set out in the characterizing part Q of the third independent claim.

The idea of the presented solution is to heat the waste material formed in the bioleaching process of the mine and convert it into a reactive reinforcing substance by heating. Said waste material of the bioleaching process may be wastewater, sludge or sludge. Said heating is a heat treatment step in which the waste material is made reactive.

The advantage of the proposed solution is that the fractions and precipitates formed in the treatment of wastewater can be cured as described in this application in a simple and cost-effective manner. A further advantage is that the hardened materials can be disposed of in piles and holes. The use of such above-ground storage and disposal sites is significantly more advantageous than the placement of liquids in tanks. When the number and size of different pools in the area to be operated can be reduced, large space and cost savings are also achieved.

The storage, treatment and disposal of solid and hardened waste is still significantly safer than the storage of wastewater and other liquids. The risks of rainwater overflows and failure of basin structures can be reduced in the storage and disposal of solids.

The idea of one embodiment is to convert the waste material into a reactive substance by heating alone without any external additives or binders. When no external materials are needed, it is a good solution in terms of logistics and cost-effectiveness.

O The idea of one embodiment is to remove water from the waste material by performing the first heating of the waste material. After the thermal drying, E is further subjected to a heat treatment in which the dried waste material N is activated as a reactive reinforcing agent. Prior to drying, the solids content of the waste material to be treated can be increased by various filtration techniques and by other solid-liquid separation equipment.

The idea of one embodiment is that the waste material to be treated is metal sulphate-containing waste water, sludge, sludge or sludge. In this case, the metal sulfate-containing waste material is heated in the solution so that it becomes a reactive and strengthening binder with water and hydroxides. It should be noted that the enrichment of sulphide ore is typical in the mining industry because many metals are bound to sulphide minerals. The presented solution is suitable for use in connection with several different metal enrichment processes.

The idea of one embodiment is that the metallic waste material formed in the bioleaching process is heated at a temperature of 30 to 300 ° C and under the influence of oxygen.

The idea of one embodiment is that the neutralized waste material formed in the bioleaching process is heated to a temperature of 30 to 300 ° C. Heating can be done under the influence of oxygen. Alternatively, the heat treatment may be performed under oxygen-free conditions or substantially in the absence of oxygen, for example, in a nitrogen-filled furnace, by means of a heat transfer fluid or heat transfer gas, or by some other means.

The idea of one embodiment is to treat a waste material comprising calcium sulphate CaSs0.4, whereby the calcium sulphate is converted on heating to anhydrite, which is a hardening material. The idea of one embodiment is to treat a waste material comprising both metal sulphate Tr and calcium sulphate CaSO, as well as slaked lime N 30 Ca (OH). In this case, the metal sulphate-containing waste material E becomes heat-reactive with water and hydroxides N and reacts and hardens the material, and further, S the calcium sulphate CaSO2 formed in the neutralization changes to heat-treated anhydrite, which is also a hardening material. In this case, the end product of the heat treatment may be a material comprising two or more reactive components. Typically, the metal-containing effluents formed in the bioleaching are neutralized with lime milk made from calcium oxide CaO, i.e., slaked lime Ca (OH), whereby the case of reactivation according to this application is suitable for use in several cases.

The idea of one embodiment is to grind the solid reactivated after the heat treatment into a fine powder suitable for use as a curable binder. Grinding can further improve the reactivity of the material. The powder is also easy to transport, handle and mix with the material to be cured.

The idea of one embodiment is to treat the effluent from the treatment of the effluent of the mine bioleaching process by mixing a binder with the aqueous waste material generated in the mine bioleaching process in one of the ways mentioned above. The binder mixed with the substrate then cures the substrate to a hardness of at least 500 kPa. It is not possible to achieve such hardness without the addition of a binder. For example, the strength of a solid cake formed by filtration alone is at most only a few hundred kPa.

The idea of one embodiment is to produce a binder from the waste material of the mine bioleaching process by heat treatment and to use the prepared binder to cure the same or different waste fraction from the same bioleaching process. The binder may be made of N wastewater, sludge, sludge or sludge, and may cure N sludge, sludge, sludge, sludge or other waste and material containing water and solids. S The idea of one embodiment is to produce a curable binder from one of the following residual materials: pre-neutralization alite, final neutralization alite (LoNe), metal recovery alite (iron precipitate,

RaSa) or alite from a mine water treatment plant. Correspondingly, a binder prepared by heat treatment is used to cure one of the above-mentioned substrates.

The idea of one embodiment is to produce the reinforcing material and binder disclosed herein in the mining area.

The idea of one embodiment is to use the reinforcing material and binder disclosed in this document in the mining area.

The idea of one embodiment is that the solution is directed to an arrangement for the final disposal of waste material in a mining area. The arrangement produces a binder from the waste material formed in the bioleaching process of the mine, which is made into a reactive curable material by heat treatment. The raw material for the production of the binder is thus wastewater, sludge or sludge related to and formed in the bioleaching of metals and its processes. In the arrangement, the binder is mixed with the waste material to be disposed of, whereby the waste material of the mine can be disposed of as a hardened structure or material in the mining area. The cured disposal material is a solid and non-flowing material, making it significantly easier and safer to handle and store than a liquid or other flowing material.

o The idea of one embodiment is to use a curable mixture as the building material of the structure in the mining area, whereby the formed structure is at the same time the final disposal site of the waste material. The idea of one embodiment is to form an rigid and independent structure N rising upwards from the cured waste material or to cure the waste material S by means of a binder into such an upwardly rising N structure. According to the embodiment of N 35 Fra, the above-mentioned structure is one of the following: a pile, a convex

artificial rock, embankment, protective wall, wall or similar stable and self-supporting structure.

According to one embodiment, the structure is laid directly on a flat field in the mining area. Thus, it is not necessary to form the structure in a space surrounded by any protective structure, such as a protective basin.

According to the embodiment, the structure comprises surfaces with a settling angle, i.e. a slope angle, of more than 2.5%.

According to the Fräe embodiment, the structure comprises vertical or steeply sloping surfaces.

According to one embodiment, the largest dimension of the bottom surface area of the structure is smaller than the maximum height of the structure.

According to the embodiment, the maximum height of the structure with respect to the surrounding surface is at least 20 meters.

According to one embodiment, the maximum height of the structure with respect to the surrounding surface is at least 30 meters.

According to the embodiment, the maximum height of the structure with respect to the surrounding surface is at least 40 meters. According to the embodiment, the maximum height of the structure with respect to the surrounding surface is at least 50 meters. o According to the embodiment, the maximum height N of the structure with respect to the surrounding surface is at least 60 meters. 5 According to the embodiment of Fra, the maximum height N of the structure with respect to the surrounding surface is 70 to 120 meters. N 30 According to one embodiment, the floor area of the structure E is less than 1 hectare. N According to one embodiment, the area of the base S of the structure is 1 hectare or more. N According to one embodiment, the structure N 35 is cured from the curable waste material by die casting, sliding casting or 3-D casting.

According to one embodiment, artificial rock or boulders are cast from the curable waste material, which is crushed and the necessary structure is assembled from the crushed stone using earthworks methods and equipment.

According to one embodiment, the infrastructure used in the basic production of the mine is constructed from the curable waste material.

According to the embodiment, one or more stiffeners, such as reinforcements, nets, rods, ropes, fibers, etc., are fitted to the structure.

According to one embodiment, a structure formed of hardened waste material is used as the basis for the energy production equipment. The structure can serve as a platform for a photovoltaic plant or a wind farm, for example.

The idea of one embodiment is to use a curable waste material as a soil material in a mining area.

According to one embodiment, the curable waste material is used as a coating material for a mine road or field.

The curable waste material can act as a substitute for a surface layer formed of, for example, asphalt or compacted natural stone crushed stone. This replacement surface material can also be used outside the mining area, for example in the maintenance, renovation and construction of roads leading to the mining area and other nearby roads.

o According to one embodiment, the curable S waste material is used in the structural layers below the surface of the mine or field. The structural layers N may be frost-protected and run-off-protected. This replacement material can also be used in road structures outside the excavation area, for example in the maintenance, renovation and construction of roads leading to the mining area and other nearby roads. N According to one embodiment, a curable N 35 waste material or a binder made therefrom is used in the mining area to stabilize the soil.

According to one embodiment, the binder prepared in powder form, for example, is transported to other applications, so that it can be used to stabilize moist and poorly bearing soil outside the mining area.

According to one embodiment, a curable waste material or a binder made of the waste material is used to fill the mine shafts, tunnels, open pits or other spaces formed in the removal of rock material with the curable waste material either completely or at least in part.

According to one embodiment, the curable waste material is poured into a lightweight mold structure, such as a geotube. In this case, the geotube or similar film structure is able to keep the cast curable waste material stable until the rapidly curable material reaches sufficient mechanical strength.

According to one embodiment, a structure or material is cast from the curable waste material to be reserved for the subsequent closure and covering of the mining area. Such solid material can be temporarily stored at a suitable location near an object to be landscaped later. When the covering time comes later, a cover layer can be formed of this intermediate stored material, for example on top of gypsum sediment ponds, side rock piles, tailings piles and O other by-product warehouses and disposal sites A in the mining area. Since the covering material is solid and has N mechanical strength, it is also possible to easily form the desired surface forms of N 30 in connection with landscaping. The material E can be, for example, a crush of the desired size, by means of which the desired ditches can be formed in the cover layer and S the inclined surfaces to control the surface and rainwater. In addition to said covering material, it may be necessary to form water-retardant and frost-insulating layers on the object to be covered.

According to an embodiment, said activated binder powder can also be used as a constituent of the structural hardening layer on top of the side rock and concentrate sand piles.

According to one embodiment, the waste material heap stabilized or covered with the binder powder made of the waste sludge can be covered with a waterproof cover layer, for example bentonite, cream solutions and other layers which slow down the flow of water.

According to one embodiment, the curable structural layer prepared with the binder powder can be frost-protected with a heat-insulating soil layer.

The idea of one embodiment is that the disclosed solution relates to a curable binder prepared from a substrate formed in the treatment of wastewater from a mine bioleaching process by heating the material to a reactive form.

The idea of one embodiment is that said binder is in powder form. In this case, after heating, the heat-treated material is ground to the desired particle size, whereby it mixes well in the mixture and is easy to handle and transport.

The idea of one embodiment is that the waste material formed in the above-mentioned processes and situations can be simply and cost-effectively converted into a compressive strength suitable for construction, filling and covering.

The idea of one embodiment is that N 30 of the waste material formed in the above-mentioned processes and situations can be converted into a simple and N cost-effective curable binder which can be used as a binder in the curing of other materials suitable for construction. Binder-curable

N materials can be natural aggregates, crushed natural aggregates, industrial by-products and waste.

The idea of one embodiment is to treat wastewater, sludge or sludge comprising iron and sulphate.

The idea of one embodiment is to treat ferrous sulphate-containing waste water, sludge or sludge.

The idea of one embodiment is to treat wastewater, sludge or sludge containing aluminum sulphate.

The idea of one embodiment is to treat wastewater, sludge or sludge containing metal sulphate and gypsum.

The idea of one embodiment is to treat wastewater, sludge or sludge or pasty material containing metal sulphate and gypsum. Calcium sulfate CaSO; in addition, effluents, sludges, sludges or pasty waste materials may also contain slaked lime, i.e. calcium hydroxide Ca (OH).

According to one embodiment, the solution presented in this document treats an alkaline gypsum-based precipitate formed in the treatment of metallic water, which has precipitated on the bottom of a gypsum basin. The solid in the gypsum sludge basin, which can also be called the final neutralization, settles to the bottom of the basin and free water is formed on the surface. The gypsum sludge pool has a high water content of N, typically 80-85%. N 30 According to one embodiment, the gypsum precipitate E is transferred to the disposal area by pumping along the discharge pipe. During the transfer, the reactive curable binder disclosed in this document S is mixed with the gypsum precipitate, whereby the gypsum precipitate hardens in the disposal area. The idea of one embodiment is that the curable material or powder formed in this document can be used to form a curable structure without the addition of any external binder. As such, the reactive material shown provides a curing reaction with water and sufficient compressive strength for a variety of applications. In other words, the binder and the water or hydroxide can be made into a curable structure as such.

According to one embodiment, the curable material or powder disclosed herein is used as a binder which is mixed with the material to be curable or stabilized from 0.5 to 80% by weight of the total weight. This already provides a compressive strength of several MPa.

According to one embodiment, the curable material or powder disclosed herein is used as a binder, and the material to be cured with the binder is a solid mining waste or soil material.

In one embodiment, the curable material or powder disclosed herein is used as a binder, and the binder-curable material is a liquid, sludge, or sludge-like mining waste.

According to one embodiment, the curable material disclosed herein or the material or structure cured therewith is water-insoluble or substantially insoluble. The cured material also binds well any heavy metals and other contaminants in the starting materials and thus reduces their dissolution and release into the environment.

According to one embodiment, the curable material disclosed in this document 5 or the material or structure cured therewith has a compressive strength of at least 0.5 MPa.

E According to one embodiment, the curable material N or the material or structure cured therewith in this document N has a compressive strength N of at least 1 MPa.

OF

According to one embodiment, the curable material disclosed herein or the material or structure cured therewith has a compressive strength of at least 2 MPa.

According to one embodiment, the curable material or cured material or structure disclosed herein has a compressive strength of at least 3 MPa.

According to one embodiment, the curable material disclosed herein or the material or structure cured therewith has a compressive strength of at least 4 MPa.

According to one embodiment, the curable material or cured material or structure disclosed herein has a compressive strength of at least 5 MPa.

According to one embodiment, the curable material or cured material or structure disclosed herein has a compressive strength of at least 10 MPa.

The idea of one embodiment is that waste heat and energy generated in a mining area or in a nearby production plant can be used for both heat drying and actual heat treatment.

Furthermore, it is possible to utilize the electricity produced by wind energy in the heating, as well as the solar energy as such directed by means of N lenses, converted into electricity by means of solar cells or by the heat produced by various other solar collectors Tr. N 30 = a N Heating and activation S The following are some observations from the N experiments performed and the phenomena that have occurred or are assumed in them. N 35

Heat treatment of the metal sulfate-containing waste material generated in the neutralization processes of the bioleaching process under oxygen-containing conditions appears to activate the waste material and convert it to a water-reactive or other hydroxide-reactive material. It has also been found in experiments that when the activated material is subsequently mixed with water or a solution containing one or more hydroxides, it forms a mouldable and reinforcing mass.

In experiments, the waste material has been heated to different temperatures. Temperatures of 30 to 300 ° C have been used, depending on the metal compound contained in the waste material. For example, for a material containing ferrous sulfate, it has been found in experiments that a suitable heating temperature is 100 to 180? C. The appropriate heating temperature has also been found to depend on the amount of impurities in the starting material. By raising the temperature, it has been found that the processing time can be shortened. On the other hand, by extending the treatment time, the heat treatment can be performed at a lower temperature.

In experiments, it has been found that it makes sense to heat for a thin material thickness so that it has a large surface area under the influence of heat and the surrounding oxygen. The waste material to be treated can be applied to the planar surface in a thin layer during the oxidation treatment.

N As an alternative to the planar heating described above, the material can be mixed during heating. In this case, the N material is exposed to the oxygen-like effect of heat and oxygen during the heat treatment. In this case, it may be possible to shorten the processing time and lower the temperature.

3 An alternative heat treatment technique is a bubble fluidized bed, circulating fluidized bed, and fluidization process implemented with a heat transfer gas or heat transfer fluid.

Heat transfer to the waste material can also be carried out on direct heat transfer surfaces without the presence of a medium.

The experiments also showed that it is possible to carry out the heating at an ambient oxygen concentration higher than the normal atmospheric oxygen concentration, if necessary, in order to enhance the oxidation.

It was further found in experiments that if the waste material to be treated contained calcium sulfate, the heat treatment could be performed under anaerobic or low oxygen conditions, and still a reactive material was obtained which was later cured when mixed with water or moist waste material.

The activation in this case could not be considered to be based on oxidation, but was a change in the structure of the calcium sulphate caused by heating.

Increasing the dry matter content The idea of one embodiment is to increase the dry matter content of the waste water, sludge or sludge before the heat treatment.

In this way, the aim is to increase the metal content, the calcium sulphate content or both of the waste material before heating.

In addition, the actual heat treatment time can be shortened if the starting material o is well pre-dried.

S The following techniques N and equipment, and combinations thereof, may be used to increase the dry matter content and dewatering of the waste material: N 30 - Mechanical dewatering or drying, for example by centrifugation of E, whereby water is removed from the solid N by centrifugal force. 3 - Mechanical water separation, in which free water is removed by vibration, compression or compaction.

- The devices for mechanical dewatering are the above-mentioned centrifuge and the screw press, the filter belt press.

- Drying can also be carried out with the following devices: a wire-type filter (strip filter), a vibrating screen, a gravity filter, a pressure filter, a centrifugal filter (centrifugal filter), a reverse osmosis filter, a membrane filter, a pressure filter, a vacuum filter.

- Dewatering by filtering the filter unit with filter cloths or strainers. Filter equipment includes belt filters, disc filters, drum filters, plate filters and filter equipment used in the paper and mining industries. Filter devices utilize a differential pressure, typically a vacuum.

- Drying can also be done using geotubes or geosacks. In this case, the substance to be treated is fitted inside the tube or bag and the liquid is gradually removed and the solid remains.

- Water separation can also be done with ultrasound. By applying ultrasound to the slurry or precipitate, water and solids are separated.

- Drying and activation o may be preceded by an increase in solids content by some N acoustic techniques. This may be, for example, an acoustic resonance basin. Acoustic N resonance can also be utilized below ultrasonic frequencies. E - In precipitation, the solid N contained in the slurry is gradually allowed to settle to the bottom of the precipitation basin. The clear water remains in the surface part of the precipitation basin, from where it can be pumped to the water treatment plant for further treatment. A precipitate with a higher solids content can be taken from the bottom or bottom part of the settling tank. The material can be taken in, for example, by means of suction equipment. The suction dredging device for treating beaches can be modified to be suitable for the purpose.

- Dewatering can also be done by evaporation. Evaporation is especially suitable when large pools or solar energy are available.

- In thermal drying, water is evaporated at an elevated temperature. In other words, the dry matter content of the sludge is increased by heat. For example, steam or flue gases can be used for drying, if available in the mining area.

Grinding In the experiments performed, the solid reacted by heat treatment was ground to a fine powder.

In the experiments performed, it was found that the reactivity of the formed material could be further increased by grinding and other mechanical treatments. Mechanical treatment was found to improve the reactivity of the material itself, and in addition, the reaction area of the fine powder particles is large and mixing in the mixture O is efficient.

Bonding N In experiments, it was found that the material or powder N reactivated as described above reacted with water to form a strong bond when dried. S When the reactive material is subsequently mixed with water or other one or more hydroxides

N-containing solution so, it formed a strong bond.

For example, it was found in the experiments that the curing reaction was induced by potassium hydroxide and calcium hydroxide.

Without lime The idea of one embodiment is that by using the solution presented in this document for curing the material with a reactive substance formed from wastewater containing metal sulphate, it is possible to dispense even the lime, lime milk or gypsum treatment of the wastewater.

It is clear that this allows for significant cost savings.

Wastewater containing metal sulphates generated in the mine's bioleaching process is typically neutralized with lime during the mine's wastewater treatment.

In this case, calcium hydroxide Ca (OH), i.e. slaked lime or lime milk, is mixed with the effluent containing sulfuric acid H2SO4 generated in the bioleaching process.

If the use of lime can be avoided or reduced, there are significant logistical and economic benefits.

Use of Reactive Material Reactive material made from mine metal sulfate-containing wastewater, sludge, sludge, or clay waste material can be used in a mine and mining area in a number of N ways.

In other words, in the manner described in this document, a material that is difficult to handle and harmful to the environment can be converted to a less hazardous form and the remaining material can even be converted into a useful building material. for the construction of other infrastructure.

N According to one embodiment, the cover material N 35 - can be cured into a cover material which can be stored for later use.

When mining and metal recovery in the mining area are sometimes stopped later, the mine, mine structures, mine equipment, and the mine environment can be covered and landscaped. The cured material can thus be stored easily and safely for mine closure.

According to the embodiment of the mill, the holes or piles of the curable material can be cast, i.e. certain types of artificial rocks, which can later be broken and crushed into crushed or boulders. With the help of such hardened waste material, e.g. mine gypsum sludge ponds, sewage ponds, settling ponds and other liquid storage ponds, as well as structures used for precipitation. The cured material can also be used to cover and seal solid storage sites in the mining area. The material can be used to cover side rock piles, for example.

According to one embodiment, it is also possible to mix the reactive material disclosed herein with wastewater or any material containing water or one or more hydroxides and to apply this curable pumpable mixture to the desired layer thickness over the objects to be covered. If necessary, the machining and hardening properties of the mixture thus prepared can be adjusted by adding slaked lime Ca (OH), gypsum CaSO; or quicklime CaO. The reactive material causing the curing can be mixed by means of a wastewater mixing device, for example during or in connection with the transfer pumping. The agitator device can be adapted as an extension of or in connection with the discharge pipe N 30 of the settling tank. It is also possible to pump the effluent E or the like from the settling tank to the tank truck, to mix the active binder with the effluent to be transported, to transport the cargo to the unloading coverage area and to pump and apply the curable mixture to the coverage area as a protective layer.

According to one embodiment, it may be justified in some cases to apply a reactive curable material directly to the effluent or other waste material in the pool, in which case the curing is carried out in situ in a settling tank or the like. In this case, a curable binder, for example a powdered reactive material, is applied to the water in the tank and at the same time mixed with a stirrer. If necessary, the machining and hardening properties of the mixture thus prepared can be adjusted by adding slaked lime Ca (OH), gypsum CaSO, or quicklime CaO to the mixture. In this solution, the basin becomes a final disposal site for wastewater or sludge. After treatment, the pool comprises a hard solid instead of a fluid.

According to one embodiment, the curable activated waste material presented in this document can be utilized in the so-called in pasta filling, where filler is pumped into decommissioned mining corridors, shafts or corridors or spaces required by the excavation process to strengthen their structure. If necessary, the machining and hardening properties of the mixture thus prepared can be adjusted by adding slaked lime Ca (OH), gypsum CaSO, or quicklime CaO to the mixture. Paste filling can also be used in situations where it is necessary to strengthen the rock next to the object to be excavated before excavation can begin.

The method of said paste filling can be a combined filling, which utilizes both the extracted side rock and the hardening N 30 binder made from the waste sludge of the bioleaching process.

E The use of the curable material N disclosed in this application as a binder for a paste filler is preferable because S can be cured very rapidly. This avoids long waiting times and can only be resumed next to the filled N 35 cavity or space after a short interruption.

In addition, it is advantageous that the material formed in the mine area from the mine's own process can be used as a binder and it is not necessary to introduce any external ingredients in the production of the filling paste. This is very logistically efficient.

According to one embodiment, it is possible to use a pumpable fluid or paste curable by the reactive material or binder disclosed herein to produce various support and protection structures using a slip molding technique. Sliding casting is made possible by e.g. the sensitive flowability of the material before curing and the rapid curing after casting. If necessary, the machining and hardening properties of the mixture thus prepared can be adjusted by adding slaked lime Ca (OH)>, gypsum CaSO, or quicklime CaO to the mixture. The material is still suitable for 3-D printing of structures, for example by means of a casting head movable on a robot arm. Said sliding casting and 3-D printing are suitable, for example, for the construction of edge walls for precipitation and water treatment tanks. Sliding casting and printing techniques can also be used to install cover structures, making it possible to produce large, uniform protective structures that are well protected, e.g. rainwater. A temporary support structure can be arranged on top of the gypsum sink basin or the like, from which the deck structure can be cast.

o Alternatively, a lightweight mobile casting system can be used to cast on the pool, for example by spraying or using conveyors.

N 30 Some examples of experiments performed j N Example 1: 3 In the experiment, sludge settled to the bottom of the mine's gypsum sediment basin was taken. The slurry was green in color due to the ferrous sulfate Fe, SO 5 presumably contained in N 35. The slurry was heated in an oven at 180? C at which time the water was first evaporated. The dry matter content increased to 40% by weight by evaporation. The paste-like mass formed after the evaporation step was applied to a flat vessel in a thin layer of about 10 mm, after which it was heated in an oven at 180 ° C for 4 hours. Upon heating, the mass turned to a brown crumbly plate. The color of the pulp after oxidation was characteristic of rust brown. The formed pulp sheet was crushed and ground in a grinder to a fine powder. The heat-treated and homogenized waste material was found to be reactive with water and hydroxides and to strengthen.

Example 2: The powder prepared in Example 1 above was mixed with pure water to give a curable mixture.

Further attempts were made to mix the powder into the effluent taken from the gypsum sludge tank, which was also made hardened by means of a reactive powder.

In a similar manner, the powder was used to harden the precipitate taken from the bottom of the gypsum precipitate basin.

It was found that even after a curing time of half an hour, the compressive strength of the cured mass was about 10 MPa. The compressive strength did not increase significantly from this value with increasing curing time. o In one experiment, a reactive binder N was prepared from the N metal sulfate-containing waste sludge of the gypsum sludge basin by first removing water and then by heat treatment. When this prepared binder was taken up in 1/3 t-volume and the corresponding sludge containing 3/3 of the metal sulphate E-containing gypsum sludge basin and mixed with them with said N mixture ratio, the mixture was cured to a compressive strength of 10 MPa S. Thus, in the experiment, the waste sludge was first made into a binder and then the same waste sludge was cured with N 35 binder. Such self-curing was found to be a very interesting solution for the treatment of waste sludge.

Further experiments were performed with several different powders prepared from starting materials with different metal sulfate concentrations before the heating step.

The test pieces were further tested for solubility in water. The cured specimens were found to be insoluble or sparingly soluble in water. The starting materials had heavy metal concentrations, but these were not found to be significantly dissolved in the dissolution experiments.

Based on the experiments, it can be stated that the reactive powder formed can be used as a curable binder, for example, in the stabilization and curing of aggregate fractions. Furthermore, the powder can be used to harden the fines in the metal processing of the mine's wastewater treatment or even directly in the wastewater.

Example 3 Moisture and pH were measured from the waste sludge (solids content 15-65% wet weight and pH ranged from 5.0 to 9.0).

The waste slurry (precipitate) was mixed evenly with a whisk and dried and heat treated at 105 ° C (1 day) in the presence of an oxygen-containing gas mixture. The dried solid was triturated and homogenized to a powder. In this way, a binder powder which is activated with water and waste sludge is obtained. The experiment was repeated at different temperatures between 30 and N 245 ° C and it was found that the required treatment time depends on the temperature used. The binder properties E of the powder also become less favorable if the treatment is carried out below NV at 80 ° C or above 200 ° C. 3 N Example 4 N 35 A solid was prepared from a binder powder prepared from a sample batch of waste sludge by adding water at a temperature of about 18 ° C (2 parts powder and 1 part water). At this alloy ratio, the workability time for casting into a prism die casting mold was found to be 2 minutes as measured from the time of water addition. The pulp made of binder powder and water warmed considerably during the initial solidification. The compressive strength measured from the Prisma compression specimen was 6.86 MPa (measured from a 28 day old compression specimen). When the experiment was repeated with the same binder powder from the same waste sludge sample and the same powder to water ratio, the workability time varied from 1 to 4 minutes depending on the temperature of the ingredients to be mixed (between 0 ° C and 60 ° C), vibration intensity and mixing homogeneity.

When the test was repeated with binder powders made from different batches of waste sludge and with water, the workability during casting into a prism die mold varied from 30 seconds to 60 minutes depending on the vibration intensity, powder-water ratio, alloy temperatures (0 ° C to 60 ° C) and depending on the homogeneity of the mixture. Compressive strength results from 28-day-old prism specimens have been measured to be between 0.5 and 10 MPa depending on the recipe. The workability time and the final strength were found to depend on the chemical composition of the waste sludge sample used in the preparation of the powder.

N Example 5 o LSIMer kil 9 A The curable powder N was also prepared from the waste sludge from an E slurry concentrated almost or completely clay-like (i.e. N 30 with a solids content higher than the waste sludge sample). Concentration, i.e. raising the solids content N, was performed by gravity and pressure filtration. S Filtration was enhanced by acoustic resonance and mechanical vibration of the filter cake. The concentrated slurry was heat treated at 105 ° C for 1 day in the presence of an oxygen-containing gas mixture.

The waste material activated by the heat treatment was comminuted and ground into a homogeneous powder mechanically, and the powder thus prepared had similar hardening and machining properties as the thermal drying and heat treatment alone mentioned earlier.

Example 6 A solid was prepared from a powder prepared from a sample batch of a sludge by adding to it a sludge sample representative of the same sludge used in the preparation of the powder at 18 ° C (1 part powder and 2 parts sludge at 20% solids). With this mixture ratio, the workability time for casting into a prism die casting mold was found to be 3 minutes from the start of mixing the waste slurry and powder. The pulp made of binder powder and waste sludge warmed considerably during the initial consolidation. The compressive strength measured from a prism-type 40 x 40 x 100 mm compression test piece was 1.61 MPa (measured from a 28-day-old compression test piece).

When repeating the experiment with a powder prepared from the same batch of sludge and the same powder-to-slurry ratio, the workability time varied from 1 to 10 minutes depending on the temperature of the ingredients to be mixed (between 0 ° C and 60 ° C), vibration intensity and mixing homogeneity.

o When repeating the test with powders prepared from different batches of waste sludge N and with untreated waste sludge, the workability time varied between 30 seconds and 60 N minutes depending on the intensity of vibration, powder-waste sludge ratio, sludge solids content, E mixture temperatures 60 ° C) and depending on the homogeneity of the mixture N. Compressive strength results from 28-day-old S-prism specimens have been measured to be between N 0.5 and 5 MPa depending on the recipe. The workability time and the final strength of N 35 were found to depend on the chemical composition of the waste sludge sample added to the powder and on the solids content of the waste sludge.

Example 7 The powder and the sludge were made into a solid by adding concentrated sludge (in clay form) to the powder at a dry matter content of more than 40% in a mixing ratio of 1 part powder and 5 parts concentrated sludge). The body prepared in this way achieved similar workability and hardening properties as the powder and the untreated slurry. The pulp made of binder powder and concentrated waste sludge warmed considerably during the initial solidification.

When the experiment was repeated with the same powder-concentrated broth ratio, the workability time varied from 1 to 10 minutes depending on the temperature of the ingredients to be mixed (between 0 ° C and 60 ° C), the intensity of vibration and the homogeneity of the mixture.

When repeating the experiment with powders made from different batches of waste sludge and with concentrated waste sludge, the workability time varied from 30 seconds to 60 minutes depending on the vibration intensity, powder-sludge ratio, solids content of the sludge, mixing temperatures (0 ° C to 99 ° C). depending on homogeneity. Compressive strength results from 28-day-old N prism specimens have been measured to be between 0.5 and 5 MPa depending on the recipe. The workability time and the final strength of N were found to depend on the chemical composition of the waste sludge sample added to the powder in the preparation of N 30 powder and on the solids content of the concentrated N waste sludge.

3 N Example 8 N 35 When testing the binder properties of a heat-treated powder made from waste sludge in stabilizing the soil,

it was found that dredged material, peat, silt, clays, crushed stone and gravel, among others, are stabilized in the same way as commercially available binders used in soil stabilization.

Example 9 When testing the binder properties of a heat-treated powder made from waste sludge, it was found that the slag, tailings and side rock fractions of the waste incineration plant are also stabilized. . Example 11 In a freeze-thaw test, it was found that the duration of the test made of binder powder and water from waste sludge was 12 freeze-thaw cycles before the body crumbled. Definitions of Some Terms Mention should be made of the terms used in this document: N - Waste water is disused water with harmful amounts of foreign matter. In this application, waste water refers in particular to industrial waste water and mining water. Water is used in mining, mining and enrichment of ore S and possible further processing. Mining water includes process water circulating in the mining process, water removed from the quarry and runoff from the mining area.

- The precipitate is an impurity accumulated on the bottom of the liquid. - A slurry is a mixture of a liquid and a solid, finely divided material mixed with it.

- Alite is a solid substance separated from a liquid by filtration, precipitation or other separation method.

Bioleaching The proposed solution is used especially for the treatment of wastewater generated in bioleaching and the sludge deposited from it. Bioleaching is an enrichment process in which metals are removed from ore by microbes. The bioleaching process creates optimal conditions for microbes that occur naturally in the soil, whereby microbial activity catalyzes the oxidation reactions of metal sulfides. Bioleaching can be bioheap leaching, but the proposed solution is of course suitable for use in mines utilizing other bioleaching processes. In bioheap leaching, favorable conditions for bacterial activity are created in the leach heaps by wetting the heaps and blowing air into them. The heaps are thus aerated and irrigated with an acidic (pH 1.5-3) solution on top of the heap by means of irrigation tubes so that the bacterial activity N can be accelerated. Bacteria separate metals from ore by catalyzing the oxidation of iron and sulfur in the ore to provide energy for its growth. N 30 The main processes in the production process are: mining, E crushing, agglomeration, bioheap leaching and metal recovery. 3 After agglomeration, the ore is piled into 6-12 meter N high piles where it is dissolved for 1-3 years. N 35 In bioleaching, the metal sulphides contained in the ore are oxidized to soluble compounds by microbial activity.

The main reaction for metal recovery is: Metal sulphate (MeSO 4) + Hydrogen sulphide (HS) - Sulfuric acid (H 2 SO 4) + Metal sulphide (MeS) In the iron precipitation step, the pH of the solution is raised by means of limestone slurry. The precipitation of the final neutralization step is carried out by raising the pH of the solution to a clearly basic level (pH = 10) with lime milk (Ca (OH)), which allows the precipitation of residual and other metals as hydroxide. The slurries of the thickeners are pumped to a gypsum basin, where the gypsum precipitate settles and the clear solution is pumped back to the leach heaps in due course through solution cleaning. The bottom of the final neutralization can be led to a gypsum sump. The main reaction of the final neutralization (LoNe) is: Metal sulphate (MeSO 4) + lime milk (Ca (0H),) - Gypsum precipitate (CaSO, x HO) + metal hydroxide Me (OH): The presented solution can be used to treat and fines.

o The above embodiments and the features presented therein can be combined to provide the desired solutions. N BRIEF DESCRIPTION OF THE DRAWINGS = 30 Some embodiments of the presented solution are shown in more detail in the following figures, in which Figure 1 shows a schematic and simplified diagram N for the treatment of bioleach waste.

Fig. 3 shows schematically and in a simplified diagram the production of a binder from a waste material and the use of a binder, Fig. 4 schematically shows some structures and applications made of curable material in a mining area, in connection with the waste water discharge pipe, a mixing device is arranged for mixing the binder, and in which the waste material is conveyed to the pool after curing; and Figure 7 is a schematic and side view of a very tall structure in which cured waste material can be disposed of.

For the sake of clarity, some embodiments of the presented solutions are shown in simplified form in the figures.

In the figures, the same reference numerals are used to refer to the same elements and features.

DETAILED DESCRIPTION OF SOME EMBODIMENTS Figure 1 shows the steps for converting wet waste material from bioleaching to a binder and how the prepared binder can be utilized in the mining area.

The waste material 1 can be pretreated 2 to increase its N dry matter content using various filters, separation equipment and thermal dryers.

The activation of the waste material into a reactive material takes place by means of the heat treatment 3.

In the heat treatment, the waste = 30 materials are heated in an oven or similar heating device.

After heating and activation, the cured S material can be ground to 4 fine powders.

The prepared powder can be used as a binder 5, by means of which N it is possible to harden the waste materials formed in the mining area as well as any other ingredients.

The binder can be mixed with the aqueous waste material in a suitable ratio, whereby the water in the waste material activates the reactive binder and causes the waste material to cure. Due to the curing, the waste material can be used as a building material, i.e. the problematic waste material can be disposed of in the mining area 6 as a hardened utility structure. It can be used to build mining infrastructure 7, upward-rising hardened structures 8 and various protection structures 9.

Figure 2 illustrates the heat treatment 3 of the waste material 1. The waste material 1 to be treated may be metal-containing, whereby activation of the metal sulphate 10 may occur when the heating is carried out in the oxygen-containing state 11. If the waste material 1 to be treated comprises gypsum, conversion of sulphate sulphate 12 to a substance which reacts and strengthens with water or other hydroxides. During heating, one or more other reactions may take place which cause or contribute to the formation of a reactive curing agent. 13. In any case, practical experiments have shown that

13.

Figure 3 illustrates that the waste material 1 can be formed into a curable binder by means of the binder preparation 14, which can be used to cure a waste material 15 or different from that from which the binder itself is made. Furthermore, the binder can be used to cure any natural soil 16.

N Figure 4 shows some applications. The curable material can be made into a embankment 17 N or a rampart, which can be used, for example, as a pool edge N 35 or as a protective structure. If necessary, the machining and strength

can be adjusted by additional material, for example gypsum CaSO1, slaked lime Ca (OH), or quicklime CaO.

Furthermore, a solid hard hill or pile 18 extending upwardly from the curable material can be cast, which remains firmly in place and upright without external structures.

It is further possible to form a pile of crushed stone or boulders formed by first casting a hard structure, for example artificial rock, and crushing it into crushed stone or boulders after final hardening.

Utilizing various casting techniques, the curable material can also be used to form walls 19 and other support and foundation structures.

It is possible to strengthen the soil by using the curable materials disclosed in this document to stabilize the soil.

The cured material shown can also be used as a coating 21 and surface layers for the mine and its surroundings on roads and fields.

It can also be seen from Figure 4 that the upwardly directed structures 17, 18 and 19 can be formed directly on the planar surface 22.

Figure 5 shows a basin 23, which may be, for example, a gypsum sediment basin.

The edges of the basin 23 have embankments 17 which may be formed of the curable material shown.

The final covering of the basin 23 can be done by casting a lid 24 on the material to be cured. Fig. 6 shows an arrangement in which a mixing device 27 mixing the curable binder with the feed material 28 E in the discharge tube 26 with the waste material to be transferred, whereby a curing reaction begins in the waste material.

S The waste material can be discharged into a basin 23 or other disposal site where it can still be controlled while still in the flowing state.

However, curing takes place quite quickly.

The curable waste material can be sprayed or applied in a thin layer to the entire disposal site by means of suitable nozzles 29. The disposal site may be a final disposal site or, alternatively, the cured solid material 30 may subsequently be broken and crushed into, for example, crushed and transported for use in or near the mining area as an earthworks or cover material. In this case, the same pool 23 or the like can be used as a receiving point for the recurable waste material after the removal of the solid.

Figure 7 shows a liner 31, pile or the like formed of a curable waste material. The height h of this hardened structure from the surrounding surface is several tens of meters. The height is thus at least 20 m, but preferably it has a height of at least 50 m and even 100 m, or more. Due to the cured material, very large amounts of waste material can be stored or disposed of in such a very high structure compared to current landfills. The sides of the structure can be staggered 32 taking into account occupational safety and disposal technical considerations. In the case of final disposal, soil, bentonite, various films, nets, creams and geotextiles may be applied to the structure, which may be intended to contribute to the landscaping, anti-weathering, water management or other aspects of the structure. These above-mentioned materials and components can be combined in the desired manner into a suitable cover layer 33. The above-mentioned stepping 32 can also participate in and facilitate the installation and retention of the cover layer.

N 30 Note that in Fig. 7 the relationships of the dimensions E of the structure to each other are not necessarily shown N on the correct scale.

3 N The figures and their description are intended only to illustrate the idea of the invention. However, the scope of the invention is defined in the claims of the application.

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Claims (15)

Patent claims A process for treating waste material, in which process processes waste material which arises in a bio-leaching process in a mine and which consists of waste water, sludge or an underflow, and the waste material is heated to convert it into a reactive hardening substance, characterized in that from the waste material from the bio-leaching process in the mine, a binder is produced by the heat treatment and the binder produced is used to cure the same or another waste fraction from the same bio-leaching process. Process according to Claim 1, characterized in that the conversion of the waste material into the reactive substance is carried out only by heating without any external additives. A method according to claim 1 or 2, characterized in that a first heating of the waste material is performed to remove water from the waste material; and the heat treatment is continued after the drying for S to activate the waste material to the reactive hardener & blank. Process according to one of the preceding claims 1 to 3, characterized in that N is the heat-treated waste material containing metal sulphate such that the metal sulphate compounds therein are activated N to a material which reacts and cures with water and N hydroxides. . Process according to one of the preceding claims 1 to 4, characterized in that the waste material containing metal sulphate is heated at a temperature of 30 to 300 ° C and under the influence of oxygen. Process according to one of the preceding claims 1 to 5, characterized in that waste materials containing metal sulphates and calcium sulphate CaSO 4 are treated, the calcium sulphate being heated on heating to an anhydrite which is a hardening material. Process according to one of the preceding claims 1 to 6, characterized in that the solid activated by the heat treatment is ground after the heating treatment into finely divided powder which is suitable for use as a curing binder. A method according to any one of the preceding claims 1-7, characterized in that an underflow arising in a bio-leaching process in a mine is treated by mixing in it binders prepared according to any one of the preceding claims 1-7, wherein the binder cures said underflow to a hardness of at least 500 kPa. SO 9. An arrangement for final disposal of waste material in a mining area, characterized in that binder is produced from waste material, which N arises in a bio-leaching process in a mine and which consists of waste water, sludge or an underflow, and which N is converted by heat treatment to a reactive N curing agent; the binder is mixed into the waste material to be disposed of; and the waste material from the mine is disposed of in the mining area in the form of a hardened structure or hardened material; and wherein said waste material being disposed of consists of the same waste material that has arisen in the bio-leaching process in the mine and from which said hardening binder is produced. Arrangement according to Claim 9, characterized in that the hardening mixture is used as building material for a structure in the mining area, the structure created being at the same time the final disposal site of the waste material. Arrangement according to Claim 9 or 10, characterized in that a raised rigid and independent construction is created from the hardening waste material. Arrangement according to one of the preceding claims 9 to 11, characterized in that the hardening waste material is used as soil material in the mining area. S O 13. A hardening binder made from Tr waste material; Characterized in that the E binder is prepared from an underflow or N a filter cake containing metal sulphate and which has formed S in the treatment of waste water from a bio-leaching process in a mine by heating the material to a reactive form, and which binder is intended to be used to harden waste materials from the same bio-leaching process. Binder according to Claim 13, characterized in that the treated material has been ground after heating, the binder being in powder form. Binder according to Claim 13 or 14, characterized in that the binder is designed to react when mixed with water or another liquid with an OH group and to effect a curing reaction. N O N O O I a a N + O © O N O N