Silica processing plant and method for high-purity silica manufacturing
Patent Information
- Application Number
- PCT/IB2025/054026
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-04-17
- Publication Date
- 2026-10-22
Smart Images
Figure IB2025054026_22102026_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Title of Invention : Silica Processing Plant and Method for High-Purity Silica Production
[0003] Technical Field
[0004] [1] This invention relates to a novel process and process plant for the purification of silica sand, specifically tailored for the glass manufacturing industry and primary initiating to the highly purified silica generation for the manufacturing of silicon ingots and then silicon wafers for the semiconductor industry. Silica sand is the critical raw material in both the glass and semi-conductor manufacturing industries, where its purity and particle size significantly influence the quality and efficiency of both manufacturing processes. This invention provides a cost-effective method for large-scale production of purified silica sand that meets the stringent quality standards required for various types of glass products, including container glass, flat glass, specialty glass and initial raw material with further purification steps for semiconductor industry. The proposed process addresses key industry challenges such as achieving superior glass clarity in glass related manufacturing processes as well as higher purity silica for silicon ingot manufacturing, the first phase of semiconductor industry. Optimizing energy efficiency, and reducing environmental impacts, while being adaptable to different scales of production are the important industrial approaches in this manufacturing process .
[0005] Background Art
[0006] [2] Silica sand purity is a cornerstone of glass as well as in semiconductor industry, and its significance cannot be underated. Impurities, particularly iron oxides and other related heavy minerals, have a detrimental impact on the clarity and aesthetic properties of glass, often leading to discoloration and structural weaknesses. This is more crucial when its going to apply as the primary process of silicon ingot manufacturing to reach the level of 99.99999% of silica for semiconductor industry .Traditional purification methods, including magnetic separation, flotation, and gravity-based separation, have been widely used toaddress these issues. Magnetic separation is typically utilized to remove iron- bearing impurities like ilmenite, while flotation targets non-magnetic minerals such as feldspar and mica.
[0007] [3] Despite their widespread adoption, these methods have inherent limitations. They often struggle to handle silica deposits with high levels of impurities particularly those found in deeper geological layers. Furthermore, achieving finer particle sizes through these methods is challenging, which is a growing requirement for modern glass furnaces to reduce energy consumption as well for the silicon ingot manufacturing process for semiconductor industry. Another critical drawback of conventional methods is the high operational cost and material losses, especially in processes involving oversized particles exceeding 0.71 mm in diameter, which can result in rejection rates as high as 40% in some fields which towards the higher oversized % availability in nature.
[0008] [4] Environmental sustainability has become an essential consideration in the silica sand industry, prompting the development of water recycling systems, managing excavated sites and energy-efficient technologies. However, many of these advancements are inadequate for addressing the dual challenges of achieving high-purity silica and minimizing environmental impact. This invention bridges these gaps by proposing an innovative, comprehensive process that ensures the efficient use of silica deposits, even those with higher impurity levels, while significantly reducing energy consumption and waste.
[0009] [5] The demand for high-quality silica, driven by industries such as glass packaging (Container-Bottles), construction, renewable energy and silicon ingot manufacturing has emphasized the need of advanced silica sand purification methods. The efficiency of glass and silicon ingot manufacturing hinges on achieving an optimal balance of particle size distribution, impurity removal, and resource utilization. Silica sand with a higher SiO2 percentage and uniform particle size distribution with its optimum finer range is critical for efficient melting in glass furnaces, as well as in silicon ingot manufacturing process, since it lowers melting temperatures and energy consumption. Conversely, impurities such as iron oxides, other types of heavy minerals and clay-type binders adversely affect the silica quality which negatively affect the clarity, strength, and production consistency of glass as well as purity in silicon ingot manufacturing process.[6] Natural silica deposits vary significantly in quality. While the upper layers of silica fields are often suitable for glass manufacturing, deeper layers typically contain higher levels of impurities, leading to their underutilization. Conventional methods for processing such deposits often fail to meet quality standards without resorting to costly chemical treatments, resulting in significant material wastage and environmental degradation. Additionally, oversized particles and by-products exacerbate inefficiencies, as they hinder these key processes and increase rejection rates. This invention introduces a sustainable and efficient process that addresses these challenges comprehensively, ensuring high-purity silica production with minimal environmental impact and cost.
[0010] Summary of Invention
[0011] [7] The invention, which is the processing method and processing plant represents a transformative approach to silica sand purification, integrating advanced size reduction, impurity removal, and energy-saving techniques. It offers a sustainable, cost-effective, and highly efficient solution for producing high-purity silica tailored to meet the evolving demands of modem glass manufacturing and turbulent global semiconductor industry, which the world is highly focusing due to its massive demand. This innovation not only enhances the quality and competitiveness of glass products but also contributes to the industry's broader goals of sustainability and environmental stewardship.
[0012] Technical Problem
[0013] [8] The glass and silicon wafer industry are constrained by several technical and economic challenges in silica sand processing. Glass melting as well high purity silica processing and subsequent process steps towards silicon ingot manufacturing is inherently energy-intensive, and silica, being the hardest materials in the raw mix in glass batch , plays a significant role in determining furnace temperatures in both approaches. Higher melting temperatures lead to increased fuel consumption, making energy costs a critical bottleneck in the economic viability of glass manufacturing as well semiconductor industry.
[0014] [9] Another significant issue is the rejection of oversized silica particles, which results in substantial material losses. The inefficiency of existing processes to handlethese particles effectively has led to the wastage of valuable resources and heightened environmental concerns. Furthermore, the under-utilization of lower- quality silica deposits due to their high impurity levels contributes to resource inefficiency and environmental degradation. These challenges underline the need for an innovative approach to silica sand purification that optimizes resource use, reduces energy consumption, and enhances environmental sustainability.
[0015] Solution to Problem
[0016]
[0010] The proposed invention which is a process technology and processing plant which provide an integrated solution to the challenges in silica sand purification. A key innovation is the use of wet media crushing, which efficiently reduces particle size to meet modem specifications such as 0.315 mm while minimizing energy consumption. This method ensures a uniform particle size distribution, which is essential for reducing furnace temperatures and enhancing the melting efficiency in glass manufacturing and silicon wafer manufacturing for semiconductor industry.
[0017]
[0011] Spiral separation is employed as a gravity-based method to remove heavy minerals like ilmenite, thereby significantly reducing the iron content in the silica sand. This step is critical for achieving the clarity and quality required for highgrade glass products as well primary raw materials for Semiconductor industry. Wet media sieving, another innovative feature of the process, eliminates the need for energy-intensive drying steps before classification. This not only lowers operational costs but also addresses environmental concerns by reducing fuel consumption and emissions.
[0018]
[0012] The invention further optimizes the utilization of silica deposits by enabling the processing of lower-quality layers with higher impurity levels. Through advanced impurity removal techniques, such as the elimination of clay-type binders, these layers can be transformed into high-purity silica suitable for glass production. This approach maximizes resource efficiency while minimizing waste and environmental impact.Advantageous Effects of Invention
[0019]
[0013] This invention offers several distinct advantages over conventional silica sand purification methods. By removing impurities more effectively, it ensures superior glass clarity and quality, making it suitable for high-end applications such as semiconductor manufacturing. The optimized particle size distribution achieved through this process significantly reduces energy consumption in glass melting, leading to substantial cost savings and enhanced energy efficiency.
[0020]
[0014] The ability to process deeper layers of silica deposits reduces reliance on topquality raw materials and minimizes waste, promoting sustainable resource utilization. Additionally, the elimination of energy-intensive drying steps and the use of advanced sieving techniques lower operational costs and environmental emissions, making the process economically and environmentally viable for large- scale glass production.
[0021] Brief Description of Drawings
[0022]
[0015] FIG.1 Shows the overview of the silica processing plant.
[0023] Description of Embodiment
[0024]
[0016] The “excavated Raw silica” heap (01) introduce to the invented new silica processing plant where the process has been designed which ultimately could make the compatibility to process any type of “silica fields”, which meets minimum requirements as primary raw materials for both commercial glass manufacturing as well semiconductor industry. This new invented process could be treated not only for the surface “white layer with average impurities”, but also up to the most bottom level dark colored silica layers which contains higher level of impurities than said top layer. This field arrangements in the natural silica dunes can be varied as in some fields in the world, this silica-based layer could be found several meters below the “Non commercially valuable top silica layers”. Hence the process versatility is very high with this new invention. The said raw silica directly put into the main feeding hopper (02) is designed considering all angles andproposed pneumatic knockers (03) fixed to the side walls of the hopper and lump crushers (04) to make it smooth feeding to the conveyer (05) installed at the bottom opening of the feeding hopper.
[0025]
[0017] The raw material fallen to the feeding Conveyor (05) which takes the material to an upper level which directly falls on to a 5mm square hole vibrating Pll Screen (07) which has high pressure water jet spray above the screen bed. Here the Polyurethane is the best media for a sieving process of larger sized particles (up to 5 to 6 mm) in the field due to the high abrasiveness of the “silica”. The aperture size of this screen can be decided to cover the maximum particle size of the field which needs to be 100%(almost) sieved within this process as the other objectives of this screen is to remove all abnormal larger sized impurities, large stones, bio mass debris etc., in parallel to primary washing process .
[0026]
[0018] The slurry-based silica flow collecting the bottom of the said Pll screen (Under size of the mesh aperture) directly introducing to the entry of a rotating “silica sand washing drum” (08) which help to remove loosely bonded clay around the sand particle, while floating the light weight impurities such as more finer range black sand (Ilmenite) and other floating finer range heavy mineral category. Since usually in nature the heavy minerals, which almost in the category of impurities in silica fields representing very finer size range which can float with the disturbed moving water. Hence the removed clay mixed water and this finer fraction which can float and discharge with the water at the back end (feeding end) of the drum. Which in design it makes an 1-2-degree inclinations towards feeding end of the washing drum (08) while the product moves towards the front end using the internally fixed spiral-based flutes which focused the movements towards the front against the rotating side and falls in to a Collecting Hopper (09) with a Slurry pump (10).
[0027]
[0019] The same slurry, pumping to a hydro cyclone (11. a) fixed at the top of main gravity separating unit using to remove heavy minerals called “Spiral Bank” (12. a). The no of turns (in most cases 3), the combination of the spirals for each bank can be evaluated against the desired feeding rate subjected to the designed capacity of the silica processing plant. The bottom of the spiral bank it collecting the one part at the axis of the spiral, the main rejection, black sand(12.a.R) and directly dumping to a separate bin.
[0020] The production from the spiral bank (12. a) indicated as (12.a.P) representing the middling and tailings , a slurry formation collected and diverted toward a collecting hopper(9.a) and slurry pump(10.a) diverting to the second spiral bank of the process (12.b) through a Hydro cyclone (11.b), the similar process arrangements will be taken place here with (12.b) such as above mention (12. a) Spiral bank which the rejection , heavy mineral of (12. b) nominated as (12.b.R) collecting at a separate ground bin. The separators using at each spiral operations which split the common spiral slurry floor to segregate production (12.a.P and 12.b.P) and rejection (12.a.R and 12.b.R) may vary as per the process requirements and same can be manually adjusted provided (separators) at the bottom part of each spiral. The production from Spiral bank (12.b.P), which feed directly to the top of two wet media high vibratory screens (14. a and 14.b) with unique rate through the slurry collecting hopper (9.b) and slurry pump 10.b. Each screen is equipped with four replaceable panels, allowing adjustments to achieve the desired aperture size for optimizing size fractioning, ensuring minimal loss of good sand moving to the rejects and vice versa. The undersized material from this operation is treated as production (14.a.b.(-)), maintained the upper cut as 0.315mm and directed to a final separate spiral bank (12.c) via a collecting hopper (09. c) and slurry pump( 10.c) through the third hydro cyclone (11.c). Third spiral bank (12. C) which removes further impurities such as black sand (12.C.R). The purified product, (12.C.P) is diverted to another slurry collecting hopper (9.d) and Slurry Pump (10.d). To minimize the waste of good silica category within the overall process, the rejections collected from the 2ndand 3rdspiral processes (12.b.R and 12.C.R) are diverted to Wet High Intensity Magnetic separator (WHIM) (23. a). The advantage of this operation is that the particle distribution of the product of WHIM (23. a. P) is mostly towards finer fraction. It gives positive impact on the energy cost in any commercial melting process which Silica uses as key raw material. This fraction can be more useful in glass melting process where the criticality of silica percentage is not strict compared to the manufacturing of silicon ingots, silicon wafer production which used for chip manufacturing. In glass melting furnaces, due to its higher draw of Tones Per Day (TPD), the particle size is critically important to control the energy factor. While contributing even smaller percentages of this fine fraction, production of WHIM (23. a. P) by mixing with the two final product outputs (21 (-)) and (12.c. P), the overall final particle distributionas the common output of the fifth slurry pump (1O.d), the curve of particle distribution becomes more healthier for glass melting industry. This extracting process of finer fraction and mixing the same with final key process quality output can play very significant role at defining higher melting rate (Mt / Sq.mtr) commercial glass manufacturing furnaces. Where the major capital investment in a glass industry is the melting furnaces which varies starting from domestic range of 10TPD to 350TPD and above in some cases further. The higher heat resistance cost of refractory is the key factor which in higher melting rate furnaces the volume of this type refractory categories can be drastically reduced by making its investment cost effective. Which in Glass melting it can be used above 99. % processed silica when it’s addressed the lower impurity rates as its commercial requirements.
[0028]
[0021] The oversized sand from the first two screens (14.a(+), 14.b.(+)) is directed to a common distributor (17) positioned above the two wet media crushers (19) operating in Parallel. This crushing step is critical as it serves multiple purposes. The output of the same including maintaining the minimum iron content, means impurities and then divert to the final wet media high vibratory screen (21). and the dual treated this final production, under sized of the said screen, 21 (-), which maintaining upper cut as 0.315 mm can use as the processed raw material in Glass melting Industry. The grinding media (18) used in this process can be adjusted by varying the size combination against the diameter of each category which most probably three types of diameters using from 1” to 2” in this type of raw silica distribution which extracted from the silica Dunes. This is based on continuous process trials subjected to the input particle distribution of Raw silica and ultimate objective on desired specifications to feed the glass melting furnaces. A provision for a third crusher (20) is included for future requirements against the capacity enhancement. At the same time, the oversized of final screen (21) treated as (21(+)) is allowed to accumulate for a certain period of time and introduces similar crushing process (19. a) and proceed the standard steps. This highest quality level silica, generating within the process is with the minimum impurity level which can be used as initial raw material to the semiconductor industry. It gives more advantages than the above said production (21 (-)) of said screens.
[0022] To get the overall output the undersized material of final screens, (21(-)) is combined with the product output from the spiral bank (12.c) treated as (12.C.P) and the final output (23. a. P) of WHIM (23. a) collecting together at last. These three good quality outputs diverting to the final collecting hopper 9.d and Slurry pump 1O.d is introduced into the flat-bottom classifier (23) via a hydro cyclone (11.d). This classifier facilitates a highly sensitive operation, where cleaned high- pressure water (25) is introduced at the bottom through a rubberized bubbling chamber. This mechanism efficiently removes low weight finer clay and black sand particles(floating) if there any further, which are discharged through an overflow circular duct fixed around the flat bottom classier at the top and divert to the ground bin (26). After maximizing water removal, the final product is collected from the bottom of the flat-bottom classifier and is ready to be fed into the commercial glass production as well as introduce as quality raw material to silicon ingot manufacturing process.
[0029]
[0023] The string effect of the high vibratory wet media screens requires meticulous attention when finalizing the arrangements or combinations of panels fixed within the screens (14. a), (14. b) and finally screen (21). Any desired and pre-selected aperture size can be introduced based on specific process requirements. A detailed investigation is necessary to analyze the release of oversized particles (grain sizes above the desired upper cut level) in relation to undersized particles. This process must account for the applied mesh size and the panel combination to ensure the balance and control of the final allowable percentage of oversized material. These parameters should adhere to the specifications outlined by the glass and semiconductor industry.
[0030]
[0024] The selection of grinding media (18) for "wet media crushing" includes critical factors such as size, size combinations, and chemical composition. The optimal size combination of grinding media in the continuous crushing ball mill (19,20) should be determined through experimental results and considering the raw material feeding rate.
[0031]
[0025] In the majority of silica dunes, the larger grain size layers tend to have fewer impurities, with the bottom layers typically containing finer grains mixed with heavier minerals such as Ilmenite, Rutile, Zircon, etc. This natural distribution may vary from field to field and country to country. However, in most dune deposits,the focus on "larger grain sizes" tends to minimize the impact of heavy minerals. This is because oversized fractions can be separated with minimal impurities during processing.
[0032]
[0026] When these larger particles are crushed to a finer size, the resulting silica is ideal for glass melting for above 99% silica content, and for higher quality levels expecting such a way that 99.9999% of silica for Semiconductor industry while introducing next treatment process providing an economically viable solution, provided that the "upper cut" during crushing is effectively managed. To enhance the quality, it is possible to incorporate the naturally occurring finer fraction, which may have slightly higher impurity levels compared to the oversized fraction, after sieving. This can be blended with the crushed oversized fraction in an optimal combination to meet the desired final iron content in the processed silica sand. For most glass furnaces, the maximum allowable iron content in silica sand typically ranges from 0.03% to 0.04% while it moves further to semiconductor industry, this is more restricted which the above process re-shuffling it can be gained. As an example, the major part of the Production can be captured for Glass as mentioned above form the combination of three outputs ((24. a. P), (12.C.P) and (21(-)) are finally collected to the bin (24) after the flat bottom classifier (23) operation. Where the higher volume requirement for glass melting. The balance part gaining from final oversized crushing which the output mentioned as (28) which can be used with high quality lower capacity requirement-based silicon ingot manufacturing due its more purity level.
[0033]
[0027] The selection of grinding media (18) is critical, as many dry crushing methods, such as those using hammer mills or roller crushers, introduce unnecessary process restrictions and practical issues. In some wet media ball mills or rod mills, natural large silica pebbles, manganese balls, or large steel rods are used. This approach works to some extent in industries like sheet glass production. However, when it comes to higher-quality glass or semiconductor industry the clarity becomes a significant concern. Natural silica pebbles, with their relatively low hardness compared to other grinding media, do not provide an optimal solution for achieving the desired grinding efficiency due to low hardness .
[0034]
[0028] For this reason, hard alumina balls (cast molded) were selected with carefully chosen size combinations. The key objective is that, in all glass manufacturingprocesses, a certain percentage of alumina is typically included in the glass raw material batch. During the highly abrasive silica grinding process in the ball mill, a small percentage of alumina can mix with the silica product due to wear and tear on the alumina balls. By selecting hard alumina balls as the grinding media, this slight increase in alumina content can be accounted for in the final silica output. The balance of alumina can then be adjusted during the glass batch mixing process to meet the required alumina levels for the final glass product. Further working on high quality silica manufacturing for semi-conductor industry it can be focused even natural silica pebbles as selection of grinding media as a remedial action of controlling the alumina addition to the final product.
[0035] Mode of the Invention
[0036]
[0029] The present invention relates to a method for processing raw silica to obtain high-purity silica suitable for glass manufacturing and semiconductor applications. The method involves a sequence of mechanical, hydraulic, and magnetic separation processes to systematically refine silica by removing impurities such as iron and ilmenite.
[0037]
[0030] In the initial stage, raw silica is fed into a hopper (2) equipped with pneumatic knockers (3) and lump crushers (4) to break down large particles. The silica is then transported via a conveyor (5) to a mechanically vibrating Pll screen (7) with an aperture size of 5 mm to 6 mm, which removes oversized particles and allows high-pressure waterjets to initiate the washing process.
[0038]
[0031] The partially cleaned silica is transferred into a low-rpm washing drum (8), inclined at 1.5 - 2 degrees towards the feeding end, ensuring thorough washing and removal of unwanted residues. The washed silica is collected in a rubber- lined hopper (9) and pumped using a slurry pump (10) while maintaining a silica- to-water ratio of 40:60. The slurry is then subjected to cyclone separation in a hydro cyclone (11. a), where vortex forces aid in the classification of particles inside the hydro cyclone.
[0039]
[0032] The output of the hydro cyclone is processed through a series of spiral banks (12. a) that utilize centrifugal force to achieve gravity-based separation. The first spiral bank generates two outputs: a primary silica fraction or the production(12.a.P) and rejects (12.a.R). The primary silica fraction is directed for further refining using a collecting hopper (9. a) and slurry pump (10. a) through the second hydro-cyclone (11.b) and second spiral bank (12. b). The output of the spiral bank(12.b.P) is diverting to a wet media separation screens (14. a and 14.b) in equal quantities, using collecting hopper (9.b) and slurry pump (10.b). The rejects (12.b.R) from the spiral bank (12. b) undergo additional purification through a wet high-intensity magnetic separator (WHIM)(23.a) to eliminate iron and ilmenite impurities, (23. a. R). The product from the WHIM is directed to fifth collecting hopper (9.d) and fifth slurry pump (10.d).
[0040]
[0033] Oversized particles ((14.a.(+), 14.b(+)) separated from the wet media screens (14. a) and (14.b), are directed to crushers (19) containing grinding media (18) to achieve finer particle sizes. A second filtration screen (21) further separates fine silica from crushed oversized particles, which the oversized material of wet media screen 21, 21(+) undergoing additional crushing (19. a) to produce high-purity silica (28) using separate combination of grinding media. This time the grinding media, 18. a silica epbbles can be used to control impurity level and this output, (28) , suitable for semiconductor applications.
[0041]
[0034] Finally, fine silica21 (-) from the second filtration screen (21) and the output 12.C.P of third spiral bank 12(c) and the product 23. a. P of WHIM , 23.a are directed to a flat-bottom classifier (23) via a hydro cyclone (11.d), ensuring the removal of residual impurities. The final output (24) is high-purity silica, suitable for use in the glass industry.
[0042] Industrial Applicability
[0043]
[0035] The proposed system is efficient in silica processing for glass industry and also provide basic raw material with less impurities suitable for further processing for semiconductor manufacturing industry.Brief Description about the drawings
[0044]
[0036]
[0045]
[0046]
Claims
1. A silica processing plant for producing high-purity silica suitable for glass and semiconductor applications, comprising:a raw silica feeding unit including a hopper equipped with pneumatic knockers and lump crushers;a vibrating polyurethane screen with a waterjet system for removing oversized particles and initiating primary washing;a rotating silica washing drum inclined toward the feed end and fitted with internal spiral flutes for clay removal, impurity flotation and moving particles against the inclination toward discharge end;a hydrocyclone connected to a first spiral gravity separator for separating illmanite and heavy mineral impurities;at least one additional spiral gravity separator connected via hydrocyclone and slurry pump for further purification of middlings; a wet high-intensity magnetic separator (WHIM) for recovering fine silica from spiral rejects;a plurality of wet media vibratory screens with replaceable mesh panels for size fraction control;at least one wet media crusher with adjustable grinding media for reducing oversized silica particles;a flat-bottom classifier receiving combined final product streams and equipped with a high-pressure water injection system to remove light clays and residual impurities;and a system of slurry hoppers and pumps interconnecting each unit to enable continuous wet processing.
2. The plant of claim 1, wherein the grinding media comprises cast alumina balls with diameters ranging from 0.5 to 1.5 inches.
3. The plant of claim 1, wherein the polyurethane screen includes mesh panels with selectable aperture sizes ranging from 5 mm to 6 mm.
4. The plant of claim 1, wherein the flat-bottom classifier comprises a rubber-lined water-bubbling chamber adapted to remove floating fines and clays.
5. The plant of claim 1, further comprising a third wet media crusher and a recirculation system for oversized final screen fractions intended for semi conductor-grade appli cati ons .
6. The plant of claim 1, wherein at least three distinct slurry pumps and hydrocyclones are configured to operate in series with spiral banks for staged gravity separation.
7. The plant of claim 1, wherein the plant includes a final mixing stage for blending screen outputs, spiral outputs, and WHIM outputs to achieve a tailored particle size distribution curve for glass furnace efficiency.
8. A method for processing raw silica into high-purity silica suitable for glass and semiconductor manufacturing, comprising the steps of:feeding raw silica into a hopper and crushing large particles; screening the material using a polyurethane mesh screen under high-pressure water spray;washing the undersized slurry in a rotating drum inclined toward the feed side, moving floating impurities to the feeding end and the product moving to the dischargeend classifying the slurry via hydro-cyclone and feeding it to spiral gravity separators for heavy mineral separation;subjecting spiral rejects to magnetic separation using a WHIM to recover usable fine silica;screening spiral outputs using high-frequency wet media vibratory screens;crushing oversized screen fractions using wet media crushers; classifying the combined product stream using a flat-bottom classifier with high-pressure water injection;andcollecting the final purified silica product.
9. The method of claim 8, wherein the silica-to-water ratio is maintained at approximately 40:60 during all slurry transport and separation operations.
10. The method of claim 8, wherein the recovered WHIM product is blended with outputs from vibratory screens and spiral classifiers to enhance particle size distribution and to enhance particle size distributions towards the finer range, reducing overall rejection.
11. The method of claim 8, wherein screen panels are adjusted to achieve a maximum particle size cut-off of 6 mm for use in high-efficiency higher melting rate glass furnaces.
12. The method of claim 8, wherein the grinding media used in the crushers are composed of cast alumina balls that contribute to controlled alumina levels in the final product for glass manufacturing.
13. The method of claim 8, further comprising reprocessing the oversized final screen fractions through an additional wet media crusher, with silica as grinding media for semiconductor-grade output.
14. The method of claim 8, wherein the final product contains iron levels of between 0.03% to 0.04% for semiconductor applications.
15. The method of claim 8, wherein the spiral gravity separation is performed in at least three stages with hydrocyclones connected in series.
16. The method of claim 8, wherein the flat-bottom classifier uses an annular overflow duct to discharge clay-rich slurry fractions and light-weight floating mineral impurities.
17. The method of claim 8, wherein each screen and classifier stage is monitored and controlled for adjustable throughput and precision particle targeting.