Sulfates industrial processes

Many industrial processes involve a chemical reaction between two Hquid phases, for example nitration (qv), sulfonation (see Sulfonation and sulfation), alkylation (qv), and saponification. These processes are not always considered to be extractions because the main objective is a new chemical product, rather than separation (30). However these processes have many features in common with extraction, for example the need to maintain a high interfacial area with the aid of agitation and the importance of efficient phase separation after the reaction is completed. 

There are numerous variations of the wet process, but all involve an initial step in which the ore is solubilized in sulfuric acid, or, in a few special instances, in some other acid. Because of this requirement for sulfuric acid, it is obvious that sulfur is a raw material of considerable importance to the fertilizer industry. The acid—rock reaction results in formation of phosphoric acid and the precipitation of calcium sulfate. The second principal step in the wet processes is filtration to separate the phosphoric acid from the precipitated calcium sulfate. Wet-process phosphoric acid (WPA) is much less pure than electric furnace acid, but for most fertilizer production the impurities, such as iron, aluminum, and magnesium, are not objectionable and actually contribute to improved physical condition of the finished fertilizer (35). Impurities also furnish some micronutrient fertilizer elements. 

Terpenes, specifically monoterpenes, are naturally occurring monomers that are usually obtained as by-products of the paper and citms industries. Monoterpenes that are typically employed in hydrocarbon resins are shown in Figure 2. Optically active tf-limonene is obtained from various natural oils, particularly citms oils (81). a and P-pinenes are obtained from sulfate turpentine produced in the kraft (sulfate) pulping process. Southeastern U.S. sulfate turpentine contains approximately 60—70 wt % a-pinene and 20—25 wt % P-pinene (see Terpenoids). Dipentene, which is a complex mixture of if,/-Hmonene, a- and P-pheUandrene, a- and y-terpinene, and terpinolene, is also obtained from the processing of sulfate Hquor (82). 

The most commonly used reinforcement for high pressure decorative and industrial laminates is paper (qv). The strong substrate layers, or filler, are kraft paper. Kraft is a brown paper made from a sulfate pulp process (8). It consists of both short cellulose fibers from hardwoods and long fibers from conifers. The long fibers impart most of the wet strength required for resin saturation processes. 

Lithium Carbonate. Lithium carbonate [554-13-2], Li2C02, is produced in industrial processes from the reaction of sodium carbonate and Hthium sulfate or Hthium chloride solutions. The reaction is usually performed at higher temperatures because aqueous Hthium carbonate solubiHty decreases with increasing temperatures. The solubiHty (wt %) is 1.52% at 0°C, 1.31% at 20°C, 1.16% at 40°C, 1.00% at 60°C, 0.84% at 80°C, and 0.71% at 100°C. Lithium carbonate is the starting material for reactions to produce many other Hthium salts, including the hydroxide. Decomposition of the carbonate occurs above the 726°C melting point. 

Sodium nitrate is used as a fertiliser and in a number of industrial processes. In the period from 1880—1910 it accounted for 60% of the world fertiliser nitrogen production. In the 1990s sodium nitrate accounts for 0.1% of the world fertiliser nitrogen production, and is used for some specific crops and soil conditions. This decline has resulted from an enormous growth in fertiliser manufacture and an increased use of less expensive nitrogen fertilisers (qv) produced from synthetic ammonia (qv), such as urea (qv), ammonium nitrate, ammonium phosphates, ammonium sulfate, and ammonia itself (see Ammonium compounds). The commercial production of synthetic ammonia began in 1921, soon after the end of World War I. The main industrial market for sodium nitrate was at first the manufacture of nitric acid (qv) and explosives (see Explosives and propellants). As of the mid-1990s sodium nitrate was used in the production of some explosives and in a number of industrial areas. 

Beryllium Oxide. Beryllium oxide [1304-56-9], BeO, is the most important high purity commercial beryllium chemical. In the primary industrial process, beryllium hydroxide extracted from ore is dissolved in sulfuric acid. The solution is filtered to remove insoluble oxide and sulfate impurities. The resulting clear filtrate is concentrated by evaporation and upon cooling high purity beryllium sulfate, BeSO 4H20, crystallizes. This salt is... 

There are two main processes for the synthesis of ethyl alcohol from ethylene. The eadiest to be developed (in 1930 by Union Carbide Corp.) was the indirect hydration process, variously called the strong sulfuric acid—ethylene process, the ethyl sulfate process, the esterification—hydrolysis process, or the sulfation—hydrolysis process. This process is stiU in use in Russia. The other synthesis process, designed to eliminate the use of sulfuric acid and which, since the early 1970s, has completely supplanted the old sulfuric acid process in the United States, is the direct hydration process. This process, the catalytic vapor-phase hydration of ethylene, is now practiced by only three U.S. companies Union Carbide Corp. (UCC), Quantum Chemical Corp., and Eastman Chemical Co. (a Division of Eastman Kodak Co.). UCC imports cmde industrial ethanol, CIE, from SADAF (the joint venture of SABIC and Pecten [Shell]) in Saudi Arabia, and refines it to industrial grade. 

In a widely used industrial process, the mixture of ethylene and propene that is obtained by dehydrogenation of natural gas is passed into concentrated sulfuric acid. Water is added, and the solution is heated to hydrolyze the alkyl hydrogen sulfate. The product is almost exclusively a single alcohol. Is this alcohol ethanol, 1-propanol, or 2-propanol Why is this particular one formed almost exclusively ... 

Figure 4-13 shows an example from a three-dimensional model simulation of the global atmospheric sulfur balance (Feichter et al, 1996). The model had a grid resolution of about 500 km in the horizontal and on average 1 km in the vertical. The chemical scheme of the model included emissions of dimethyl sulfide (DMS) from the oceans and SO2 from industrial processes and volcanoes. Atmospheric DMS is oxidized by the hydroxyl radical to form SO2, which, in turn, is further oxidized to sulfuric acid and sulfates by reaction with either hydroxyl radical in the gas phase or with hydrogen peroxide or ozone in cloud droplets. Both SO2 and aerosol sulfate are removed from the atmosphere by dry and wet deposition processes. The reasonable agreement between the simulated and observed wet deposition of sulfate indicates that the most important processes affecting the atmospheric sulfur balance have been adequately treated in the model. 

Therefore, polysulfide ions play a major role in the global geological and biological sulfur cycles [1, 2]. In addition, they are reagents in important industrial processes, e.g., in desulfurization and paper production plants. It should be pointed out however that only sulfide, elemental sulfur and sulfate are thermodynamically stable under ambient conditions in the presence of water, their particular stabihty region depending on the redox potential and the pH value [3] ... 

Out of the metal oxides, sulfated titania and tin oxide performed slightly better than the sulfated zirconia (SZ) catalyst and niobic acid (Nb205). However, SZ is cheaper and readily available on an industrial scale. Moreover, it is already applied in several industrial processes (7,8). Zirconia can be modified with sulfate ions to form a superacidic catalyst, depending on the treatment conditions (11-16). In our experiments, SZ showed high activity and selectivity for the esterification of fatty acids with a variety of alcohols, from 2-ethylhexanol to methanol. Increasing... 

Prominent among the heavy metals found in the wastewater generated in the copper sulfate industry are copper, arsenic, cadmium, nickel, antimony, lead, chromium, and zinc (Table 22.11). They are traced to the copper and acids sources used as raw materials. These pollutants are generally removed by precipitation, clarification, gravity separation, centrifugation, and filtration. Alkaline precipitation at pH values between 7 and 10 can eradicate copper, nickel, cadmium, and zinc in the wastewater, while the quantity of arsenic can be reduced through the same process at a higher pH value. 

Wastewater treatment in the copper sulfate industry can further be improved, particularly the removal of the toxic metals, through sulfide precipitation, ion exchange, and xanthate processes. Addition of ferric chloride alongside alkaline precipitation can improve the removal of arsenic in the wastewater. 

The two pinenes are obtained from Crude Sulfate Turpentine (CST), which is a side product of the sulfate cellulose process from pine trees. Limonene is present in orange and lemon peels [which provide different enantiomers/ )], and is a cheap by-product of the citrus industry. 

This paper has described advantages of the sinq>le DDO ciystallizer for production of calcium sulfite in a bench-scale study and calcium sulfate dihydrate (gypsum) in an industrial process. 

Calcium sulfate is formed as a byproduct in industrial processes such as flue gas desulfurization and the production of zinc, fluoride, organic acids and phosphoric acid, in amounts of many million tons per year. In this study the attention is focussed on calcium sulfate from the production of phosphoric acid for fertilizer applications. It is precipitated, from solution after digestion of phosphate ore by addition of sulfuric acid according to [1] ... 

The production of the nylon precursor e-caprolactam via the Beckmann rearrangement is one of the largest industrial processes worldwide. There are a large number of synthetic routes to e-caprolactam, most of which need to be improved because, without exception, all are multistage processes that produce large amounts of by-products, primarily ammonium sulfate. Due to its industrial application, the improvement of the Beckmann rearrangement of e-caprolactam was the aim of several smdies and a lot of scientific papers, patents and book chapters have been published on this topic during the last century. 

The rearrangement was done in similar ways by different caprolactam producers, and the differences can only be found in the purification processes. With the formation of ammonium sulfate being the most important problem for the producers of e-caprolactam, and due to the rising costs of its removal, many companies searched for new possibilities to produce caprolactam. There are some important industrial processes avoiding the cyclohexanone oxime as an intermediate product. 

In another industrial process, flue dusts from smelting lead and zinc concentrates are boiled in acidified water. Thallium dissolves and is separated from insoluble residues by filtration. Dissolved thallium in solution then is precipitated with zinc. Thallium is extracted from the precipitate by treatment with dilute sulfuric acid which dissolves the metal. The solution may also contain zinc, cadmium, lead, copper, indium, and other impurities in trace amounts. These metals are precipitated with hydrogen sulfide. The pure thallium sulfate solution then is electrolyzed to yield thallium. 

No measurement of exposure to diethyl sulfate was available for the industrial processes investigated in the epidemiological studies. It is therefore difficult to assess the contribution of diethyl sulfate to the increased cancer risks. Furthennore, exposure to mists and vapours from strong inorganic acids, primarily sulfuric acid (see lARC, 1992b), may play a role in increasing these risks.]... 

In addition to large-scale industrial applications, solid acids, such as amorphous silica-alumina, zeolites, heteropoly acids, and sulfated zirconia, are also versatile catalysts in various hydrocarbon transformations. Zeolites are useful catalysts in fine-chemical production (Friedel-Crafts reactions, heterosubstitution).165-168 Heteropoly compounds have already found industrial application in Japan, for example, in the manufacture of butanols through the hydration of butenes.169 These are water tolerant, versatile solid-phase catalysts and may be used in both acidic and oxidation processes, and operate as bifunctional catalysts in combination with noble metals.158,170-174 Sulfated zirconia and its modified versions are promising candidates for industrial processes if the problem of deactivation/reactivation is solved.175-178... 

The continually increasing demand for environmentally friendly industrial processes has also led to the development of techniques for recycling of the remaining 5-30% sulfate contained in the acidic wash water [2.55]. In modern processes, up to 99 % of sulfuric acid can be recovered and reused in production. In the chloride process, wastewater problems arise if the raw material contains < 90% Ti02. The metal chloride by products are sometimes disposed of in solution by the deep well method (e.g., at Du Pont). The metal chloride solutions are pumped via deep boreholes into porous geological strata. Special geological formations are necessary to avoid contamination of the groundwater by impurities. 

In the industrial process, a mixture of ammonium sulfate or chloride and sodium dichromate is calcined [3.50] ... 

An industrial process [5.289] operates with solutions of zinc sulfate and zinc chloride in the ratio 1 2. Basic zinc carbonate is precipitated by feeding simultaneously the zinc salt solution and a mixed solution of sodium hydroxide and sodium carbonate into a reactor charged with water. The precipitated product is intensively washed several times and then spraydried. 

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