Ash, sawdust

Dust. Relatively large particles about 100 xm in diameter that come directly from substances being used (e.g., coal dust, ash, sawdust, cement dust, grain dust). 

Pulverised fuel ash, sawdust, spent lime and many other waste products can and have been used in some apphcations usually where a rou separation is required. Other eciahy prepared solid powder materials such as hydrated magneaum silicate, hydrated calcium silicate, bentonite, fuller s earth, or activated carbon are used in some applications piinc ally because of their adsorptive properties but they may also act as a filter aid in the separation of the particulate solids fi om the liquid. 

Cellulose acetate Silica gel Scoured wool Sawdust Rayon waste Fluorspar Tapioca Breakfast food Asbestos fiber Cotton linters Rayon staple Starch Aluminum hydrate Kaolin Cryolite Lead arsenate Cornstarch Cellulose acetate Dye intermediates Calcium carbonate White lead Lithopone Titanium dioxide Magnesium carbonate Aluminum stearate Zinc stearate Lithopone Zinc yellow Calcium carbonate Magnesium carbonate Soap flakes Soda ash Cornstarch Synthetic rubber... 

Charcoal is not only employed in activated form for decoloring and adsorbing dissolved admixtures but also in its unactivated form as a filter aid. It can be used in suspensions consisting of aggressive liquids (e.g., strong acids and alkalies). As with sawdust, it can be used to separate solids that may be roasted. On combustion, the charcoal leaves a residue of roughly 2 percent ash. Particles of charcoal are porous and form cakes of high density but that have a lesser retention ability than does diatomite. 

Wood ashes.—The ash of wood, not coal, contains about 30 per cent, of potassium carbonate. Prior to the exploitation of the Stassfurt salts about the middle of the nineteenth century, the chief source of potash was wood ashes, and the process is still used in certain localities where wood-fuel is employed and where much waste wood is available—e.g. in some parts of Canada, United States, Russia, Spain, etc. The ash of trees, hedge-cuttings, sawdust, etc., can be made to yield potash.5 In the Caucasus, the sunflower is grown on waste land for the sake of its seed. The stalks, leaves, etc., are a by-product and are burnt the ash is used as a source of potash. Nearly 7000 tons per annum of crude potash from this source were exported from Novorossik in Russia. The residues in the manufacture of olive oil and almond shells are also stated by G. l Abate to be exceptionally rich in potash salts F. W. F. Day claims that the roots of the water hyacinth (eiehornia crassipes) have... 

The ash is mixed with 5 to 10 per cent, of slaked lime and placed in wooden barrels with false bottoms. Hot water is poured over the mixture, and, after standing for some time, the liquid is drawn off from time to time by removing a plug near the bottom of the cask. The liquid with a sp. gr. over 1 -15 is evaporated the low sp. gr. liquor may be used for lixiviating more ash and the residue in the barrels may be used as manure. The evaporation of the densest liquor to dryness is conducted in cast-iron pots, and the residue is afterwards calcined in a reverberatory furnace to burn away the organic matter—at the same time sulphates may be converted into sulphides. The product is crude potash. The crude potash may be mixed with sawdust and re-calcined. It is then digested with twice its weight of hot water, filtered, and cooled. The less soluble impurities—mainly potassium sulphate—crystallize out, and finally the mother liquid is evaporated to dryness and calcined as before, - or the solu. may be evaporated until crystals of potassium carbonate are deposited. 

The other method. of conducting the evaporation of vat liqiiors is by means of iron pans, with the fire and, heated air applied beneath. These—named fishing pans —are of considerable size, and shaped somewhat similar to a boat. They may bo heatad by a fire used solely for the purpose in which case to prevent injury to the pan, the arch of the furnace should be continued for some distance beneath, or the pan may be placed at the end of the black-ash furnace farthest from the fire, just as with the salting pan, except that the heated air is mads to pass under instead of over the pan. The evaporation is rapidly conducted by this method and when the lie becomes concentrated to a certain strength, small crystals of mo nob yd rated carbonate of soda— Na 0, COa, HO—constantly fall to the bottom, and as quickly as thoy fall are raked together to tho end of the pan farthest from the source of heat, and then Scooped or fished out by moans of perforated iron shovels. After being allowed some time to draiD, the salta so obtained are washed with fresh vat liquor, and then removed a reverberatory furnace, and all worked about until sufficiently dry. The deep-red mother liquor is either applied to the production of caustic soda or evaporated, and the residue heated with sawdust as before directed. 

Shown below are the N-P-K ratings for three fertilizer additives sawdust, fish meal, and wood ashes. Using what you know about the chemical composition of these substances, assign each to its most likely N-P-K rating. 

Salts, sawdust, scrap metals, shales, silicates, soda ash, sodium chloride, sodium compounds, sodium cyanide, sponge iron, steel turnings, stone wool, sugar, sulfur Teas, tin, titanium sponge, turnings Urea, urea formaldehyde Vanadium, vermiculite, vitamins Waxes, welding powder, wood dust, wood shavings Yeast (dry)... 

Bulking of liquid wastes. Liquid wastes are prohibited from landfills. Wastes with free liquids are mixed with a bulking agent such as dry sawdust, cement kiln dust, or fly ash. 

Sand, slUca coarM dry Sand very nne. dry Sawdust, dry Soda ash, light soybean meal Starch, lump Starch, pulverised ... 

The heating value depends on the moisture and ash contents of the densified material and is usually in the range of 15 to 17 MJ/kg. The use of asphaltic binders or pelletizing conditions that result in some carbonization can yield densified products that have higher heating values. Pellets, briquettes, and logs have been manufactured by densification methods from biomass for many years. Prestologs made from waste wood and sawdust were marketed before 1940 in North America, and the market for pellet fuels made from wood... 

Fuel panicle size and excess air also affect the extent of combustion as more unbumt carbon in the bottom and fly (cyclone) ash was derived from combustion of the off-cuts with sawdust (RPO) and E. nitens steam treated (ENT), both of which involved more fine (or fibre) particles and lower excess air. 

Pyrolysis of the wastes promotes pronounced changes in chemical compositions, as reflected in the results obtained for the char samples diat are strongly dependent on each waste. Release of volatile matter leads to enhance the inotganic material of the samples, the char from AA sawdust showing the highest ash content (Table 2). All the wastes are enriched as fuels during pyrolysis. Increases in %C and decreases in %0 may be... 

The ash content of char samples is another feature that has to be taken into account since activated carbons with low ash contents are normally desired. The low ash content of the olive stone-char should be emphasised. From this viewpoint, the relatively higher ash content of the AA-char compared to char samples from peanut husks and PD sawdust is disadvantageous. 

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