To cope with the large variety of separation tasks in the various Mining and Refining applications, Sefar has developed a dedicated range of filter solutions in order to maximize the performance of each utilized filter equipment. We focus on improving five aspects of filtration: the cost of production, the quality of the refined product, productivity as well as safety and environmental footprint. All mentioned aspects are remarkably improved by using Sefar filter solutions.
Sefar Filter Solutions for the Mineral Industry
In today’s demanding solid-liquid and solid-gas separation processes, it is crucial to achieve best possible production efficiency along with trouble-free filter operation. In order to improve the production yield and decrease the plant's total cost of ownership. Sefar offers a wide selection of proven filtration and separation products, backed by an experienced staff of industry experts in following mining and refining applications.
Base and precious metals
Fertilizers (Phosphate, Potash)
Kaolin and clay
Subsidiaries in 26 countries provide local technical service for the broad range of solutions supplied to the various industries and equipment.
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Alumina & Bauxite Industry
Pregnant liquor security filtration on Gaudfrin Diastar filter using Sefar filter bags
During refining of alumina from bauxite, filtration and separation processes play a significant role which are carried out under most challenging conditions. The major production process applied is called the Bayer process.
As worldwide alumina demand is steadily increasing, many plants have to push their capacity to the limit. By using Sefar filter solutions, our customers profit from an overall improved total cost of ownership (TCO), increase their production yield and lower their filtration cost per ton of alumina manufactured. Sefar provides all kinds of filter solutions, covering the value chain of Alumina refineries during the transformation of Bauxite.
On the red side of the process, Sefar offers worldwide proven filter solutions for security filtration on pressure leaf filters (Diastar and Kelly Filters) to fit each specific plant condition. Filter bags and filter covers are perfectly fitted to your equipment, reliably fabricated for unrivalled service life and the best possible filtration performance.
Red mud residue dewatering is one of the major technical and economic challenges in the Bayer process where filtration plays an important role. Sefar is the leading manufacturer of filter media used for red mud management on drum filters and press filters. Together with market leading partners, Sefar has developed a dedicated range, specially adapted to the needs of seed and hydrate filtration. Sefar products are the proven choice for precipitation (fine and coarse Seed Washing) on vacuum disc filters as well as calcination (hydrate washing) on rotary pan and rotary drum filters. Oxalate removal circuits are also served successfully by Sefar filter solutions. A large selection of filter cloths allows an optimal installation, depending on the specific filter requirements.
Base and precious Metal Mining & Refining
Zinc jarosite filtration using Sefar filter belts
Base and precious metals and rare earth (bentonite, bismuth, chromium, cobalt, copper, gold, iridium, lead, manganese, mineral sands, molybdenum, nickel, platinum, palladium, ruthenium, silver, tin, titanium, tungsten, vanadium, zinc, etc) are among the most valuable of earth’s resources and commercial use is increasing rapidly.
The mining and refining as well as the recycling process is carried out in various production steps, where Sefar filter solutions contribute to the specific plant production performance as well as final quality of the refined product thus directly influencing the total cost of ownership (TCO).
Treating and filtering concentrates and residue tailings requires a wide range of filter media to cover the large variety of requirements resulting from the various products and production processes. The main equipment found in these processes are centrifuges, horizontal vacuum belt filters, filter presses, rotary discs and drum filters as well as pressure leaf filters. Sefar is the trusted and reliable source of choice for innovative filter solutions in major mining and refining operations all over the world.
Mineral based fertilizers are a vital component when reacting to the growing population. There is a growing need to feed humans and animals, as well as to support plant and crop growth. The main components of industrial produced fertilizers after granulation are nitrogen (N), phosphorus (P) and potassium (K). Main elements, which are involving Sefar filter solutions are phosphate and potash based fertilizers and their production.
Phosphoric gypsum washing with rotary pan filter using Sefar filter media
Approximately 80% of the phosphoric acid produced globally is used to manufacture mineral based fertilizers.
Phosphoric acid is the base to produce DAP (Diammonium Phosphate), MAP (monoammonium phosphate) and TSP (triple superphosphate), all of which are based on phosphate rock processed via intermediate production of phosphoric acid. This process involves vacuum filtration after the digestion of grinded phosphate rock and sulfuric acid in the reactor. Sefar filter solutions are the material of choice for dewatering the obtained slurry after it is blended with gypsum in order to wash and clarify the phosphoric acid by either the hemihydrate or the dihydrate production process.
The separation process is performed on horizontal vacuum belt filters or with rotary pan filters under harsh chemical and temperature environment. By using Sefar filter solutions, low filter downtime and excellent yield in extracted acid from the gypsum are achieved and through high washing efficiency recovery is maximized. Fluorine content in the process represents also a challenge for most filter media. Sefar has developed a dedicated product offering to match these process conditions and is the supplier of choice to major phosphoric acid production facilities worldwide.
KCI slurry washing and dewatering on HVBF using Sefar filter belt
Potash ores are typically rich in potassium chloride (KCl) and sodium chloride (NaCl) and are typically obtained by evaporation or conventional shaft mining with the extracted ore ground into a powder. The main task during the conversion process from the raw material is to remove impurities such as clay and extract the salts from the potash before crystallization. To achieve this, the solution is washed after flotation and separation of KCI and NaCI. Halit, sylvinite as well as carnallite compounds are removed to obtain the purified potash. The target is to obtain a low, residual cake moisture content in the purified filter cake for the subsequent drying step. Sefar is the leading supplier to the potash producing industry, providing filter solutions for horizontal vacuum belt filters, filter presses and centrifuges in order to ensure a steady and high quality of the final product.
Iron Ore Industry
Horizontal belt filter for iron ore tailings dewatering utilizing Sefar filter belt
The majority of mined iron ore is used to make steel and is found in ore containing hematite and/ or magnetite. The extraction of iron oxide is generally performed through a blasting and removal process from large open pit mines before it is crushed, screened, blended and pelletized for export or local consumption. Pellets are an ideal blast furnace feed because they are hard and of regular size and shape.
Concentration includes all the processes that will increase the iron content of ore by removing impurities. Most iron ore mines employ some form of beneficiation to improve the physical properties of their products (e.g. pelletizing and sintering). Sefar filter media play a major role in the beneficiation and waste management process. The dewatering of iron ore concentrate and iron ore tailings is performed on rotary (hyperbaric) disc filters, horizontal vacuum belt filters, rotary drum filters and/or filter presses.
Three important parameters are remarkably improved by using Sefar filter solutions:
Consistency of cake moisture of around 9 – 10%
Cake discharge properties
Service life of filter media
Sefar filter solutions are closely developed in cooperation with leading OEMs and are the proven solution for major pelletizing plants all over the world.
Tailings and Waste Management
Red mud residue tailing treatment with Sefar filter press cloths
The refining of base and precious metals as well as industrial minerals leaves a remarkable amount of residues after the extraction. Traditional tailings storage dams/ ponds continue to fail on a relatively regular basis. To eliminate the risk of tailings dam failures from and to minimize the footprint in our environment, there is a clear trend for dry stacking to backfill the mining sites instead of paste tailings facilities and large settling ponds.
Treated and filtered tailings are becoming an increasingly common consideration for residue management at many mining sites. As the need for dry stacked tailings is increasing, so has the need for large dewatering equipment to manage the large volume of tailings to be treated.
This trend also replaces rotary drum filters and rotary disc filters for tailings treatment. The major equipment being able to fulfill these requirements are filter presses. Sefar is working together with major OEMs and refineries to address this topic and to further improve the filter cloth performance in terms of lifetime and productivity. This will contribute to plant efficiency, reduce press downtime and meet health and safety standards set by the refineries.
Waste water treatment in the plant and corresponding filtration technology is a task, where Sefar is the capable partner of choice to improve waste water treatment filter efficiency. With the target in mind, to consume only minimal clean water resources and the potential to create sustainable filtration solutions together with the end user, Sefar application specialists support the specific needs of the refineries to improve the filter media performance in this process step which is carried out on filter presses or centrifuges.
Titanium Dioxide Industry
Micronizer Bag House operating pleated elements of Sefar
There are two main methods of manufacturing titanium dioxide: The traditional, less environmentally friendly sulfate method and the newer, more technologically advanced chloride process. Sulfate process consists of black section with sulfation, clarification, crystallization, hydrolysis and vacuum filtration stages and the white section with wet milling, leaching, surface treatment, washing, drying, micronizing and packaging sections. Two crystalline forms of titanium dioxide can be produced using sulfate process i.e. anatase and rutile. Chloride process on the other hand consists of rutile ore chlorination, condensation, gas scrubbing, purification, oxidation followed by the stages common from this point.
Still the most common process for titanium dioxide production is the sulfate process where Sefar filter solutions play an important role. A carefully controlled blend of ilmenite and slag is mixed with highly concentrated sulfuric acid to digest the TiO2-containing feedstock to so called 'upgraded slag'. The pre-processes of sludge treatment and preparation involve either filter presses, rotary drum filters or horizontal vacuum belt filters. Sefar has developed a dedicated range of filter media in order to maximize the filter equipment performance. The clarified liquor is separated from the solution by flocculation (decantation) and filtration. The clarified liquor is then hydrolyzed with steam in order to precipitate hydrated titanium. Vacuum leaf filters (mostly Moore Filters) separate the precipitated hydrated TiO2 from the mother liquor. Best clarification results are obtained by using Sefar filter solutions for vacuum leaf filters. Obtained TiO2 pulp ex vacuum filters (mostly Moore Filters) is dewatered and dosed with crystallization promoting chemicals and then calcined in rotary kilns in temperatures of around 1000 °C to form the required crystalline, either rutile or anatase,TiO2 form. Calcined discharge is ground, coated with oxides washed using rotary drum filters, dried and finally milled ('micronized') and TiO2 pigment is separated from superheated steam in bag house filters. High temperature Sefar X-600 pleated elements designed for micronizing bag houses are the industries` preferred solution and have proven their advantages (increased surface area at best emission values) compared to conventional filter bags of any type in various TiO2 production plants worldwide.
Sefar Filter Solutions for OEM
Our products meet the specific needs of these filtration applications and are successfully running all over the world on all known equipment brands and OEMs, such as:
Fraccaroli e Balzan
Vacuum Belt Filters
Sefar has pioneered the DLW technology, combining two different filter media layers – SEFAR TETEX DLW is setting the performance benchmark in mineral processing.
Sefar has extensive experience in mineral concentrate and tailings management and offers ready-made filter cloths adapted to fit customer 's requirements.
Rotary Drum Filters
Sefar’s innovative synthetic fabric is the material for rotary drum filters. Sefar filter belt and cover solutions offer excellent separation efficiency and a long, trouble-free lifetime.
Rotary Disc Filters
The Sefar offer includes ready to use, easy to install and perfectly fitting disc filter segment covers for vacuum and hyperbaric operated rotary disc filters.
Rotary Pan Filters
Sefar filter covers are suitable for all common types of rotary pan filters such as tilitng pan or screw discharge systems.
Sefar filter bags for Diastar and Kelly filters show a unique performance in alumina pregnant liquor clarification – they are known to last longer & yield higher results.
Bag House Filters
Our pleated elements for bag house filters offer an increased filtration area and provide an improved filtration efficiency compared to conventional filter bags.
Sefar offers innovative filter solutions for centrifuges in the mineral industry. Applications are found in base and precious ore processing and coal washing.