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Superior replacement crusher parts are taken from the same warehouse used for our manufacturing operations. That means you get an equal part, with equal quality, thats designed exactly for your machine.
Aggregate materials that are processed through a washing cycle are stripped of any unwanted silts or clays to meet specification. This deleterious or unwanted material in your virgin aggregate may also include natural earthly debris like shale, coal, roots, twigs and/or soft stones.
Silica sand low in iron is much in demand for glass, ceramic and pottery use, and for many of these applications clean, white sand is desired. Impurities such as clay slime, iron stain, and heavy minerals including iron oxides, garnet, chromite, zircon, and other accessory minerals must not be present. Chromium, for example, must not be present, even in extremely small amounts, in order for the sand to be acceptable to certain markets. Feldspars and mica are also objectionable. Generally, iron content must be reduced to 0.030% Fe2O3 or less.
Silica sand for making glass, pottery and ceramics must meet rigid specifications and generally standard washing schemes are inadequate for meeting these requirements. Sand for the glass industry must contain not more than 0.03% Fe2O3. Concentrating tables will remove free iron particles but iron stained and middling particles escape gravity methods. Flotation has been very successfully applied in the industry for making very low iron glass sand suitable even for optical requirements.Sub-A Flotation Machines are extensively used in this industry for they give the selectivity desired and are constructed to withstand the corrosive pulp conditions normally encountered (acid circuits) and also the abrasive action of the coarse, granular, slime free washed sand.
The flowsheet illustrates the more common methods of sand beneficiation. Silica may be obtained from sandstone, dry sand deposits and wet sand deposits. Special materials handling methods are applicable in each case.
The silica bearing sandstone must be mined or quarried much in the manner for handling hard rock. The mined ore is reduced by a Jaw Crusher to about 1 size for the average small tonnage operation. For larger scale operations two-stage crushing is advisable.
The crushed ore is reduced to natural sand grain size by Rod Milling. Generally, one pass treatment through the Rod Mill is sufficient. Grinding is done wet at dilutions in excess of normal grinding practice. A Spiral Screen fitted to the mill discharge removes the plus 20 mesh oversize which either goes to waste or is conveyed back to the mill feed for retreatment.
Sand from such deposits is generally loaded into trucks and transported dry to the mill receiving bin. It is then fed on to a vibrating screen with sufficient water to wash the sand through the 20 mesh stainless screen cloth. Water sprays further wash the oversize which goes to waste or for other use. The minus 20 mesh is the product going to further treatment.
The sand and water slurry for one of the three fore-mentioned methods is classified or dewatered. This may be conveniently done by cyclones or by mechanical dewatering classifiers such as the drag, screw, or rake classifiers.
From classification the sand, at 70 to 75% solids, is introduced into a Attrition Scrubber for removal of surface stain from the sand grains. This is done by actual rubbing of the wet sand grains, one against another, in an intensely agitated high density pulp. Most of the work is done among the sand grains not against the rotating propellers.
For this service rubber covered turbine type propellers of special design and pitch are used. Peripheral speed is relatively low, but it is necessary to introduce sufficient power to keep the entire mass in violent movement without any lost motion or splash. The degree of surface filming and iron oxide stain will determine the retention time required in the Scrubber.
The scrubbed sand from the Attrition Machine is diluted with water to 25-30% solids and pumped to a second set of cyclones for further desliming and removal of slimes released in the scrubber. In some cases the sand at this point is down to the required iron oxide specifications by scrubbing only. In this case, the cyclone or classifier sand product becomes final product.
Deslimed sand containing mica, feldspar, and iron bearing heavy minerals can be successfully cleaned to specifications by Sub-A Flotation. Generally this is done in an acid pulp circuit. Conditioning with H2SO4 and iron promoting reagents is most effective at high density, 70-75% solids. To minimize conditioning and assure proper reagentizing a two-stage Heavy Duty Open Conditioner with Rubber Covered Turbine Propellers is used. This unit has two tanks and mechanisms driven from one motor.
The conditioned pulp is diluted with water to 25-30% solids and fed to a Sub-A Flotation Machine especially designed for handling the abrasive, slime free sand. Acid proof construction in most cases is necessary as the pulps may be corrosive from the presence of sulfuric acid. A pH of 2.5-3.0 is common. Wood construction with molded rubber and 304 or 316 stainless steel are the usual materials of construction. In the flotation step the impurity minerals are floated off in a froth product which is diverted to waste. The clean, contaminent-free silica sand discharges from the end of the machine.
The flotation tailing product at 25 to 30% solids contains the clean silica sand. A SRL Pump delivers it to a Dewatering Classifier for final dewatering. A mechanical classifier is generally preferable for this step as the sand can be dewatered down to 15 to 20% moisture content for belt conveying to stock pile or drainage bins. In some cases the sand is pumped directly to drainage bins but in such cases it would be preferable to place a cyclone in the circuit to eliminate the bulk of the water. Sand filters of top feed or horizontal pan design may also be used for more complete water removal on a continuous basis.
Dry grinding to minus 100 or minus 200 mesh is done in Mills with silica or ceramic lining and using flint pebbles or high density ceramic or porcelain balls. This avoids any iron contamination from the grinding media.
In some cases it may be necessary to place high intensity magnetic separators in the circuit ahead of the grinding mill to remove last traces of iron which may escape removal in the wet treatment scrubbing and flotation steps. Iron scale and foreign iron particles are also removed by the magnetic separator.
In general most silica sands can be beneficiated to acceptable specifications by the flowsheet illustrated. Reagent cost for flotation is low, being in the order of 5 to 10 cents per ton of sand treated. If feldspars and mica must also be removed, reagent costs may approach a maximum of 50 cents per ton.
Laboratory test work is advisable to determine the exact treatment steps necessary. Often, attrition scrubbing and desliming will produce very low iron silica sand suitable for the glass trade. Complete batch and pilot plant test facilities are available to test your sand and determine the exact size of equipment required and the most economical reagent combinations.
Silica sand for making glass, pottery and ceramics must meet rigid specifications and generally standard washing schemes are inadequate for meeting these requirements. Sand for the glass industry must contain not more than 0.03% Fe2O3. Concentrating tables will remove free iron particles but iron stained and middling particles escape gravity methods. Flotation has been very successfully applied in the industry for making very low iron glass sand suitable even for optical requirements.
Sub-A Flotation Machines are extensively used in this industry for they give the selectivity desired and are constructed to withstand the corrosive pulp conditions normally encountered (acid circuits) and also the abrasive action of the coarse, granular, slime free washed sand.
The flowsheet illustrated is typical for production of glasssand by flotation. Generally large tonnages are treated, forexample, 30 to 60 tons per hour. Most sand deposits can be handled by means of a dredge and the sand pumped to the treatment plant. Sandstone deposits are also being treated and may require elaborate mining methods, aerial tramways, crushers, and wet grinding. Rod Mills with grate discharges serve for wet grinding to reduce the crushed sandstone to the particle size before the sand grains were cementedtogether in the deposit. Rod milling is replacing the older conventional grinding systems such as edge runner wet mills or Chilean type mills.
Silica sand pumped from the pit is passed over a screen, either stationary, revolving or vibrating type, to remove tramp oversize. The screen undersize is washed and dewatered generally in a spiral type classifier. Sometimes cone, centrifugal and rake type classifiers may also be used for this service. To clean the sand grains it may be necessary to thoroughly scrub the sand in a heavy-duty sand scrubber similar to the Heavy-duty Agitator used for foundry sand scrubbing. This unit is placed ahead of the washing and dewatering step when required. The overflow from the classifier containing the excess water and slimes is considered a waste product. Thickening of the wastes for water reclamation and tailings disposal in some areas may be necessary.
The washed and dewatered sand from the spiral-type classifier is conveyed to a storage bin ahead of the flotation section. It is very important to provide a steady feed to flotation as dilution, reagents and time control determines the efficiency of the process.
Feeding wet sand out of a storage bin at a uniform rate presents a materials handling problem. In some cases the sand can be uniformly fed by means of a belt or vibrating-type feeder. Vibrators on the storage bin may also be necessary to insure uniform movement of the sand to the feeder. In some cases the wet sand is removed from the bin by hydraulic means and pumped to a spiral-type classifier for further dewatering before being conveyed to the next step in the flowsheet.
Conditioning of the sand with reagents is the most critical step in the process. Generally, for greater efficiency, it is necessary to condition at maximum density. It is for this reason the sand must be delivered to the agitators or conditioners with a minimum amount of moisture. High density conditioning at 70 to 75% solids is usually necessary for efficient reagentizing of the impurity minerals so they will float readily when introduced into the flotation machine.
The Heavy-duty Duplex Open-type Conditioner previously developed for phosphate, feldspar, ilmenite, and other non-metallic mineral flotation is ideal for this application. A duplex unit is necessary to provide the proper contact time. Circular wood tanks are used to withstand the acid pulp conditions and the conditioner shafts and propellers are rubber covered for both the abrasive and corrosive action of the sand and reagents.
Reagents are added to the conditioners, part to the first and the balance to the second tank of the duplex unit, generally for flotation of impurities from silica sand. These reagents are fuel oil, sulphuric acid, pine oil, and a petroleum sulfonate. This is on the basis that the impurities are primarily oxides. If iron is present in sulphide form, then a xanthate reagent is necessary to properly activate and float it. The pulp is usually regulated with sulfuric acid to give a pH of 2.5-3.0 for best results through flotation.
A low reagent cost is necessary because of the low value of the clean sand product. It is also necessary to select a combination of reagents which will float a minimum amount of sand in the impurity product. It is desirable to keep the weight recovery in the clean sand product over 95%. Fatty acid reagents and some of the amines have a tendency to float too much of the sand along with the impurities and are therefore usually avoided.
After proper reagentizing at 70 to 75% solids the pulp is diluted to 25 to 30% solids and introduced into the flotation machine for removal of impurities in the froth product. Thepulp is acid, pH 2 .5 to 3.0 and the sand, being granular and slime free, is rapid settling so a definite handling problem is encountered through flotation.
The Sub-A Flotation Machine has been very successful for silica sand flotation because it will efficiently handle the fast settling sand and move it along from cell to cell positively. Aeration, agitation and selectivity due to the quiet upper zone can be carefully regulated to produce the desired separation. The machine is constructed with a wood tank and molded rubber wearing parts to withstand the corrosive action of the acid pulp. Molded rubber conical-type impellers are preferred for this service when handling a coarse, granular, abrasive sand.
Flotation contact time for removal of impurities is usually short. A 4, and preferably a 6 cell, machine is advisable. Cell to cell pulp level control is also desirable. A 6 cell No. 24 (43 x 43) Sub-A Flotation Machine in most cases is adequate for handling 25 to 30 tons of sand per hour. If the impurities are in sulphide form a standard machine with steel tank and molded rubber parts is adequate provided the pulp is not acid. Otherwise acid proof construction is essential.
The flotation tailing product is the clean sand discharging from the end of the flotation machine at 25 to 30% solids and must be dewatered before further processing. Dewatering can be accomplished in a dewatering classifier and then sent to storage or drying. Top feed or horizontal vacuum filters are often used to remove moisture ahead of the dryer. Dry grinding of the sand to meet market requirements for ceramic and pottery use is also a part of the flowsheet in certain cases.
This particular sand was all minus 20 mesh with only a trace minus 200 mesh and 70% plus 65 mesh. Iron impurity was present as oxide and stained silica grains. The plant which was installed as a result of this test work is consistently making over a 95% weight recovery and a product with not over 0.02% Fe2O3 which at times goes as low as 0.01% Fe2O3.
Si02, minimum..99.8 per cent Al2O3, maximum..0.1 percent Fe2O3, maximum..0.02 per cent CaO + MgO, maximum.0.1 percent For certain markets, a maximum of 0.030 per cent Fe2O3 is acceptable.
Natural silica-sand deposits generally contain impurityminerals such as clay, mica, and iron oxide and heavy iron minerals which are not sufficiently removed by washing and gravity concentration. Flotation is often used to remove these impurity minerals to meet market specifications.
Anionic-type reagents, such as fatty acids, are used to float some impurities in alkaline pulp. Cationic-type reagents such as amines or amine acetates are also used with inhibitors such as sulphuric or hydrofluoric acids to float certain impurity minerals and depress the silica.
McLanahan Sand Washing Plants process sand from its raw state into products that meet various specifications. The process requirements vary depending on the input and desired output, but plants typically scrub, liberate, deslime, wash, classify, decontaminate and dewater the sand, as well as process the effluent stream that results.
For customers who are interested in maximizing yield and producing precisely graded products to the end-user's needs and specifications, it is more likely that a custom sand plant is the correct solution. Whether the sands are natural or manufactured, fine or coarse, well or poorly graded, or required for specialty applications, McLanahan can offer a plant specifically designed to suit your needs.
McLanahan is best known for creating process solutions to address the specific needs of each customer's application. We have one of the largest ranges of robust, field-proven equipment, and we are constantly innovating. Our background and expertise in applications is second to none.
Depending on the application, McLanahan can perform lab scale tests on materials, including sieve analysis, percent solids, attrition scrubbing, sink/float, sand equivalency and durability, Hydrosizer based classification, static and dynamic flocculation/settling and Filter Press testing.
With our proprietary simulations, in-house lab and industry expertise, you get a plant designed specifically for your site with capacities to match your need. Our expertise is the envy of the industry, so when you couple this with one of the largest ranges of equipment offerings, we can offer a solution.
Sand Washing comes in many forms and covers a range of feed and products produced, including construction aggregates such as concrete, asphalt, mason, mortar, and plaster sands; sports sands such as for golf courses, ball parks, and race courses; industrial sands, such as glass, filter, foundry, and frac; specialty sands and materials such as anti-skid, roofing granules; deligniting/organics removal; and soils washing for environmental projects.
First, consider the following questions: What do you have? What do you want to make? If the answer is a very specialized gradation and a difficult natural sand deposit, then consider a Recipe Plant. If the answer is a manufactured sand and you are making concrete sand all day every day, then an Ultra Sand Plant or Modular Wash Plant may be your answer.
Many other factors, such as available investment, local competition and expanding markets, will influence this decision. Through a process of elimination starting with the simplest configuration, McLanahans experienced personnel will guide you through to the best options.
Ultra Sand Plants, which utilize Dewatering Screens, Pumps and Cyclones, offer greater separation efficiency and provide a higher product yield that can be reused almost immediately due to the effectiveness of the Dewatering Screen. Ultra Sand Plants are commonly used to wash and dewater industrial and specialty sands, as well as asphalt, concrete and masonry sands.
For high-quality sand that meets strict specifications, look no further than McLanahan Recipe Sand Plants. These sand plants make use of every grain of sand to offer customized blending for concrete, foundry, glass and plaster sands. The resulting sand product is consistent, uniform and will meet even the tightest of specifications.
McLanahan In-Line Blending Sand Plants provide high product yields, offer flexible blending options, produce drier products and improve product consistency. They are simple to operate, create accurate splits and are field-proven.
McLanahan designs each of its Frac Sand Plants to meet the specific needs of each customer. Using field-proven McLanahan equipment, Frac Sand Plants can be designed for classifying, desliming, dewatering, pumping, scrubbing, sizing, tailings management and waste solids management. McLanahan Frac Sand Plants are engineered to make the critical separations required for frac sand. They produce the highest product yield at the lowest moisture.
Classifying Tank Based Sand Plants can create multiple products from a single feed as well as remove slimes and excess water. Feed material enters the Sand Classifying Tank first, and sand grains settle in sections according to size down the length of the tank. Valves at the bottom of each section release the grains into one of several flumes used to create a primary, secondary or tertiary product, depending on the application. The discharged products are then dewatered by Dewatering Screens and/or Fine Material Screw Washers. The addition of Cyclones and/or rising current water can be used to deslime the feed.
McLanahan Industrial Sand Plants are designed with a combination of McLanahan equipment to provide extremely sharp classification of various industrial sands. This equipment can include Attrition Cells, Dewatering Screens, Hydrocyclones, Hydrosizers, Filter Presses, Fine Material Screw Washers, Pumps, Separators and Thickeners.
Although Portable Plants, which can be wheel-mounted or skid-based to provide an ease of transport, are limited in capacity, they do not limit the process. Portable Sand Plants can be used for classifying, dewatering, sizing and removing oversize and organics from feeds to produce aggregates, construction and demolition materials, and specialty sands.
McLanahan Ultra Fines Recovery Plants can recover +400 mesh material for use in many industries. UFRs are especially well-suited in the aggregates industry for effluent streams containing <100 mesh fractions and for recovering valuable coal from effluent streams in the coal industry.
This is why we created a range of machines for the washing of aggregates. Brining customers the opportunity to manage the whole process with a single supply point, guaranteeing the best output both from the washing system and the water treatment plants.
The growing demand for silica sands in varous sectors and the increased requirement for very tight gradation capablity alongside maximum removal of contaminants underline the need for a project based approach to supply
Recycling, C&D recycling especially, is a fast-pace growing sector. The concern for re-using materials to respect the environment and comply with laws has led to a development of technologies, systems and plants to which Matec bring significant experience. In addition, the recovery of resources has always been one of the key objective of our business since we started as Matec back in 2003.
Matec is already a leader in the water management system with over 3000 installations which help customer save and recover water all across the world. Through our filterpresses and our thickeners, you will be able to reuse up to 95% of the water. Cutting down costs is essential for a washing system and our equipment will deliver it, maximizing the return of your plant.