FI129403B - Method for treating waste material, arrangement and consolidating binder - Google Patents

Abstract

A method and arrangement for treating waste material from a mine and for converting it into a curing binder and for utilizing the curing binder. The process heat-treats waste material that arises in a bio-leaching process and causes it to be converted into a reactive hardener. From this substance a hardening binder can be produced, and with the help of it one can harden and stabilize final disposal waste material in the mining area, or one can use it for other construction engineering 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. The following publications provide solutions for the treatment of waste materials: CN-106630712-A; CHAN, B.K.C. et al. Cemented products containing waste from Mineral processing and bioleaching. In: Minerals Engineering, Vol. 22, 1326-1333. 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. The characteristic features of the method according to the invention are set out in the characterizing part of the first independent claim. S Characteristic features of the arrangement according to the invention are set out in the characterizing part of the second independent claim.

The characteristic features of the binder according to the invention are set out in the characterizing part 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 that the conversion of the waste material into the reactive substance P is carried out by heating alone without any external N 30 additives or binders. When no external materials are needed, E is a good solution in terms of logistics and cost-effectiveness. S The idea of one embodiment is to dewater the waste material by first heating the waste material. After thermal drying, a further heat treatment is performed, in which the dried waste material is activated to 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 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 30-300 ° 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.

N The idea of one embodiment is to treat N a waste material comprising calcium sulfate? Casoa, in which case calcium sulphate is converted on heating to N 30 anhydrite, which is a hardening material. E The idea of one embodiment is to treat N a waste material comprising both metal sulphate S and calcium sulphate CaSO, as well as slaked lime N Ca (OH). In this case, the metal sulphate-containing waste material N 35 is converted into a material which reacts and strengthens with water and hydroxides during the heat treatment, and further,

the calcium sulphate CaSO formed in the neutralization is converted to anhydrite on heat treatment, which is also a strengthening reactive 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 N of a solid cake formed by filtration alone is only a few hundred kPa at most.

The idea of one embodiment is to prepare an N 30 binder from the waste material of the mine bioleaching process by heat treatment and to use the prepared binder to cure the same N or different waste fraction from the same bioleaching process. The binder may be made of S effluent, sludge, sludge or sludge, and N may cure effluent, sludge, sludge, sludge or N 35 other waste fraction or material containing water and solid particles.

The idea of one embodiment is to produce a curable binder from one of the following waste materials: pre-neutralization alite, final neutralization alite (LoNe), metal recovery alite (iron sludge, 5 RaSa) or mine water treatment alite. 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 in this document in a 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, N making it significantly easier and safer to handle and store than liquid or non-liquid? material.

The idea of one embodiment is to use a curable mixture as the building material of the structure in the mine area, whereby the formed structure is at the same time the disposal site of the waste material.

The idea of one embodiment is to form a rigid and independent structure rising upwards from the cured waste material or to cure the waste material into such an upwardly rising structure by means of a binder. According to an embodiment of Fra, the above-mentioned structure is one of the following: a pile, a convexity, a bulge, a hill, an artificial rock, a rampart, a protective wall, a wall or a 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 one embodiment, the structure comprises vertical or steeply inclined surfaces. According to the embodiment, the height difference between the uppermost part of the structure and the surface surrounding the structure is at least 10 m.

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

- S According to one embodiment, the maximum height N of the structure with respect to the surrounding surface is at least 40 meters. <Q According to the embodiment, the maximum height of the structure N 30 with respect to the surrounding surface is at least 50 meters. E According to the embodiment, the maximum height N of the structure with respect to the surrounding surface is at least 60 meters. S According to the embodiment, the maximum height N of the structure with respect to the surrounding surface is 70 to 120 meters. N 35 According to one embodiment, the floor area of the structure is less than 1 hectare.

According to one embodiment, the floor area of the structure is 1 hectare or more.

According to one embodiment, the structure is cast from a curable waste material as a mold cast, a slip cast or a 3-D cast.

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, for example, as a substitute for a surface layer of 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 N 30 roads leading to the mining area and other nearby roads.

E According to one embodiment, the curable N 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 substitute material can also be used in road construction

outside the mining area, for example in the maintenance, renovation and construction of roads leading to the mining area and other nearby roads.

According to one embodiment, a curable 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. N Such solid material can be temporarily stored in a suitable place near an object to be further landscaped. When the covering time later arrives, N 30 can be formed from this intermediate stored material into an covering layer E, for example on top of gypsum sediment basins, side rock piles, concentrate sand piles and other by-product warehouses and disposal sites N in the mining area. Because the cover material is solid and has mechanical strength, it can also be easily formed into desired surface shapes during landscaping. The material can be, for example, crushed stone of the desired size, which can be used to form the desired ditches and sloping surfaces in the cover layer to control 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 machine and transport. The idea of one embodiment is that E of the waste material formed in the above-mentioned processes and situations can be simply and S cost-effectively converted into a compressible building, filling and covering material suitable for construction.

OF

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 curable binder which can be used as a binder in the curing of other materials suitable for civil engineering. Binder-curable 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 (CH).

N According to one embodiment, the solution presented in this document P treats an alkaline gypsum-based precipitate E formed in the treatment of metallic water N 30, which has precipitated at the bottom of the gypsum basin. In the gypsum precipitation basin, the solid in the precipitate, 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 35, typically 80-85%.

According to the embodiment, the gypsum precipitate is transferred to the disposal area by pumping along the discharge pipe. During the transfer, the reactive curable binder disclosed herein is mixed with the gypsum precipitate to cure the gypsum deposit 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.

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

S OF

According to one embodiment, the curable material or cured material or structure disclosed herein has a compressive strength of at least 0.5 MPa.

According to one embodiment, the curable material or cured material or structure disclosed herein has a compressive strength of at least 1 MPa.

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 disclosed herein or the material or structure cured therewith has a compressive strength of at least 10 MPa. P The idea of one embodiment is that waste heat and energy generated in N production facilities in or near the mining area can be used for both heat drying and actual heat treatment. S It is still possible to use electricity generated by wind energy for heating, as well as solar energy as such

N targeted by means of lenses, converted into electricity by means of solar cells or by means of heat produced by various other solar collectors.

Heating and activation The following are some observations from the experiments performed and the phenomena that have occurred or are suspected in them. 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 ferrous sulfate-containing material, it has been found in experiments that a suitable heating temperature is 100 to 180 ° C. A suitable heating temperature has also been found to depend on the amount of impurities in the starting material. By increasing the temperature, it has been found that N can shorten the processing time. On the other hand, by extending the N treatment time, the heat treatment can be performed at a lower temperature. J 30 Experiments have shown that it makes sense to apply heating to a thin material thickness so that it has a large area N 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 N35.

As an alternative to the surface heating described above, the material can be mixed during heating. In this case, the material is exposed to the oxidizing 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.

An alternative heat treatment technique is a bubble fluidized bed, circulating fluidized bed, and fluidization method 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.

S LÖ Increasing the dry matter content <Q The idea of an embodiment is to increase the dry matter content of the waste water, sludge or precipitate before heat treatment. In this way, an attempt is made to increase the metal content, calcium sulphate content or both of the waste material N before heating. In addition, the actual heat treatment time can be shortened if the starting material N 35 is well pre-dried.

The following techniques and devices, as well as combinations thereof, can be used to increase the dry matter content and dewatering of the waste material: - Mechanical dewatering or drying, for example by centrifugation, whereby water is removed from the solid by centrifugal force.

- 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.

N - Drying can also be done using geotubes or N geotags. In this case, the substance to be treated is placed inside the tube or bag and the liquid N30 is gradually removed and the solid remains. E - Water separation can also be done with ultrasound N. By applying ultrasound to the slurry or S precipitate, water and solids are separated. N - Heating and drying N 35 may be preceded by an increase in solids content by some acoustic technique. This could be, for example, an acoustic resonance pool. Acoustic resonance can also be utilized below ultrasonic frequencies. - In precipitation, the solid 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 settling basin, from where it can be pumped to a 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 N In the experiments performed, the solid reacted by heat treatment N was ground to a fine <Q powder. In experiments, 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 particles of the fine powder have a large reaction area and efficient mixing in the mixture.

Bond Formation In the experiments performed, it was found that the material or powder reacted as described above reacted with water to form a strong bond when dried. When the material processed to be reactive was subsequently mixed with water or another solution containing one or more hydroxides, 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, S has significant logistical and economic benefits.

LÖ P Use of reactive material N 30 Reactive material prepared from mine metal sulphate-containing effluent, E sludge, sludge or clay waste material can be used in the mine and mining area in a number of N ways. In other words, in the way described in this document, N 35 is difficult to handle and harmful to the environment.

the neosa can be converted to a less hazardous form and the waste material can even be converted into a useful building material for the construction of mine roads, tailings ponds, dams, storage site foundations and other infrastructure.

According to one embodiment, the waste material 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 on the objects to be covered. If necessary, the machining and hardening properties N of the mixture thus prepared E can be adjusted by adding to the alloying elements slaked S lime Ca (OH), gypsum CaSO; or quicklime CaO. N The reactive material causing the curing can be mixed by means of a wastewater mixing device, for example during or in connection with transfer pumping.

The agitator equipment can be adapted as an extension of or in connection with the discharge pipe of the settling tank.

It is also possible to pump wastewater or the like from a settling tank to a tank truck, mix the reactive binder with the effluent to be transported, transport the cargo to the unloading coverage area and 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 premises required by the excavation method to strengthen their LÖ structure.

If necessary, the machining and hardening properties of the P mixture thus prepared can be adjusted by adding N 30 slaked lime E Ca (OH), gypsum CaSO, or quicklime CaO to the mixture.

Paste filling can also be used in situations where it is necessary to fix the rock next to the object to be excavated before starting excavation.

N 35 The method of filling said pasta can be a composite filling, which utilizes both the extracted side rock and the curable binder made from the sludge from the bioleaching process.

The use of the curable material disclosed in this application as a binder for the pasta filler is preferred because it can be cured very rapidly.

This avoids long waiting times and excavation can be resumed next to the filled cavity or space only 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 processing 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 slip casting and 3-D printing are suitable, for example, for the construction of N edge walls of precipitation and water treatment tanks.

Sliding casting and printing techniques can also be used in the installation of cover structures, so that it is possible to produce large uniform protective structures which are well protected e.g. rainwater.

A support structure can be provided on top of the Kip-E sink basin or the like, from which a deck structure can be cast.

S Alternatively, a lightweight mobile casting system can be used to cast on the pool, for example by injection molding or conveyors.

Some examples of experiments carried out Example 1: 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 presumed iron sulfate Fe, SO 5. The slurry was heated in an oven at 180? C at which time the water was first evaporated off. 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.

N In a similar manner, the powder was used to harden the precipitate taken from the bottom of the gypsum sediment basin. <Q It was found that already after a curing time N 30 of half an hour, the compressive strength of the cured mass was about 10 MPa. E The compressive strength did not increase significantly from this value as the hardening time was extended. S In one experiment, a N-sulphate-containing waste sludge from a gypsum sludge basin was prepared by first removing water from N 35 and then heat treating the reactive binder.

netta. When 1/3 by volume of this prepared binder and 2/3 of the corresponding metal sulphate-containing waste sludge from the gypsum sludge basin were taken and mixed with them in said mixture ratio, the mixture was made to harden to a compressive strength of 10 MPa. Thus, in the experiment, the waste sludge was first made into a binder and then the same waste sludge was cured with a 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-S were measured from the waste sludge (solids content 15-65% wet weight and pH LÖ ranged from 5.0 to 9.0). The waste slurry (precipitate) was mixed with a whisk until dried and dried and heat-treated at 105 ° C (1 E day) in the presence of an oxygen-containing gas mixture. The dried N solid was triturated and homogenized to a powder. In this way S was obtained with a binder powder which was activated with water and waste sludge. N 35 The experiment was repeated at various temperatures between 30 and 245 ° C and it was found that the required treatment time depends on the temperature used. The binder properties of the powder also become less favorable if the treatment is carried out at a temperature below 80 ° C or above 200 ° C. Example 4 A binder powder 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 consolidation. 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 repeating the test 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 intensity of vibration, powder-water ratio, temperature of the alloys (0 ° C to 60 ° C). and depending on the homogeneity of the mixture. Compressive strength results from 28-day-old prism test specimens have been measured to be in the range of 0.5 to 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.

3 N Example 5 N 35 A curable powder from waste sludge was also prepared from a slurry that was almost or completely clay-like (i.e., larger than the waste sludge sample).

Concentration, i.e. increasing the solids content, was carried out by gravity and pressure filtration.

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 to a homogeneous powder mechanically, and the powder thus prepared had similar hardening and machining properties as the thermal drying and heat treatment alone mentioned above.

Example 6 A solid was prepared from a powder prepared from a sample batch of 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). N When the test was repeated with the same powder from the same batch of slurry and the same powder-to-slurry ratio P, the workability time varied from 1 to 10 minutes. depending on the homogeneity of the mixture. 3 When repeating the experiment with powders prepared from different batches of waste sludge N and untreated waste sludge N 35, the processing time varied from 30 seconds to 60 minutes depending on the vibration intensity, powder-to-sludge ratio, sludge solids content, 60 ° C to 0 ° 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 5 MPa depending on the recipe.

The workability time and final strength 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 to the powder a concentrated sludge (in clay form) with 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.

N When repeating the experiment with powders prepared from different batches of waste sludge N and with concentrated waste sludge P, the processing time varied between 30 seconds and 60 N 30 minutes depending on the vibration intensity, powder-waste sludge ratio, sludge solids content, N mixture temperatures (0 ° 99 ° C) and depending on the homogeneity of the mixture S.

Compressive strength results from 28-day-old N prism specimens have been measured to be between N 35 0.5 and 5 MPa depending on the recipe.

The workability time and final strength were found to depend on the chemical composition of the waste sludge sample added to the powder and the solids content of the concentrated waste sludge.

Example 8 When testing the binder properties of a heat-treated powder prepared from waste sludge in soil stabilization, it was found that dredging spoils, peat, silt, clays, crushed stone and gravel, among others, are stabilized in the same manner 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 from the waste incineration plant are also stabilized.

Example 11 In a freeze-thaw test, it was found that the duration of the test prepared from the binder powder and water N prepared from the waste slurry was 12 freeze-thaw cycles before the body crumbled. <Q N 30 E Definitions of relevant terms N Of the terms used in this document, the following should be mentioned: N - Wastewater is disused N 35 water with a harmful amount of foreign matter.

neita. In this application, waste water refers in particular to industrial waste water and mining water. In mining, water is used in mining, ore grinding and enrichment, and possible further processing. Mining water includes process water circulating in mining processes, 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 (Dbioleaching) 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.

N Bioleaching can be bioheap leaching, but the proposed solution is of course suitable for use in other mines utilizing bioleaching processes. N 30 In bioheap leaching, favorable conditions for the activity of E bacteria are created in the leach heaps by wetting N 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 N by means of irrigation tubes so that the bacterial activity N35 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.

The main processes in the production process are: mining, crushing, agglomeration, bioheap leaching and metal recovery.

After agglomeration, the ore is piled into heaps 6-12 meters high, where it is dissolved for 1-3 years. 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 (HSO 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: N Metal sulphate (MeSO) + lime milk (Ca (OH) 2) + N Gypsum precipitate (CaSO: x HO) + metal hydroxide Me (CH) o N 30 metal-containing effluents, effluents and fines.

3

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The above embodiments and the features set forth therein may be combined to provide the desired solutions. BRIEF DESCRIPTION OF THE DRAWINGS Some embodiments of the present solution are shown in more detail in the following figures, in which Figure 1 is a schematic and simplified diagram of an arrangement for treating waste material from bioleaching; Figure 2 is a schematic and simplified diagram of a Fig. 4 schematically shows some structures and applications made of curable material in the mining area, Fig. 5 schematically shows a deck structure formed of curable material on top of a basin, for mixing the binder and wherein the waste material is introduced into the pool to harden after further addition; and Figure 7 is a schematic and side view of a very tall structure in which a 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.

= 30 In the figures, the same reference numerals are used to refer to the same elements and features.

S S DETAILED DESCRIPTION OF SOME EMBODIMENTS S Figure 1 shows the steps for converting wet waste material from bioleaching to a binder and how the prepared binder can be utilized in a mining area. The waste material 1 can be pretreated 2 to increase its 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 a heat treatment 3. In the heat treatment, the waste material is heated in an oven or similar heating device. After heating and activation, the cured material can be ground into 4 fine powders. The prepared powder can be used as a binder 5, which can be used to cure 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 N sulphate 12 to N reacting and strengthening with water or other hydroxides. During heating <Q, one or more other reactions can take place which N 30 causes or promotes the formation of the reactive curable substance 13. In any case, practical experiments have shown that the waste material formed in bioleaching can be prepared by heat treatment with water or N other hydroxides. reactive and reinforcing substance N 35 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 for curing 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. Figure 4 shows some applications.

The curable material can be made into a embankment 17 or a rampart, which can be used, for example, as a pool edge or a protective structure.

If necessary, the machining and strength properties can be adjusted by additional material, for example gypsum CaSO1, slaked lime Ca (OH), or slaked lime 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 disclosed curable material can also be used as a coating for the mine and its surroundings on roads and fields 21 and as a surface layer. It can also be seen from Figure 4 that the upwardly extending structures 17, 18 and 19 can be formed directly on the E-planar surface 22.

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

At the edges of the basin 23 there are embankments N 17, which may be formed of the curable material N 35 shown.

The final covering of the basin 23 can be done by casting a lid 24 of curable material on it.

Fig. 6 shows an arrangement in which a mixing apparatus 27 is arranged in the discharge pipe 26 of the effluent or similar waste material of the unit 25 for the bioleaching process or metal recovery. The waste material can be discharged to 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 material and transported for use in or near the mining area as a soil or paving 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 N structure compared to current dumps. N 30 The sides of the structure can be staggered 32 taking into account occupational safety and disposal technology. In the case of final disposal, soil, bentonite, various films, nets, creams and geotextiles may be applied to the structure, which may be involved in landscaping, anti-weathering, water management or other matters. These above-mentioned materials and components can be combined as desired to form a suitable cover layer 33. The step 32 mentioned above can also participate in and facilitate the installation and retention of the cover layer.

It should be noted that in Figure 7 the relationships of the dimensions of the structure to each other are not necessarily to scale.

The figures and their description are only intended 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)

Claims A method of treating waste material, the method comprising treating waste material generated in a mine bioleaching process as wastewater, sludge or sludge and heating the waste material to convert it into a reactive reinforcing agent. characterized in that a binder for the waste material of the mine bioleaching process is produced by heat treatment and the prepared binder is used for curing the same or different waste fractions from the same bioleaching process. Process according to Claim 1, characterized in that the waste material is converted into a reactive substance by heating alone 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 continuing the heat treatment after drying to activate the dried waste material to a reactive reinforcing material. OF LO P Process according to one of the preceding claims 1 to 3, characterized in that E is a heat-treated metal sulphate-containing waste material so that the metal sulphate compounds contained therein are activated to react with water and hydroxides as well as to strengthen. N 35 Method according to one of the preceding claims 1 to 4, characterized in that the metal sulphate-containing waste material is heated to 30 to 300 μm. C and under the influence of oxygen. Process according to one of the preceding claims 1 to 5, characterized in that the waste material containing metal sulphates and calcium sulphate CaSO is treated, the calcium sulphate being converted on heating to anhydrite, which is a curable material. Process according to one of the preceding claims 1 to 6, characterized in that, after the heat treatment, the solid activated by the heat treatment is ground to a fine powder suitable for use as a reinforcing binder. Process according to any one of the preceding claims 1 to 7, characterized in that the slurry from the treatment of the effluent from the mine's bioleaching process is treated by mixing with a binder prepared according to any one of claims 1 to 7, the binder curing at least to a hardness of 500 kPa. S LÖ 9. Arrangement for the disposal of waste material <Q in a mining area, J 30 characterized in that E is made from a waste material formed in the mine's bioleaching process, which is wastewater, sludge S or a slurry, a binder which is made by reactive heating N into a reactive curing agent; N 35 mixes the binder with the waste material to be disposed of; and disposing of the mine waste material as a cured structure or material in the mining area; and wherein said waste material to be disposed of is the same waste material generated in the mine bioleaching process from which said curable binder is made. Arrangement according to Claim 9, characterized in that a curable mixture is used as the building material of the structure in the mining area, the structure formed being at the same time the final disposal site for the waste material. Arrangement according to Claim 9 or 10, characterized in that a rigid and independent structure rising from the curable waste material is formed. Arrangement according to one of the preceding claims 9 to 11, characterized in that a curable waste material is used as the earthworks in the mining area. 13. Reinforcing binder made from waste material; characterized in that the N binder is prepared from a metal sulphate-P-containing substrate or filtrate cake formed in the wastewater treatment of a mine bioleaching process by heating the material to a reactive form and which binder is intended for curing N waste material from the same bioleaching process. 3 N Binder according to Claim 13, characterized in that the treated material is ground after heating, the binder being in powder form. Binder according to Claim 13 or 14, characterized in that the binder is adapted to react with water or another liquid of the OH group when stirred and to cause a hardening reaction. OF O OF O <Q + OF I Jami a N + O O O OF O OF