Method for preparing sodium silicate by using titanium-zirconium placer separation tailings and application thereof

Abstract

The present application relates to the technical field of ore dressing waste treatment, in particular to a method for preparing sodium silicate by using titanium-zirconium placer separation tailings and application thereof. The method for preparing sodium silicate by using titanium-zirconium placer separation tailings comprises: sequentially performing first grinding and first screening on the titanium-zirconium placer separation tailings to obtain first screen oversize and first screen undersize; obtaining first reselection tailings after first reselection of the first screen oversize; mixing the first reselection tailings with the first screen undersize and performing second grinding, and then performing second reselection to obtain second reselection tailings; mixing the second reselection tailings with soda ash and calcining to obtain sodium silicate crude product after cooling; obtaining sodium silicate solution after dissolution and solid-liquid separation of the sodium silicate crude product; heating and evaporating the sodium silicate solution to a saturated solution, and then performing temperature reduction crystallization to obtain sodium silicate. The method can obtain high-purity sodium silicate.

Description

Technical Field

[0001] This invention relates to the field of mineral processing waste treatment technology, and more specifically, to a method for preparing sodium silicate from tailings of titanium zirconium sand ore and its application. Background Technology

[0002] Coastal placer deposits are an important source of titanium and zirconium concentrates. Due to the influence of mineralization factors, titanium and zirconium are usually found as associated minerals in coastal placer deposits. The main mineral composition of titanium-zirconium placer deposits is ilmenite, rutile, zirconium silicate, and quartz. During mineral separation, magnetic separation is typically used to separate ilmenite to obtain titanium concentrate, while electrostatic-gravity separation is used to separate rutile and zirconium silicate to obtain natural rutile and zirconium concentrates. The remaining tailings are used as a waste byproduct for backfilling in mining sites or as inexpensive building materials. After repeated separation by magnetic, electrostatic, and gravity separation, titanium, zirconium, aluminum, calcium, and other elements are effectively separated. The tailings consist mainly of silica particles, primarily quartz, but some heavy mineral impurities may still remain.

[0003] Sodium silicate, a silicate containing various alkali metals and silicon dioxide, has a wide range of applications, including papermaking, soap making, leather making, casting, construction, refractory materials, and rubber. It can also be used as a raw material to prepare high-end materials such as silica gel, molecular sieves, dyes, and glass fibers, playing a vital role in the overall industrial sector. The preparation of sodium silicate requires a high silicon dioxide content and low impurity content. Separating tailings from titanium zirconium sand ore not only meets these production requirements but also increases economic value while treating mineral processing waste.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The primary objective of this invention is to provide a method for preparing sodium silicate from tailings of titanium zircon sand ore beneficiation. This method can obtain sodium silicate with high purity and low impurity content. Furthermore, this method reuses the tailings of titanium zircon sand ore beneficiation, thereby improving resource utilization and avoiding resource waste.

[0006] The second objective of this invention is to provide a method for preparing sodium silicate using tailings from titanium zirconium sand ore beneficiation, and to apply the sodium silicate obtained therefrom in papermaking, casting, titanium dioxide, soap, leather, construction, refractory materials, rubber, silica gel, molecular sieves, dyes, and glass fibers.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0008] This invention first provides a method for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation, comprising the following steps:

[0009] (a) The tailings of titanium zircon sand ore separation are subjected to a first grinding and a first screening to obtain a first screen oversize and a first screen undersize; the first screen oversize is subjected to a first gravity separation to obtain a first gravity separation tailings;

[0010] (b) The first gravity separation tailings are mixed with the first undersize material and then subjected to a second grinding.

[0011] Then a second separation is performed to obtain the tailings from the second separation.

[0012] (c) The tailings from the second gravity separation are mixed with soda ash and calcined, and then cooled to obtain crude sodium silicate.

[0013] (d) The crude sodium silicate is dissolved and separated into solid and liquid components to obtain a sodium silicate solution; the sodium silicate solution is heated and evaporated to a saturated solution, and then cooled and crystallized to obtain the sodium silicate.

[0014] This invention also provides the application of sodium silicate obtained by the method of preparing sodium silicate from titanium zircon sand tailings in papermaking, casting, titanium dioxide, soap, leather, construction, refractory materials, rubber, silica gel, molecular sieves, dyes and glass fibers;

[0015] Preferably, the purity of the sodium silicate is ≥93%, more preferably ≥98%.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] (1) The method for preparing sodium silicate using tailings of titanium zircon sand provided by the present invention purifies the quartz sand in the tailings of titanium zircon sand, and makes full use of the tailings of titanium zircon sand while meeting the sodium silicate production needs, thereby improving the economic value of the tailings of titanium zircon sand and increasing the resource utilization rate.

[0018] (2) The method for preparing sodium silicate using tailings from titanium zircon sand ore beneficiation provided by the present invention also has the advantages of simple process, low raw material cost and easy mass production.

[0019] (3) The method for preparing sodium silicate using tailings from titanium zircon sand ore beneficiation provided by the present invention can obtain high-purity, high-quality sodium silicate.

[0020] (4) The method for preparing sodium silicate using titanium zirconium sand tailings provided by the present invention, by controlling the mesh size of the screen used in the first screening, the proportion of the material on the first screen, and the proportion of the material on the screen with a mesh size of 160 or above in the second grinding, is beneficial to the subsequent high-temperature reaction and can ensure the yield of gravity separation. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 The present invention provides a process flow diagram for the preparation of sodium silicate from tailings of titanium zirconium sand ore. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0024] Unless otherwise specified, in this invention, terms such as "first aspect," "second aspect," "third aspect," and "fourth aspect" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, terms such as "first," "second," "third," and "fourth" serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0025] Unless otherwise specified, the terms "comprising" and "including" as used in this invention can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0026] Unless otherwise specified, in this invention, "one or more" or "at least one" refers to any one, any two, or any two or more of the listed items. "Several" refers to any two or more.

[0027] In a first aspect, the present invention provides a method for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation, see [link to previous article]. Figure 1 The diagram shows a process flow chart for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation, which includes the following steps:

[0028] (a) The tailings of titanium zircon sand ore are subjected to a first grinding and a first screening in sequence to obtain the first oversize and the first undersize. It can be understood that the oversize refers to the material that cannot pass through the screen and remains on the screen; the undersize refers to the material that can pass through the screen.

[0029] The material over the first screen is subjected to the first separation to obtain the first separation tailings.

[0030] It is understandable that the first-stage tailings were obtained along with the first-stage concentrate, which is a titanium-zirconium related heavy mineral, and it was used as waste for backfilling of the mining site.

[0031] (b) The first gravity separation tailings are mixed with the first screened material and then subjected to a second grinding, followed by a second gravity separation to obtain the second gravity separation tailings.

[0032] This application obtains a second gravity separation tailings with a smaller particle size through first and second grinding, which facilitates complete reaction with soda ash in the subsequent process.

[0033] Understandably, there is no need to sieve after the second grinding; instead, the second separation can be carried out directly.

[0034] Understandably, the second-stage tailings were obtained along with the second-stage concentrate, which is a titanium-zirconium related heavy mineral, and it was used as waste for backfilling of the mining site.

[0035] Sodium silicate has a wide range of applications, but the heavy titanium-zirconium ore impurities present in the tailings of titanium-zirconium sand ore beneficiation can affect its application. This invention removes most impurities through two grinding processes and two gravity separation processes. While removing the heavy ore impurities, the material is also ground finely, facilitating the preparation of sodium silicate.

[0036] (c) The second gravity separation tailings are mixed with soda ash and calcined, and then cooled to obtain crude sodium silicate.

[0037] Understandably, the main component of the tailings from the second separation process is quartz sand, in which SiO2 reacts with soda ash at high temperatures to produce sodium silicate and carbon dioxide.

[0038] (d) The crude sodium silicate is dissolved and separated into solid and liquid components to obtain a sodium silicate solution; wherein, dissolving and separating the crude sodium silicate can remove impurities.

[0039] Specifically, based on the principle that titanium dioxide and zirconium oxide are chemically stable and do not react with weak bases such as soda ash, the present invention dissolves and filters crude sodium silicate, which can further remove impurities entrained or residual in the crude sodium silicate, reduce the proportion of insoluble substances in the crude sodium silicate, and thus obtain high-purity, high-quality sodium silicate.

[0040] In some specific implementations, sodium silicate can be dissolved in water using any conventional method to form a sodium silicate solution.

[0041] The sodium silicate solution is heated and evaporated to form a saturated sodium silicate solution, which is then cooled and crystallized. The precipitated crystals are sodium silicate products with low impurity content.

[0042] The present invention provides a method for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation. By purifying the quartz sand in the tailings, this method fully utilizes the tailings while meeting sodium silicate production needs, thereby enhancing the economic value of the tailings and achieving maximum resource utilization. Furthermore, this method has advantages such as simple process, low raw material cost, and ease of mass production.

[0043] Specifically, grinding the titanium-zirconium sand tailings increases the degree of liberation between various phases. Since heavy mineral sands and quartz have a significant difference in specific gravity, gravity separation can remove heavy mineral sand impurities. Because grinding minerals can degrade the gravity separation effect, this application employs a two-step grinding and classification gravity separation method. The oversize particles obtained from the first grinding and screening are coarser and easier to gravity separate, while the undersize particles are finer and can be directly gravity separated with the minerals after the second grinding. This reduces the pressure on the first gravity separation, improves its efficiency, and minimizes interference with the first gravity separation, thus enhancing its separation effect. Through two gravity separations, the vast majority of heavy mineral sands in the tailings are removed. Two grinding processes transform the tailings sand into easily reactive high-purity silica powder (mainly composed of silicon dioxide). Furthermore, the combination of grinding and gravity separation enhances the separation effect of gravity separation.

[0044] Furthermore, soda ash is reacted with the obtained secondary gravity separation tailings at high temperature to obtain crude sodium silicate. The crude sodium silicate is then dissolved and filtered to remove some unreacted silica powder and unreacted impurities, thus purifying the sodium silicate. Finally, it is cooled and crystallized to obtain sodium silicate with low impurities and high purity.

[0045] In some specific embodiments, in step (a), the tailings of the titanium zircon sand ore sorting include the waste tailings obtained after separating titanium zircon sand ore from at least one of ilmenite, rutile and zirconium silicate.

[0046] In some specific embodiments, the tailings from the titanium-zirconium sand ore separation are the waste tailings generated after separating titanium-zirconium sand ore from ilmenite, rutile, and zirconium silicate.

[0047] In some specific implementations, in step (a), the main component of the titanium zircon sand tailings includes quartz.

[0048] In some specific embodiments, the tailings of the titanium-zirconium sand ore beneficiation also include heavy mineral sand impurities.

[0049] In some specific embodiments, the mass fraction of SiO2 in the tailings of the titanium zircon sand is ≥90%.

[0050] In some specific implementations, in step (a), the mesh size of the sieve used for the first screening is 150 to 200 mesh; including but not limited to the point value of any one of 150 mesh, 160 mesh, 170 mesh, 180 mesh, and 200 mesh, or the range between any two.

[0051] In some specific implementations, in step (a), the mass of the first screen oversize is 30% to 50% of the mass of the titanium zircon sand tailings, including but not limited to any one of 30%, 35%, 40%, 45%, and 50%, or any range between two of them.

[0052] By controlling the mesh size of the sieve used in the first screening and the proportion of the material on the first sieve within the above range, it is beneficial to the subsequent high-temperature reaction and can ensure the yield of gravity separation.

[0053] In some specific embodiments, in step (b), the percentage of the material mass of the sieve material with a mesh size of 160 or above in the second grinding process is 5 wt.% to 20 wt.%, including but not limited to any one of 5 wt.%, 8 wt.%, 10 wt.%, 13 wt.%, 15 wt.%, 18 wt.%, and 20 wt.%, or any range between two of them.

[0054] Understandably, no sieving is required after the second grinding, and all the material after the second grinding is reserved for subsequent use.

[0055] Specifically, after grinding for a period of time, the proportion of material with a mesh size of 160 or higher in the grinding material can be measured. Here, material with a mesh size of 160 or higher refers to the material remaining on the 160-mesh sieve (without leaking out).

[0056] By controlling the proportion of material on the sieve above 160 mesh in the second grinding process, it is beneficial to the subsequent high-temperature reaction and can ensure the yield of gravity separation.

[0057] In some specific implementations, the reselection equipment used in the first reselection in step (a) and the second reselection in step (b) is preferably a reselection shaker.

[0058] In some specific implementations, in step (a), the stroke of the first reselection is 15mm to 20mm, including but not limited to the point value of any one of 15mm, 16mm, 17mm, 18mm, 19mm, and 20mm or the range between any two; the stroke rate is 200 to 300 times / min, including but not limited to the point value of any one of 200 times / min, 220 times / min, 240 times / min, 250 times / min, 270 times / min, 290 times / min, and 300 times / min or the range between any two.

[0059] In some specific implementations, in step (b), the stroke of the second reselection is 10mm to 15mm, including but not limited to any one of 10mm, 11mm, 12mm, 13mm, 14mm, and 15mm or any range between two; the number of strokes is 250 to 350 times / min, including but not limited to any one of 250 times / min, 270 times / min, 290 times / min, 300 times / min, 320 times / min, 340 times / min, and 350 times / min or any range between two.

[0060] In some specific implementations, in step (a), the first grinding includes wet grinding.

[0061] In some specific implementations, in step (b), the second grinding includes wet grinding.

[0062] Wet grinding is highly efficient and produces no dust, eliminating dust pollution and facilitating laboratory and industrial production. Furthermore, it maintains process continuity with subsequent wet screening and wet gravity separation, enhancing operability and avoiding the crossover of dry and wet processes that would increase energy consumption and costs.

[0063] In some specific embodiments, step (c) further includes a step of sequentially performing solid-liquid separation and drying on the second gravity separation tailings before mixing them with the soda ash.

[0064] In some specific embodiments, step (c), the step of mixing and calcining the second gravity separation tailings with soda ash, specifically includes: mixing the second gravity separation tailings, the soda ash, and water and pressing them into blocks to obtain material blocks; and then calcining the material blocks.

[0065] By combining soda ash with the obtained secondary gravity separation tailings briquettes, the contact area between the two is increased, which facilitates the complete high-temperature reaction in the subsequent process.

[0066] In some specific embodiments, in step (c), the second gravity separation tailings are mixed with the soda ash according to a molar ratio of Si to Na of 2.5 to 4.5:1; wherein the molar ratio of Si to Na includes, but is not limited to, any one of 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or any range between the two.

[0067] In some specific embodiments, in step (c), the calcination temperature is 1250℃~1400℃, including but not limited to any one of 1250℃, 1300℃, 1350℃, and 1400℃ or any range between two of them; the calcination holding time is 1h~4h, including but not limited to any one of 1h, 1.5h, 2h, 2.5h, 3h, and 4h or any range between two of them.

[0068] In some specific implementations, in step (c), the cooling method includes quenching.

[0069] The quenching medium includes, but is not limited to, brine, water, mineral oil, and air.

[0070] Preferably, the quenching method includes water quenching.

[0071] In some specific embodiments, step (d) of dissolving and separating the crude sodium silicate specifically includes: crushing the crude sodium silicate, mixing it with water and heating it to dissolve, and then performing solid-liquid separation to obtain the sodium silicate solution.

[0072] After high-temperature reaction, the sodium silicate is quenched and crushed to a suitable particle size to facilitate subsequent dissolution.

[0073] Preferably, the mass fraction of the crushed material passing through a 60-mesh sieve is ≤30%, that is, the mass of the material passing through a 60-mesh sieve accounts for ≤30% of the total mass of the crushed material, including but not limited to any one of 30%, 25%, 20%, 15%, 10%, and 5%, or any range between two of them.

[0074] Preferably, the mass ratio of the crude sodium silicate to the water is 1:10 to 15; including but not limited to any one of 1:10, 1:11, 1:12, 1:13, 1:14, 1:15 or any range between two of them.

[0075] Preferably, during the heating and dissolving process, the temperature of the mixture is 50℃ to 65℃, including but not limited to any one of 50℃, 53℃, 55℃, 58℃, 60℃, 63℃, and 65℃, or a range between any two.

[0076] By using the aforementioned high liquid-to-solid ratio and simultaneously heating, all the sodium silicate obtained from the high-temperature reaction can be dissolved. Afterward, filtration is performed to remove some of the unreacted silicon powder, soda ash, and unreacted impurities, thus purifying the sodium silicate.

[0077] In some specific embodiments, step (d) involves evaporation under reduced pressure. Reduced pressure evaporation can increase the evaporation rate, improve evaporation efficiency, and shorten the precipitation and production time of sodium silicate.

[0078] In some specific implementations, in step (d), the cooling rate of the cooling crystallization is 6 to 12°C / h, including but not limited to any one of 6°C / h, 7°C / h, 8°C / h, 9°C / h, 10°C / h, 11°C / h, and 12°C / h, or any range between two of them.

[0079] By controlling the cooling rate of the crystallization process, sodium silicate powder particles with a better crystal appearance can be obtained, which is beneficial for its application.

[0080] Secondly, the present invention provides the application of sodium silicate obtained by the method described above for preparing sodium silicate from tailings of titanium zircon sand ore in papermaking, casting, titanium dioxide, soap, leather, construction, refractory materials, rubber, silica gel, molecular sieves, dyes and glass fibers.

[0081] It is understood that the sodium silicate obtained by this invention can be widely used in various fields, such as papermaking, casting, and as a raw material for preparing titanium dioxide, soap, leather, construction, refractory materials, rubber, silica gel, molecular sieves, dyes and glass fibers, but is not limited thereto.

[0082] Among them, titanium concentrate produced from titanium zirconium sand is an important raw material in the production process of titanium dioxide, while low modulus sodium silicate is the main raw material for silicon coating of titanium dioxide. This invention uses waste titanium zirconium sand tailings to produce sodium silicate, transforming front-end solid waste in the titanium field into back-end production materials, which plays an important supplementary role in the overall green cycle of the industry and improving the overall resource utilization of the industry.

[0083] Preferably, the purity of the sodium silicate is ≥93%, including but not limited to the point value of any one of 93%, 94%, 95%, 96%, 97%, 98%, 98.2%, 98.4%, 98.7%, 99%, 99.1%, and 99.5%, or the range between any two; more preferably, it is ≥98%.

[0084] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0085] To compare the purity of the sodium silicate products obtained in the various embodiments and comparative examples, the same batch of titanium zirconium sand tailings was used in the following embodiments and comparative examples of this invention. Its chemical composition, by mass percentage, was: SiO2 92.49%, TiO2 1.67%, ZrO2 0.91%, Fe2O3 1.06%, Al2O3 2.21%, with the balance being impurities (e.g., Cl, S, Na, K, Mn, and P). However, the titanium zirconium sand tailings that can be used in this invention are not limited to this, and the above chemical composition should not be considered as limiting the scope of this invention.

[0086] Example 1

[0087] The method for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation provided in this embodiment includes the following steps:

[0088] (1) The tailings of the titanium zircon sand ore beneficiation are subjected to a first wet grinding and wet screening using a 160-mesh vibrating screen to obtain the first screen oversize and the first screen undersize. The first screen oversize is controlled to account for 40% of the mass of the titanium zircon sand ore beneficiation tailings. Then the first screen oversize is subjected to a first shaking table gravity separation, with the stroke controlled at 17 mm and the stroke rate at 250 times / min to obtain the first gravity separation tailings.

[0089] (2) Mix the first gravity separation tailings with the first screen undersize and perform a second wet milling, controlling the proportion of the material on the 160-mesh screen to be 15 wt.% (i.e., the material on the 160-mesh screen accounts for 15% of the total mass of the material after the second wet milling), and then perform a second shaking table gravity separation on the material after the second wet milling, controlling the stroke to be 12 mm and the stroke to be 300 times / min to obtain the second gravity separation tailings.

[0090] (3) The tailings of the second gravity separation were filtered and dried. The mass fraction of SiO2 was 97.78%. The tailings of the second gravity separation were mixed with soda ash in a molar ratio of Si to Na of 3.5:1. Water was added to press the mixture into blocks (the mass of water was 10% of the total mass of the tailings of the second gravity separation and soda ash). The resulting material blocks were placed in a high-temperature melting device for high-temperature calcination. The calcination temperature was controlled at 1350℃ and the calcination time was 3h. After calcination, the material was quenched with water to obtain crude sodium silicate.

[0091] (4) The crude sodium silicate is crushed, and the mass fraction of the material passing through a 60-mesh sieve is controlled to be 20%. Water is then added to the crushed crude sodium silicate and heated to dissolve it. The mass ratio of crude sodium silicate to water is 1:12, and the heating temperature is 60°C. After complete dissolution, the solution is filtered while hot to obtain a sodium silicate solution. The sodium silicate solution is evaporated under reduced pressure until saturation, and then cooled to crystallize at a rate of 8°C / h. After complete crystallization, the solution is filtered and dried to obtain the sodium silicate product. The purity of the sodium silicate product obtained in this embodiment is 99.15%.

[0092] Example 2

[0093] The method for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation provided in this embodiment includes the following steps:

[0094] (1) The tailings of the titanium zircon sand ore beneficiation are subjected to a first wet grinding and wet screening using a 160-mesh vibrating screen to obtain the first screen oversize and the first screen undersize. The first screen oversize is controlled to account for 30% of the mass of the titanium zircon sand ore beneficiation tailings. Then the first screen oversize is subjected to a first shaking table gravity separation, with the stroke controlled at 17 mm and the stroke rate at 250 times / min to obtain the first gravity separation tailings.

[0095] (2) Mix the first gravity separation tailings with the first screen undersize and perform a second wet milling, controlling the proportion of the material on the 160-mesh screen to be 5 wt.% (i.e., the material on the 160-mesh screen accounts for 5% of the total mass of the material after the second wet milling), and then perform a second shaking table gravity separation on the material after the second wet milling, controlling the stroke to be 12 mm and the stroke to be 300 times / min to obtain the second gravity separation tailings.

[0096] (3) The tailings of the second gravity separation were filtered and dried. The mass fraction of SiO2 was found to be 96.54%. The tailings of the second gravity separation were mixed with soda ash in a molar ratio of Si to Na of 3.5:1. Water was added to press the mixture into blocks (the mass of water was 10% of the total mass of the tailings of the second gravity separation and soda ash). The resulting material blocks were placed in a high-temperature melting device for high-temperature calcination. The calcination temperature was controlled at 1350℃ and the calcination time was 3h. After calcination, the material was quenched with water to obtain crude sodium silicate.

[0097] (4) The crude sodium silicate was crushed, and the mass fraction of the material passing through a 60-mesh sieve was controlled to be 20%. Water was then added to the crushed crude sodium silicate and heated to dissolve it. The mass ratio of crude sodium silicate to water was 1:12, and the heating temperature was 60°C. After complete dissolution, the solution was filtered while hot to obtain a sodium silicate solution. The sodium silicate solution was evaporated under reduced pressure until saturation, and then cooled to crystallize at a rate of 10°C / h. After complete crystallization, the solution was filtered and dried to obtain the sodium silicate product. The purity of the sodium silicate product obtained in this embodiment was tested to be 98.49%.

[0098] Example 3

[0099] The method for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation provided in this embodiment includes the following steps:

[0100] (1) The tailings of the titanium zircon sand ore beneficiation are subjected to a first wet grinding and wet screening using a 160-mesh vibrating screen to obtain the first screen oversize and the first screen undersize. The first screen oversize is controlled to account for 40% of the mass of the titanium zircon sand ore beneficiation tailings. Then the first screen oversize is subjected to a first shaking table gravity separation, with the stroke controlled at 20 mm and the stroke rate at 225 times / min to obtain the first gravity separation tailings.

[0101] (2) Mix the first gravity separation tailings with the first screen undersize and perform a second wet milling, controlling the proportion of the material on the 160-mesh screen to be 15 wt.% (i.e., the material on the 160-mesh screen accounts for 15% of the total mass of the material after the second wet milling), and then perform a second shaking table gravity separation on the material after the second wet milling, controlling the stroke to be 15 mm and the stroke to be 250 times / min to obtain the second gravity separation tailings.

[0102] (3) The tailings of the second gravity separation were filtered and dried. The mass fraction of SiO2 was 96.38%. The tailings of the second gravity separation were mixed with soda ash in a molar ratio of Si to Na of 3.5:1. Water was added to press the mixture into blocks (the mass of water was 10% of the total mass of the tailings of the second gravity separation and soda ash). The resulting material blocks were placed in a high-temperature melting device for high-temperature calcination. The calcination temperature was controlled at 1350℃ and the calcination time was 3h. After calcination, the material was quenched with water to obtain crude sodium silicate.

[0103] (4) The crude sodium silicate was crushed, and the mass fraction of the material passing through a 60-mesh sieve was controlled to be 20%. Water was then added to the crushed crude sodium silicate and heated to dissolve it. The mass ratio of crude sodium silicate to water was 1:12, and the heating temperature was 60°C. After complete dissolution, the solution was filtered while hot to obtain a sodium silicate solution. The sodium silicate solution was evaporated under reduced pressure until saturation, and then cooled to crystallize at a rate of 8°C / h. After complete crystallization, the solution was filtered and dried to obtain the sodium silicate product. The purity of the sodium silicate product obtained in this embodiment was 98.21%.

[0104] Example 4

[0105] The method for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation provided in this embodiment includes the following steps:

[0106] (1) The tailings of the titanium zircon sand ore beneficiation are subjected to a first wet grinding and wet screening using a 160-mesh vibrating screen to obtain the first screen oversize and the first screen undersize. The first screen oversize accounts for 45% of the mass of the titanium zircon sand ore beneficiation tailings. Then the first screen oversize is subjected to a first shaking table gravity separation, with the stroke controlled at 17 mm and the stroke rate at 250 times / min to obtain the first gravity separation tailings.

[0107] (2) Mix the first gravity separation tailings with the first screen undersize and perform a second wet milling, controlling the proportion of the material on the 160-mesh screen to be 12 wt.% (i.e., the material on the 160-mesh screen accounts for 12% of the total mass of the material after the second wet milling), and then perform a second shaking table gravity separation on the material after the second wet milling, controlling the stroke to be 12 mm and the stroke to be 300 times / min to obtain the second gravity separation tailings.

[0108] (3) The tailings of the second gravity separation were filtered and dried. The mass fraction of SiO2 was 97.53%. The tailings of the second gravity separation were mixed with soda ash in a molar ratio of Si to Na of 3.5:1. Water was added to press the mixture into blocks (the mass of water was 10% of the total mass of the tailings of the second gravity separation and soda ash). The resulting material blocks were placed in a high-temperature melting device for high-temperature calcination. The calcination temperature was controlled at 1275℃ and the calcination time was 2h. After calcination, the material was quenched with water to obtain crude sodium silicate.

[0109] (4) The crude sodium silicate was crushed, and the mass fraction of the material passing through a 60-mesh sieve was controlled to be 20%. Water was then added to the crushed crude sodium silicate and heated to dissolve it. The mass ratio of crude sodium silicate to water was 1:12, and the heating temperature was 60°C. After complete dissolution, the solution was filtered while hot to obtain a sodium silicate solution. The sodium silicate solution was evaporated under reduced pressure until saturation, and then cooled to crystallize at a rate of 8°C / h. After complete crystallization, the solution was filtered and dried to obtain the sodium silicate product. The purity of the sodium silicate product obtained in this embodiment was tested to be 98.16%.

[0110] Example 5

[0111] The method for preparing sodium silicate from tailings of titanium zircon sand ore beneficiation provided in this embodiment is basically the same as that in embodiment 1, except that: in step (1), the material on the first 160-mesh screen accounts for 10% of the mass of the tailings of titanium zircon sand ore beneficiation, and the stroke of the first shaking table gravity separation is controlled to be 20 mm and the number of strokes is 150 times / min; at the same time, in step (2), the material proportion of the material on the 160-mesh screen is controlled to be 2 wt.%, and the stroke of the second shaking table gravity separation is controlled to be 20 mm and the number of strokes is 200 times / min.

[0112] In this embodiment, the mass fraction of SiO2 in the second gravity separation tailings after pressure filtration and drying in step (3) is 93.24%; the purity of the sodium silicate product obtained in this embodiment is 96.37%.

[0113] Example 6

[0114] The method for preparing sodium silicate from tailings of titanium zircon sand ore provided in this embodiment is basically the same as that in Example 1, except that: in step (1), the material on the first 160-mesh sieve accounts for 35% of the mass of the tailings of titanium zircon sand ore, and in step (2), the material on the 160-mesh sieve accounts for 8 wt.%; at the same time, in step (3), the calcination temperature is controlled at 1150℃ and the calcination time is controlled at 5h.

[0115] In this embodiment, the mass fraction of SiO2 in the tailings after pressure filtration and drying in step (3) is 97.39%; the purity of the sodium silicate product obtained in this embodiment is 95.46%.

[0116] Comparative Example 1

[0117] The method for preparing sodium silicate from titanium zircon sand tailings provided in this comparative example is basically the same as that in Example 1. The difference is that steps (1) and (2) in Example 1 are replaced with the following steps: the titanium zircon sand tailings are wet-milled, and the proportion of material on the 160-mesh screen is controlled to be 15 wt.% (i.e., the material on the 160-mesh screen accounts for 15% of the total mass of the material after wet milling). Then, the material after wet milling is subjected to gravity separation on a shaking table, with the stroke controlled to be 12 mm and the stroke rate to be 300 times / min, to obtain gravity-separated tailings.

[0118] The mass fraction of SiO2 in the gravity separation tailings after pressure filtration and drying in step (3) of this comparative example is 88.50%; the purity of the sodium silicate product obtained in this comparative example is 90.37%.

[0119] Comparative Example 2

[0120] The method for preparing sodium silicate from titanium zircon sand tailings provided in this comparative example is basically the same as that in Example 1. The difference is that steps (1) and (2) in Example 1 are replaced with the following steps: the titanium zircon sand tailings are wet-milled and wet-screened using a 160-mesh vibrating screen to obtain the first undersize material (the first oversize material is discarded). The first oversize material of the 160-mesh screen accounts for 40% of the mass of the titanium zircon sand tailings. Then, the first undersize material is subjected to gravity separation on a shaking table with a stroke of 12 mm and a stroke rate of 300 times / min to obtain gravity-separated tailings.

[0121] The mass fraction of SiO2 in the gravity separation tailings after pressure filtration and drying in step (3) of this comparative example is 87.66%; the purity of the sodium silicate product obtained in this comparative example is 93.92%.

[0122] Comparative Example 3

[0123] The method for preparing sodium silicate from tailings of titanium zircon sand provided in this comparative example is basically the same as that in Example 1, except that filtration is not performed in step (4).

[0124] The mass fraction of SiO2 in the gravity separation tailings after pressure filtration and drying in step (3) of this comparative example is 97.63%; the purity of the sodium silicate product obtained in this comparative example is 80.45%.

[0125] As can be seen from the above examples and comparative examples, the sodium silicate obtained in Examples 1-4 has high purity and low impurity content. In Examples 5 and 6, the purity of the sodium silicate decreased somewhat due to adjustments in some parameters.

[0126] In contrast, Comparative Examples 1 and 2, which involved a single grinding and re-selection process, resulted in a significant increase in the impurity content and a significant decrease in the purity of the prepared sodium silicate.

[0127] Comparative Example 3 also resulted in a decrease in the purity of the prepared sodium silicate because it was not filtered after dissolution.

[0128] In summary, the method for preparing sodium silicate from tailings of titanium-zirconium sand ore provided by this invention can obtain high-purity sodium silicate. Furthermore, by controlling the preparation parameters, the purity of the sodium silicate can be further improved.

[0129] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, without departing from the spirit and scope of the present invention; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing sodium silicate from tailings of titanium-zirconium sand ore beneficiation, characterized in that, Includes the following steps: (a) The tailings of the titanium-zirconium sand ore separation are subjected to a first grinding and a first screening to obtain a first oversize and a first undersize; the first oversize is subjected to a first gravity separation to obtain a first gravity separation tailings; in step (a), the titanium-zirconium sand ore separation tailings include waste tailings obtained after separating titanium-zirconium sand ore from at least one of ilmenite, rutile and zirconium silicate; in step (a), the mesh size of the screen used in the first screening is 150~200 mesh; in step (a), the mass of the first oversize is 30%~50% of the mass of the titanium-zirconium sand ore separation tailings; the stroke of the first gravity separation is 15mm~20mm, and the stroke rate is 200 times / min~300 times / min; (b) The first gravity separation tailings are mixed with the first screen undersize and then subjected to a second grinding, followed by a second gravity separation to obtain the second gravity separation tailings; in step (b), the proportion of screen undersize material with a mesh size of 160 or above in the second grinding is 5wt.%~20wt.%; the stroke of the second gravity separation is 10mm~15mm, and the number of strokes is 250 times / min~350 times / min; (c) The tailings from the second gravity separation are mixed with soda ash and calcined, and then cooled to obtain crude sodium silicate. (d) The crude sodium silicate is dissolved and separated into solid and liquid components to obtain a sodium silicate solution; The sodium silicate solution is heated and evaporated to a saturated solution, and then cooled and crystallized to obtain the sodium silicate.

2. The method for preparing sodium silicate from tailings of titanium-zirconium sand ore according to claim 1, characterized in that, In step (a), the main component of the titanium zircon sand tailings includes quartz.

3. The method for preparing sodium silicate from tailings of titanium-zirconium sand ore according to claim 1, characterized in that, It includes at least one of the following features (1) to (3): (1) In step (a), the first grinding includes wet grinding; (2) In step (b), the second grinding includes wet grinding; (3) In step (c), before the second gravity separation tailings are mixed with the soda ash, the second gravity separation tailings are further subjected to solid-liquid separation and drying in sequence.

4. The method for preparing sodium silicate from tailings of titanium-zirconium sand ore according to claim 1, characterized in that, It includes at least one of the following features (1) to (4): (1) In step (c), the step of mixing and calcining the second gravity separation tailings with soda ash specifically includes: mixing the second gravity separation tailings, the soda ash and water and pressing them into blocks to obtain material blocks; and then calcining the material blocks. (2) In step (c), the second gravity separation tailings are mixed with the soda ash according to the molar ratio of Si to Na of 2.5 to 4.5:1; (3) In step (c), the calcination temperature is 1250℃~1400℃, and the calcination holding time is 1h~4h; (4) In step (c), the cooling method includes quenching.

5. The method for preparing sodium silicate from tailings of titanium-zirconium sand ore according to claim 1, characterized in that, In step (d), the steps of dissolving and separating the crude sodium silicate specifically include: crushing the crude sodium silicate, mixing it with water and heating it to dissolve, and then separating the solid and liquid to obtain the sodium silicate solution.

6. The method for preparing sodium silicate from tailings of titanium-zirconium sand ore according to claim 5, characterized in that, The mass fraction of the material passing through a 60-mesh sieve is ≤30%.

7. The method for preparing sodium silicate from tailings of titanium-zirconium sand ore according to claim 5, characterized in that, The mass ratio of the crude sodium silicate to the water is 1:10~15; And / or, during the heating and dissolving process, the temperature of the mixture is 50℃~65℃.

8. The method for preparing sodium silicate from tailings of titanium-zirconium sand ore according to claim 1, characterized in that, In step (d), the evaporation includes vacuum evaporation; And / or, in step (d), the cooling rate of the cooling crystallization is 6~12℃ / h.

Images