WO2017061884A1

WO2017061884A1 - Method of manufacturing basalt powder, basalt fibers and other shaped products

Info

Publication number: WO2017061884A1
Application number: PCT/PL2016/000114
Authority: WO
Inventors: Marek Majcher
Original assignee: Przedsiebiorstwo Budowlano-Montazowe Flisbud Stanislaw Flis
Current assignee: Przedsiebiorstwo Budowlano-Montazowe Flisbud Stanislaw Flis
Priority date: 2015-10-09
Filing date: 2016-10-07
Publication date: 2017-04-13
Anticipated expiration: 2018-04-09
Also published as: PL414330A1

Abstract

The present invention relates to the method of manufacturing basalt powder, basalt fibers and other shaped products, comprising grinding the raw material of basalt and optionally melting the basalt by heating it to a temperature in the range of 1450°C to 1550°C, characterized in that, the raw material of basalt is crushed to obtain a particle size of less than 5 mm, preferably in the range of from 1 to 3 mm, then, the thus obtained powdery raw material is combined with water in a ratio of 5 to 50 liters of water per 100 g of basalt, and obtained suspension is homogenized, processed through further fragmentation and purification in the reaction chamber equipped with electric pulse generator, wherein the water and basalt powder suspension is simultaneously electrolyzed within the same chamber, equipped with at least one carbon based electrode, on which retain basalt impurities, then solid particles of basalt are separated from the water and dried under anaerobic conditions, and then optionally melted in a temperature in the range of 1450°C to 1550°C and optionally basalt fibers, or other shaped products are prepared.

Description

Method of manufacturing basalt powder, basalt fibers and other shaped products

The present invention relates to a method of manufacturing basalt powder, basalt fibers and other shaped products by melting basalt powder at high temperature to produce malleable basaltic magma.

The molten basalt rock has many applications as it is possible to produce basalt fibers or threads from it. Basalt fibers can be produced through different technologies and the obtained products possess various properties. Produced fibers may have a diameter from a few to tens of micrometers, and different applications. Basalt fibers, pure or in combination with other additives are used as raw materials for the production of insulating materials for constructions (i.e. wool available as Rockwooi), or for the manufacture of prefabricated elements reinforced by short (discontinuous) basalt fibers, which play the similar role as glass fibers. Reinforcement mats or bars with addition of multicore basalt thread are also produced and dedicated for the constructions sector.

Yarns and basalt fibers are also used for materials weaving, in particular, protective and temperature resistant materials. In the fabric (textile) a basalt thread may be a filament (roving) surrounded by segmental yarn from aramid, polyamide or polypropylene epoxidized vegetable oils, or polypropylene or the fabric can be completely woven using only basalt threads. It is also possible to twist multiple filaments of basalt to produce a stronger fabrics/mats, which further constitute the matrix for hardenable resins like epoxy, vinyl or polyester resins.

Basalt nonwoven fabrics may also be used for production of various kinds of filters, especially when the filters must operate at high temperatures.

In the process of the basalt yarn production, basalt is pre-treated, grinded and annealed, and then it is melted at high temperature until liquid state at approx. 1500°C. Various techniques are then applied to produce basalt filaments, fibers or yarns, usually having a diameter of from 10 to 22 am. General information about the use and properties of basalt fibers, can be, for example, found in the on-line available publication "Basalt fibers as reinforcement for composites," Van de Velde K., Kiekens P., Van LANGENHOVE L, Department of Textiles, Ghent University, Technologiepark 907, B -9052 Zwijnaarde, Belgium. In this publication, among other information, we can find a typical composition of basalt raw materials used to manufacture basalt threads. Namely, it contains (in percent by weight) S1O2 in an amount of 51.6 - 57.5, AI2O3 in an amount of 16.9 - 18.2, CaO in an amount of 5.2 - 7.8, MgO in an amount of 1 .3 - 3.7, Na₂0 in an amount of 2.5 - 6.4, K₂0 in an amount of 0.8 - 4.5 and Fe₂0₃ in an amount of 4.0 - 9.5.

Compared to glass fiber, basalt fiber has a relatively large content of iron and phosphorus compounds.

From the patent application KR200200816 3A, there is known a production plant for manufacturing basalt fiber used in the sound-absorbing and heat- resistant mats. For the preparation of fibers, grinded basalt with a particle size of 3-10 mm is used as the feedstock. Basalt is then melted at a temperature of 1450-1550°C.

Technologies of manufacturing basalt fibers are also known from the descriptions of patent applications EP0583792A1 , EP0525816A1 , EP0957068A1 and US5352260A.

The object of the present invention is the method of manufacturing basalt powder, basalt fibers and other shaped products, comprising grinding the raw material of basalt and optionally melting the basalt by heating it to a temperature in the range of 1450°C to 1550°C, characterized in that, the raw material of basalt is crushed to obtain a particle size of less than 5 mm, preferably in the range of from 1 to 3 mm, then, the thus obtained powdery raw material is combined with water in a ratio of 5 to 50 liters of water per 100 g of basalt, and obtained suspension is homogenized, processed through further fragmentation and purification in the reaction chamber equipped with electric pulse generator, wherein the water and basalt powder suspension is simultaneously electrolyzed within the same chamber, equipped with at least one carbon based electrode, on which retain basalt impurities, then solid particles of basalt are separated from the water and dried under anaerobic conditions, and then optionally melted in a temperature in the range of 1450°C to 1550°C and optionally basalt fibers, or other shaped products are prepared.

Solid basalt particles are separated from the water by filtration or centrifugation, and basalt particles separated from water are dried at a temperature in the range of 300 to 400°C. Dried basalt particles have a very small size, that at least 50% by weight of the particles have the size below 200μιη. At the same time, dried basalt particles have a content of not more than 1 ppm of iron compounds. The basalt particles are purified by removing 99.9% of the impurities of iron, manganese and phosphorus compounds.

The object of the present invention is also using the basalt powder, obtained by the defined above method of preparation of basalt fibers in 3D printing. The method, according to the invention, makes basalt fibers production process more economical and reduces energy consumption. Conventional methods of basalt fiber production include additional initial basalt ignition step at even 900°C, which demands huge amounts of energy. The method, according to the invention, enables purification of basalt grains (basalt powder) from detrimental impurities, such as iron compounds, usually present in a form of oxides or phosphorus compounds present as phosphates. In the last stage of the method of producing basalt fibers, these impurities have negative impact on the properties of produced basalt fibers. Also, the impurities force long lasting heating until the basaltic magma processing is stable to enable to draw the fiber.

Due to the significant fragmentation of the basalt raw material by ultrasounds generated by electric pulses and other occurring sonic processes, it is possible to eliminate aforementioned contaminants from the aqueous suspension more effectively.

The term "basalt fiber" for the purpose of this invention should be understood broadly, i.e. it includes or is synonymous with other terms such as the basalt thread, basalt yarn, basalt silk, etc. Grinding of the basalt may be carried out by various known methods, e.g. it may be performed by conical grinding mills, ball mills or electromagnetic mills and other mills, which are adapted to grinding hard minerals. Preferably, in the method according to the invention, obtained basalt grains size after the grinding process is less than 5 mm, e.g. of 1 to 3 mm. For a person skilled in the art, it will become apparent at this stage of the process, to use sieves with determined mesh sizes and assure the ability to return the bulk of the raw materia! to be milled again, depending on the needs.

The water used in the process._^ according to the invention, is preferably ordinary industrial water, which was not subjected to any special treatment. Preferred is the use of chlorinated water, which supports processes occurring in aqueous suspension between the basalt particles, and the water treated by ultrasounds, and in the course of electrolysis.

In the present invention, a large excess of water in relation to the basalt is used and it varies from 5 to 50 liters of water per 100 grams of basalt, in particular from 20 to 50 liters of water per 100 grams of basalt, wherein, for the low iron content basalt, water proportion falls the bottom limit of the indicated range. For basalts with the highest contents of iron (approx. 9- 10%), proportion of water in the treated suspension should be the highest, not lower than 5 liters per 1 gram of bounded iron present in the basalt rock. Before the implementation of the method according to the invention, the actual content of iron compounds in the sample of treated basalt is determined in a laboratory. Depending on the results, lower or higher amount of water is supplied.

Dry raw material feed and water feed to the reaction chamber is performed periodically to allow saturation of the water with compounds passing from the solid phase to the aqueous phase, while the suspension is exposed to electrical pulses, and to allow the separation of impurities from the aqueous phase to the graphite electrodes.

Production of basalt fibers in the last step of the process according to the invention, can be performed by any known method which is suitable for spinning of mineral fibers such as basalt fibers. For example, it can be carried out using the spinner, wherein the molten mineral material is spread on the wall of the spinner, wherein the spinner has numerous nozzles with small diameter. The nozzles are used for centrifuging of mineral material at appropriately high temperature. Fibers can be drawn up directing the stream of gas along the wall of the spinner. The nozzles of the spinner can have diameters from 0.1 to 0.7 mm, which allows production of fibers adapted to the needs of a diverse diameter.

The molten basalt powder can be used to produce other shapes such as rods or sheets, which are produced in the glass technology, the flotation method may be particularly useful there. Due to some analogies in the processes of basalt and glass processing, we can apply similar methods for the production of basalt shapes i.e. heat treatment (melting dry mineral ingredients).

The purified basalt powder obtained through the process according to the invention, can be used for production of basalt fibers "in situ" in 3D printers as a fiber used for forming the desired end product. Dry powder basalt fills the developer cartridge in the printer. During operation, basalt powder is heated to the desired temperature in the range 1450-1550°C to form basalt yarn.

In the method according to the present invention, the aqueous basalt suspension was sonicated with use of the pulse generator, as the source of the ultrasounds, which assures further fragmentation of basalt grains. Under the effect of pulses, also some physico-chemical and sonochemical phenomenon occur on the edge of the water-mineral grains phase.

The use of electro burst activation technology allows impurities to be separated from basalt grains. The method is energy-efficient, versatile and can be applied to the raw material of various origin, without any pre- treatment.

The reaction chamber, in which the method according to the invention is carried out, is equipped with a pulse generator. The generator voltage to the discharge is delivered in a form of short pulses with a duration of a few micro- to milliseconds. The excitation and ionization phenomena, which both non-linear!y depend on the electric field, are much more intense, in the case of the pulse generator than other plasma technologies. Phenomenon which occur during impulse discharge should be treated as short-term DC discharge, followed by a long period of time without unloading (hereinafter called afterglow), until the next voltage pulse. The short-duration voltage pulse energies of electrons reach much higher values (at a few eV level), than the energy of other plasma particles (less than 0.1 eV). As a result, generated plasma is already chemically active at lower energy level supplied from the power source, than it does with the DC. it is possible to use the power pulse discharge powered by 2 kV voltage, a pulse width of about 10 ps and a repetition rate of 200 Hz - all these factors result in up to 1 A and 2 kW electrical impulses. Discharge impulse reactor operates at pressures of 100 Pa, voltage pulses with a peak value of 500 V and a running time of 100 microseconds. The geometrical dimensions of this type of reactor can be relatively large and have a few cubic meters (see Henryka Danuta Stryczewska, Plasma technologies in the energy and environmental engineering, Publishing University of Lublin, Lublin 2009).

For the purposes of the invention, a reaction chamber with a capacity to process 350 kg of basalt material per hour has been applied. The process is a continuous process. Grinded and purified basalt (basalt micro particles) gravitationally settles down on the bottom part of the reaction chamber and is collected in this place. Basalt raw material feed preferably is carried out from the top of the chamber. The ultrasounds generator is placed on the bottom of the reaction chamber, where the suspension density is high. Electrodes, which retain impurities are placed in the top part of the reaction chamber, where the suspension has a lower density and a higher proportion of water.

Basalt suspension temperature raises, when it is treated by the impulses, and due to the occurring physicochemical processes, water can partially evaporate, and formed in this way gases are then continuously removed from the reactor.

Due to the energy supplied to the reactor equipped with a pulse generator, between the particles the high-temperature plasma discharges occur and as a result shock waves and cavitation effect with electromagnetic radiation and ultraviolet (UV) light emission are observed. The above described phenomenon cause separation of any impurities from basalt within the area of electrical discharge points and impurities in form of micron particles are dispersed into the water. Due to the presence of large amounts of silicon bounded in the basalt powder, which is advantageous in this type of treatment processes, cavitation process produces a dispersion of micron liquid silicon drops in water, which also supports the impurities separation process.

The basalt grains suspension in water is treated by electric impulses in the reaction chamber, that simultaneously cause the electrolysis and settlement of the basalt contaminants on the electrodes based on carbon.

Thus, two processes run simultaneously - grinding grains in the suspension and the release of contaminants from basalt grains to the aqueous phase and the electrolytic settlement of, for example, compounds of iron, manganese and other impurities on the electrodes based on carbon, e.g. porous titanium-carbon electrode (cathode). Applied term "carbon (graphite) based electrode" indicates different types of electrodes containing graphite and optionally other ingredients.

Simultaneously, the gases from anions destruction (anions appear in the suspension) can be emitted from the suspension. At this stage, not desired components of basalt are separated, which allows to obtain suspension of micro- and nanoparticles of purified basalt, in which 99.9% by weight of any impurities (compounds of iron, phosphorus, manganese) have been eliminated.

The reactor is equipped with at least one graphite based electrode, preferably with two, three or four electrodes e.g. titanium-graphite electrodes. The reactor housing acts as an opposite electrode - the anode. Graphite/carbon based electrodes operate on 1 to 3.5 ampere current and the voltage at 500 to 1200 volts. Graphite-based electrodes act periodically in the process and are replaced once worn out.

Purified basalt is subjected to filtration or centrifugation, then is dried and calcined at 300-400°C, preferably 350°C in a vacuum furnace in anaerobic conditions; for example, in environment of nitrogen or carbon dioxide. This step of drying the basalt powder may take 15 minutes to 2 hours; for example, 30 minutes or 1 hour.

According to the invention, it is possible to end the process at this stage. Obtained powdered basalt raw material (preform) can be packaged using any available vacuum method, preferably method performed without oxygen.

The basalt powder can be further used in goods thermoforming, or as paints, varnishes, protective coatings additive.

By method according to the invention, we have obtained basalt, which needs 3 times shorter residence time in the basaltic magma melting chamber and is purified from iron, phosphates and other pollutants.

The method of the invention may also comprise further stages of basalt powder processing e.g. melting it to obtain basaltic magma and then forming products such as fibers or profiles, shaped and molded products, construction elements.

According to the invention, the process energy demand for the method carried out until the final shaped products such as basalt fiber is between 8 to 10 kWh per 1 kg of basalt. Basalt magma is obtained in a standard temp, approx. 1500°C, however, required heating time may be reduced to 1 -2 hours, or about one hour.

Obtained purified basalt powder particles have powdered (micronized) micron size below 20Όμίη, and below 100μΐη and even below 10 μιη e.g. 50% of the particles of obtained powder are basalt nanoparticles having size less than 200μίτι or even 90% of the particles of obtained powder have size below 200μΓη.

When basaltic magma is used to produce molded products, the magma temperature is then maintained within its area of operation. Thermal forming facilities can produce various molded products, fittings, shapes, for example: rods, granules, threads, plates, spheres, shapes like channel section, C- profiles, T-profiles etc. Obtained through the applied method according to the invention, processed and purified basalt grains are also subject for further heat treatment and/or chemical treatment in the anti-corrosion protecting means production process, e.g. paints and varnishes, which, due to their properties are the best among all the currently used anti-corrosion agents. Basalt anticorrosive coatings are resistant to all aggressive factors including alkalis and acids, except hydrofluoric acid or hydro-acidic acids, which do not contain oxygen. Such coatings can also be used as fire protection, sound and thermal insulation as well as fire resistant cable sheaths and other.

Example 1

Basalt with a high iron compounds content (9% wt.) was grinded in a cone mill to obtain particles with size of 1-3 mm. Grinded material in a powder form is a reactor feed in, the reactor is equipped with electrical impulses reactor wherein the impulse discharges need to be supplied with voltage of 2 kV, a pulse width of about 10 microseconds and a repetition rate of 200 Hz. Quoted parameters allow to generate impulses up to 1 A and respectively up to 2 kW.

The basalt powder purification process was carried out in presence of water using a ratio of 5 I of water per 10 grams of basalt grains. The reactor was equipped with three titanium and graphite electrodes. The process was conducted in 1 hour, the 350 kg of basalt were treated in this time and 99.9% by weight of impurities (iron, manganese and phosphorus) of obtained product were removed.

Basalt powder was separated from the water using filtration method, obtained paste was dried in nitrogen environment at 350°C for 1 hour. Above 60% of obtained dry basalt particles had size below 200μίη. Dry basa!t powder was vacuum packed in plastic bags.

Example 2

The dry powder obtained according to example 1 was melted at 1450- 1550°C and processed for 1 hour in a spinner dedicated for mineral fibers manufacture. The basalt yarn have been manufactured.

Example 3 The process according to Example 1 was performed. Basalt powder with low content of iron (4% by weight) was processed. 2 liters of water per 10 grams of basalt grains were used in the process of making basalt water suspension. Obtained basalt powder has properties as described in example 1. The dried powder was stored with no air access and then used in a 3D printer as a cartridge filling calling, desired high hardness products were obtained.

Claims

1. A method of manufacturing basalt powder, basalt fibers and other shaped products, comprising grinding the raw material of basalt and optionally melting the basalt by heating it to a temperature in the range of 1450°C to 550°C, characterized in that, the raw material of basalt is crushed to obtain a particle size of less than 5 mm, preferably in the range of from 1 to 3 mm, then, the thus obtained powdery raw material is combined with water in a ratio of 5 to 50 liters of water per 100g of basalt, and obtained suspension is homogenized, processed through further fragmentation and purification in the reaction chamber equipped with electric pulse generator, wherein the water and basalt powder suspension is simultaneously electroiyzed within the same chamber, equipped with at least one carbon based electrode, on which retain basalt impurities, then solid particles of basalt are separated from the water and dried under anaerobic conditions, and then optionally melted in a temperature in the range of 1450°C to 1550°C and optionally basalt fibers, or other shaped products are prepared.

2. The method according to claim 1 , wherein the solid basalt particles are separated from the water by filtration or centrifugation.

3. The method of claim 1 or 2, wherein separated from water solid basalt particles are dried at a temperature in the range of 300 to 400°C.

4. The method of claim 3, wherein at least 50% by weight of dried basalt particles have a size below 200 pm.

5. The method of claim 3 or 4, wherein content of iron compounds in the dried basalt particles is up to 1 ppm.

6. The method according to any one of claims 1 to 5, wherein the basalt particles are purified by removing 99.9% of the impurities in the form of iron, manganese and phosphorus compounds.

7. Use of the basalt powder obtained by method according to claims 1 to 6, for basalt fibre production in 3D printers.