Moisture content acidity

A nickel laterite from Piaui, Brazil was used in this study. The top size of the ore was limited to 12.5 mm. The nickel laterite was composed mainly of quartz, silico-femiginous plasma, and clay minerals. The nickel content is 0.9%. The main nickel-bearing minerals are chlorite, smectite, vermiculite, manganese oxide and silico-ferruginous plasma [6]. Since moisture content, acid concentration, retention time and drum rotation speed are operating factors in drum agglomeration, they were investigated in this study. 

The effects of moisture content, acid concentration, drum rotation speed and mixing time on the agglomerate size distribution of the nickel laterite were studied. In the agglomerate size distribution figures, the legends have the form of A B C. A represents the moisture content in wt while B represents the acid solution concentration (g/L). Finally, C represents special conditions for example NC is for drum critical speeds and min is for mixing times in minutes. 

Adipic acid is shipped in quantities ranging from 22.7 kg (50-lb bags) to 90.9 t (200,000-lb hopper cars). Upon long standing, the soHd material tends to cake, dependent on such factors as initial particle size and moisture content. Shipping data in the United States are "Adipic Acid," DOT-ID ALT 9077, DOT Hazard Class ORM-E. It is regulated only in packages of 2.3 t (5,000 lb) or more (hopper cars and pressure-differential cars and tmcks) (157). 

Properties. Important properties of NSP are free acid content, as H2SO4, 1—2% moisture content, 5—8% P2O5 soluble, in neutral citrate... 

The precipitated cellulose acetate is filtered from the dilute (25—36%) acetic acid. The acetic acid and salts remaining from the sulfuric acid neutrali2ation are removed by washing. The wet polymer is typically dried to a moisture content of 1—5%. The dilute acetic acid obtained from the washing and precipitation steps caimot be used in other stages of the process. Its efficient recovery and recycle are an economic necessity. 

The products of reaction are pumped to a filter press for separation into a sodium sulfate solution and a filter cake having a low moisture content. The filter cake is then ready to be processed for the recovery of lead. The filtrate from the process contains an excess of sodium carbonate, and can be neutralized using the sulfuric acid drained from the batteries. 

Commercial cmde lecithin is a brown to light yeUow fatty substance with a Hquid to plastic consistency. Its density is 0.97 g/mL (Uquid) and 0.5 g/mL (granule). The color is dependent on its origin, process conditions, and whether it is unbleached, bleached, or filtered. Its consistency is deterrnined chiefly by its oil, free fatty acid, and moisture content. Properly refined lecithin has practically no odor and has a bland taste. It is soluble in aflphatic and aromatic hydrocarbons, including the halogenated hydrocarbons however, it is only partially soluble in aflphatic alcohols (Table 5). Pure phosphatidylcholine is soluble in ethanol. 

Other Measurements. Other tests include free moisture content, rate of dissolution and undissolved residue in acids and alkaH, resin and plasticizer absorption, suspension viscosity, and specific surface area. Test procedures for these properties are developed to satisfy appHcation-related specifications. 

The moisture content of cmde sulfur is determined by the differential weight of a known sample before and after drying at about 110°C. Acid content is determined by volumetric titration with a standard base. Nonvolatile impurities or ash are determined by burning the sulfur from a known sample and igniting the residue to remove the residual carbon and other volatiles. 

Pan and cascade burners are generally more limited ia flexibiHty and are useful only where low sulfur dioxide concentrations are desired. Gases from sulfur burners also contain small amounts of sulfur trioxide, hence the moisture content of the air used can be important ia achieving a corrosion-free operation. Continuous operation at temperatures above the condensation poiat of the product gases is advisable where exposure to steel (qv) surfaces is iavolved. Pressure atomiziag-spray burners, which are particularly suitable when high capacities are needed, are offered by the designers of sulfuric acid plants. 

Liquid sulfur dioxide discolors iron, copper, and brass at ca 300 ppm moisture and produces light scale at ca 0.1 wt % moisture and serious corrosion at ca 0.2 wt % or higher moisture content. Copper and brass can be used to handle wet sulfur dioxide where some corrosion can be tolerated, or where the moisture level is low. Wooden tanks are widely used for sulfurous acid preparation, handling, and storage. Sulfite pulp digestors are made of steel lined with acid-resistant brick. 

Small amounts of sulfuric acid mist or aerosol are always formed in sulfuric acid plants whenever gas streams are cooled, or SO and H2O react, below the sulfuric acid dew point. The dew point varies with gas composition and pressure but typically is 80—170°C. Higher and lower dew point temperatures are possible depending on the SO concentration and moisture content of the gas. Such mists are objectionable because of both corrosion in the process and stack emissions. 

Solubility. One of PVP s more outstanding attributes is its solubility in both water and a variety of organic solvents. PVP is soluble in alcohols, acids, ethyl lactate, chlorinated hydrocarbons, amines, glycols, lactams, and nitroparaffins. SolubiUty means a minimum of 10 wt % PVP dissolves at room temperature (moisture content of PVP can influence solubiUty). PVP is insoluble in hydrocarbons, ethers, ethyl acetate, j -butyl-4-acetate, 2-butanone, acetone, cyclohexanone, and chlorobenzene. Both solvent polarity and H-bonding strongly influence solubiUty (77). 

Methylene chloride is one of the more stable of the chlorinated hydrocarbon solvents. Its initial thermal degradation temperature is 120°C in dry air (1). This temperature decreases as the moisture content increases. The reaction produces mainly HCl with trace amounts of phosgene. Decomposition under these conditions can be inhibited by the addition of small quantities (0.0001—1.0%) of phenoHc compounds, eg, phenol, hydroquinone, -cresol, resorcinol, thymol, and 1-naphthol (2). Stabilization may also be effected by the addition of small amounts of amines (3) or a mixture of nitromethane and 1,4-dioxane. The latter diminishes attack on aluminum and inhibits kon-catalyzed reactions of methylene chloride (4). The addition of small amounts of epoxides can also inhibit aluminum reactions catalyzed by iron (5). On prolonged contact with water, methylene chloride hydrolyzes very slowly, forming HCl as the primary product. On prolonged heating with water in a sealed vessel at 140—170°C, methylene chloride yields formaldehyde and hydrochloric acid as shown by the following equation (6). 

More recendy, the molten caustic leaching (MCL) process developed by TRW, Inc. has received attention (28,31,32). This process is illustrated in Eigure 6. A coal is fed to a rotary kiln to convert both the mineral matter and the sulfur into water- or acid-soluble compounds. The coal cake discharged from the kiln is washed first with water and then with dilute sulfuric acid solution countercurrendy. The efduent is treated with lime to precipitate out calcium sulfate, iron hydroxide, and sodium—iron hydroxy sulfate. The MCL process can typically produce ultraclean coal having 0.4 to 0.7% sulfur, 0.1 to 0.65% ash, and 25.5 to 14.8 MJ/kg (6100—3500 kcal/kg) from a high sulfur, ie, 4 wt % sulfur and ca 11 wt % ash, coal. The moisture content of the product coal varies from 10 to 50%. 

Equilibrium moisture content of a hygroscopic material may be determined in a number of ways, the only requirement being a source of constant-temperature and constant-humidity air. Determination may be made under static or dynamic conditions, although the latter case is preferred. A simple static procedure is to place a number of samples in ordinaiy laboratoiy desiccators containing sulfuric acid solutions of known concentrations which produce atmospheres of known relative humidity. The sample in each desiccator is weighed periodically until a constant weight is obtained. Moisture content at this final weight represents the equilibrium moisture content for the particular conditions. 

A samphng probe is placed at any location in the stack, and a grab sample is collected in an evacuated flask. This flask contains a solution of siilfiiric acid and hydrogen peroxide, which reacts with the NO. The volume and moisture content of the exhaust-gas stream must be determined for calculation of the total mass-emission rate. The sample is sent to a laboratoiy, where the concentration of nitrogen oxides, except nitrons oxide, is determined colorimetrically. 

The failure was caused by sulfuric acid containing excessive water. Nearly pure sulfuric acid is only very mildly corrosive. However, when moisture content approaches 20% at 100°F (38°C), corrosion rates on 304... 

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