Sulfur sand mixtures

Silica gel is prepared in two stages. Firstly, an intimate mixture of sand and sodium carbonate are heated together in iron pans forming sodium silicate with the release of carbon dioxide. The sodium silicate is leached out of the cooled mixture, unreacted sand removed by filtration, and the resulting silicate solution treated with hydrochloric or sulfuric acid. 

Gadolinium is produced from both its ores, monazite and bastnasite. After the initial steps of crushing and beneficiation, rare earths in the form of oxides are attacked by sulfuric or hydrochloric acid. Insoluble rare earth oxides are converted into soluble sulfates or chlorides. When produced from monazite sand, the mixture of sand and sulfuric acid is initially heated at 150°C in cast iron vessels. Exothermic reaction sustains the temperature at about 200 to 250°C. The reaction mixture is cooled and treated with cold water to dissolve rare earth sulfates. The solution is then treated with sodium pyrophosphate to precipitate thorium. Cerium is removed next. Treatment with caustic soda solution fohowed by air drying converts the metal to cerium(lV) hydroxide. Treatment with hydrochloric or nitric acid sol-... 

Silicon tetrafluoride has been prepared by the reaction1 of concentrated sulfuric acid with a mixture of sand and calcium fluoride, at room temperature or upon mild heating. However, the product is contaminated by hydrofluoric and fluorosilicic acids. J The thermal decomposition of barium hexafluorosilicate2 is a convenient method, requiring simple apparatus and capable of producing silicon tetrafluoride of high purity. 

Mixtures can be separated by physical means because each component retains its properties (Figures 1-6 and 1-7). For example, a mixture of salt and water can be separated by evaporating the water and leaving the solid salt behind. To separate a mixture of sand and salt, we could treat it with water to dissolve the salt, collect the sand by filtration, and then evaporate the water to reclaim the solid salt. Very fine iron powder can be mixed with powdered sulfur to give what appears to the naked eye to be a homogeneous mixture of the two. Separation of the components of this mixture is easy, however. The iron may be removed by a magnet, or the sulfur may be dissolved in carbon disulfide, which does not dissolve iron (Figure 1-6). 

Figure 6 presents a comparison of the sulfur-sand mixture tests. Sand additions increase the compressive strength of the sulfur up to approximately 50 wt %. Based on these curves it would appear that 40-50 wt % of sand would produce the highest strengths. 

Table II. Compressive Strengths of Bright Sulfur—Sand Mixtures...

Thermal Expansion. Experimental results obtained from S—A—S mixtures and a conventional asphaltic concrete are also given in Table VII. Published data on asphalt cement, asphaltic concrete sulfur, sand, and limestone are also provided. The overall thermal expansion coefficient of the composite is derived from the combined effects of the individual ingredients in the mixture and the air voids present in the final material. Any combination which tends to decrease the air voids content... 

Industrial chemical processes manufacture products that differ in chemical content from process feeds, which are naturally occurring raw materials, plant or animal matter, intermediates, chemicals of commerce, or wastes. Great Canadian Oil Sands, Ltd. (GCOS), in a process shown in Fig. 1.1, produces naphtha, kerosene, gas oil, fuel gas, plant fuel, oil, coke, and sulfur from Canadian Athabasca tar sands, a naturally occurring mixture of sand grains, fine clay, water, and a crude hydrocarbon called bitumen. This is one of a growing number of processes designed to produce oil products from feedstocks other than petroleum. 

The oil sands are a geological formation of a mixture of sand, water, clay and bitumen, which is a tar-like, thick heavy oil, with an average sulfur content of... 

The CuS is then smelted, a process in which metal ions are reduced by heating the ore with a reducing agent such as carbon (in the form of coke). At the same time, the sulfur is oxidized to S02 by blowing compressed air through the mixture of ore, limestone, and sand ... 

In order to explore composition modulation of the final stage of a converter further, Briggs et al. (1978) added a second integral reactor, also holding about 30 g of the vanadia catalyst. With the preconverter in place, this system was operated on a typical feed from sulfur burning, with a S02 02 N2 composition in vol% of 10.8 15.2 74, and from a smelter effluent with a composition of 8.0 6.2 85.8. The cycled beds of vanadia catalyst were held in a fluidized sand bath at 401°C for the former feed and at 405°C for the latter one. The space velocity for both the air and the S03/S02 mixture was about 24 min 1 (STP). Table II summarizes the experimental results for the cycle periods tested. 

SAPIC A process used in metal foundries for curing resin/sand mixtures used in making molds. The resin is usually an unsaturated polyester resin. In the SAPIC process the resin is hardened by means of an organic peroxide, or hydrogen peroxide, which is activated by sulfur dioxide gas when required. 

Although neodymium is the 28th most abundant element on Earth, it is third in abundance of all the rare-earths. It is found in monazite, bastnasite, and allanite ores, where it is removed by heating with sulfuric acid (H SO ). Its main ore is monazite sand, which is a mixture of Ce, La, Th, Nd, Y, and small amounts of other rare-earths. Some monazite sands are composed of over 50% rare-earths by weight. Like most rare-earths, neodymium can be separated from other rare-earths by the ion-exchange process. 

Place a mixture of 4 parts concentrated sulfuric acid and one part denatured ethanol in a flask containing enough clean, dry sand to form a thin paste. 

The control solution is prepared as follows Evaporate a mixture of 2 mL of nitric acid, 5 drops of sulfuric acid, and 2 mL of hydrochloric acid on a water bath, further evaporate to dryness on a sand bath, and moisten the residue with 3 drops of hydrochloric acid. Proceed as directed in the test solution, then add the volume of standard lead solution directed in the monograph and water to make 50 mL. 

SAS mixes with S A ratios of 1.0 to 2.5 1.0 are recommended for use in flexible pavement mixture designs, while S A ratios greater than 5 1 can be used in situations requiring rigid pavement designs. A typical SAS formulation is 82 parts sand, 6 parts asphalt and 12 parts sulfur by weight. 

The effect of sulfur and asphalt contents in SAS mixtures on Marshall Stability is shown in Figure 3 [15]. The stability values tend to increase with sulfur content but decrease with asphalt addition. It is interesting to note that without the sulfur and asphalt, sand mixes would have little or no stability. The data also indicate a wide variety of mix designs are possible whose stabilities are consistant with Asphalt Institute suggested values for conventional asphaltic mixes. 

A characteristic of single sized sands is their comparatively high air void contents which usually exceed 30 percent. Since sulfur s role in SAS mixtures is to fill these air voids without the aid of mechanical densification, both economic and performance considerations would require analysis of the maximum permissible air void content the mixture may possess and still be relatively impermeable to water without sacrificing structural integrity. Figure 4 [15] shows the relationship between air voids content and permeability for both SAS and asphaltic concretes as determined... 

Figure 6. Heated dump body truck developed by Shell Canada, Ltd. used for hauling sand-asphalt-sulfur paving mixtures. [Photographed at the Kenedy County Texas field trials in 1977 (28)].

Mix 100 g. of granulated aluminum with 90 g. of clean line sand and 90 g. of sulfur. Place the mixture in a fire-clay crucible embedded in sand in a safe place and ignite with fuse powder and a magnesium ribbon, as described in Exercise 85. After the reaction is completed, allow the crucible to cool. Break the crucible, put the contents in an evaporating dish, and treat with water to decompose the aluminum sulfide. This should be done under the hood so that the copious fumes of poisonous H2S will be carried off. Wash away the slimy lumps of melted aluminum from such foreign matter as pieces of crucible. Place these pieces of metal in a beaker, gradually treat with commercial hydrochloric acid until the action has quieted down, then cover with the acid and let stand on the hot plate for several days,... 

Fourteen grams of finely granulated tin (20-30 mesh) are warmed gently with 6.5g of mercury in a porcelain basin under the hood. The mass is stirred with a glass rod until it is homogeneous and quickly poured into a mortar where it is ground to a fine powder as it cools. The cold pulverized amalgam is then intimately mixed with 8g of flowers of sulfur and 6.8g of ammonium chloride. The entire mixture is transferred to a loosely covered crucible which is embedded in a sand bath up to the level of the reaction mixture. The crucible is heated at 400°C in the... 

Another mixt which contained neither Zn nor CClfl was also called Berger Mixture. Its compn was pitch 29.2, saltpeter 47.4, borax 10.6, Ca carbonate 4.9, sand 4.0 sulfur 3.9%. It was cheaper but less effective than the above American Mixture... 

Greek fire is made as follows take sulfur, tartar, sarco-colla, pitch, melted saltpeter, petroleum oil, and oil of gum, boil all these together, impregnate tow with the mixture, and the material is ready to be set on fire. This fire cannot be extinguished by urine, or by vinegar, or by sand.. . . ... 

You are given 2 tablespoons of sulfur powder, some iron filings, 2 tablespoons of sugar and 2 tablespoons of sand. First, make a mixture of these substances. 

---