Retention and stirring time 60 minutes. Additives used to control fouling contain magnesium, silica, manganese, and/or … concurrently with and in the same container or softener, in which water for industrial purposes is softened by means of the 40 well-known hot lime and soda ash Process, Thus, the removal of silica by magnesium oxide can proceed simultaneously with the removal of hardness from the water, as illustrated by TABLE IV A t Effect of magnesium oxide in removal of silica in conjunction with hot process lime and soda softening Conditions: 1 liter samples of water; Temperature--95 C. From this table, it will be noted that th- .n-, hardness to 32 P. P. ML, and these results remain the same, even by increasing the retention time from 15 minutes to 60 minutes. EFFICIENCY OF VARIOUS FORMS OF MAGNESIUM OXIDE By comparing magnesium oxide from various difference in the physical as well as the chemical characteristics of the magnesia and magnesite, a s shown by the accompanying Table V: TABLE V Turbidity Lbs./cu. Silica scaling is one of the main bottlenecks in the reuse of papermaking effluents by reverse osmosis. The soluble silica cannot be removed by filtration. The formed magnesium oxide on the surface was carefully dissolved in 17% aqueous hydrochloric acid. M. to 110 P. P. M. In test 2. the removal of silica was from the initial 56 p. . Magnesium oxide can make it harder for your body to absorb other medicines you take by mouth. The silica reduction is accomplished through adsorption of the silica on the magnesium hydroxide precipitate. However, previous acidification increases the conductivity of the treated waters compared to the direct use of the sparingly soluble compounds. It should be added that by increasing the sodium hydroxide to the neighbor0 hood of 40 P. P. M., and the magnesium oxide to approximately 0.3 gram, this process also serves in lieu of the lime-soda process, while simultaneously operating at high efficiency in the removal of silica. Thus, natural water and brines, such as are obtained from salt lakes and wells, are uniformly considered as cornm- 15 prising two entirely different raw materials, substances or liquids. 0 200 SCommercial magnesia (source A)-.------ 17.7 s Commercial magnesia (source B)....----- 21.2 210 24.7 100 Technical magnesium oxide-------- 247 144 2 Comme rcial magnesia (source C) ----- 2 134 U. This report focuses on the use of MgO for thermal enhanced oil recovery systems in Alberta. Approximately 40 MgO slurry systems are operating in thermal enhanced oil recovery facilities in Alberta. S3 Claims. For all of the six y 70 tests run and indicated in this table, the same ly raw natural water was used and the characterisat tics of the same are first shown as characterizing io a hardness as calcium carbonate of 74 P. P. M., of oe sulphate as 4 P. P. M. and silica as 56 P. P. M. . Magnesium oxide being prepared by the dehydration of magnesium hydroxide at 350°C showed the greatest silica removal efficiency. Magnesium is removed from an aluminum alloy containing magnesium by reacting the alloy with silica to form silicon metal which dissolves in the aluminum alloy and magnesium oxide. Threshold limit for RO recovery and required silica removal were firstly determined by a removal–saturation–recovery curve. As Is typical of adsorpion reactions, a greater Quantity of magnesium xide per unit of initial silica concentration is reuired where the initial silica concentration is w than is necessary where the initial silica conentration is relatively high. al with Initial relatively high silica concen. 6). C., and so is eminently well adapted for use concurrently with the lime-soda water Analysis of original sample: 136 softening process; that the magnesia process is Hardness as CaCO3--- - ....-'- 0 best carried out with the addition of sodium hyp alkalinity as aCOs--- -----------24 droxide or ts equivalent; .and that fairly close Salnity as CaCO3 ----------- 21 25 approximation of the results thus obtained are Silica as Si02 ----------------- ...similarly achieved by thie use of the slightly less economical magnesium corbonate. i ee th form, while this form of magnesium carbonate especially in boiler water treatment, bu the. S Test 4-Using magnesium sulfate. water. In the last two columns of Table IV 0 a 50% increase in magnesium oxide to 0.15 gram, both with 15 minutes and 60 minutes retention times, the silica removal was further increased to a net result of something less than 1.0 P. p. M. The effect of higher alkalinities could have 5 been attained by using either lime or soda ash in the tests represented by Table IV, but sodium hydroxide was employed for convenience in conducting the tests, wherefore and for such purpose the lime and/or soda ash are considered substltutes for the sodium hydroxide and vice vera. In test 1 the removal of silica was effected down to a residual amount represented by 2.5 P. P. M., while the hardness was increased to 96 P. P. M., and the total alkalinity increased from 70 P. . Results confirmed that the coagulant required for silica removal in the process water is 20-50% lower than in the effluent, especially in DAF2, where the amount of suspended solids is higher and their size is smaller. Pre-acidification of the magnesium compounds increased the dissolved magnesium content, and, thus, silica removal: a 86% silica removal was obtained with both MgO and Mg(OH) 2 and a 80% with (MgCO 3) 4 ⋅Mg(OH) 2 ⋅5H 2 O. For ex%mple, the measurement of turbidity, as indicated n Table V, enables one to determine that form of nagnesia best suited for this work from similar as well as from different means of manufacture. Conditioner samples of ater Having thus described our invention, what we 1 minutes stirring and retention time claim as new and dbslre to protect by Letters Temperatur5 C dde with me nd atent of the United States is: saneiu cashae wi m i. lime-soda water softening. rhe factor of temperature control has already een mentioned as playing an important part In he efficiency of the present process, for a high emperature of approximately 950 C. In arld,. Thus for example the quantity of magnesium that Is reqired to ac-m complish the removal of a given amount of silica is considerably above that which is stoichiometri. Lime softening is one of the most common methods for removing silica from water such as make up to cooling towers, make up to boilers or boiler blow down water. ft. for calcined magnesite froi "source C" Thus, we have practically pure ma nesium oxide of a relatively light and flufl nature at one end of the scale, while a relative, low grade of heavy weight and compactness is the other end. per cu. 35 r tures, corresponding with pressures of 200 lbs. In other words, the chemical reaction involved was unpredictable, especially as It depends upon several fairly critical factors, and does not definitely follow the line of previous experience and disclosures in the existing literature and patents on industrial watertreatient. It is generally silicilic acid (H 8. NYACOL offers magnesium oxide and magnesium hydroxide (MgOH2) in two different dispersions. oxide.) However, there is an advantage in using magnesium carbonate in" a slurry form, due to commercial magnesium carbonate frequently being relatively higher in price. Comparative tests show MgO to be superior to silica sand and garnet sand for the filtration of several different particulates. and also the fact that it may be precipitated from e. r .,,nIId the slurry softening process with that of the removal of 'silica by means of magnesium oxide, it is not necessary to employ additional lime for a maintenance of the proper balance of lime-soda. All rights reserved. Sources A, B, C and D refer to four different sampleO of commercial magnesium oxide obtained from seawatel bitterns, and produced b the use of quick-lime for th, precipitation of magnesium therefrom. The facts illustrated by Table III further indicate very definitely the need for control of the alkalinity of the treated water, as unduly high alkalinity results in retaining a certain proportion of the silica in solution. Magnesium oxide is the preferred chemical because it does not increase the dissolved solids concentration of the water. Mere softening of the water by means of the lime-soda process at 950 C. effected the usual characteristic re- 70 duction in silica to 19 P. P. M., and the hardness to 38 P. P. M. during a retention time of 15 minutes. In this case, high removal rates were obtained (80-86%) at high pH (11.5), even at ambient temperature. ---------- 2M 25 20 88 11 10 50 duce a total M alkalinity of the treated water ~o~~s-.......between 20 P. P. IM. Magnesium oxide free mesoporous silica materials have low density mesoporous silica spheres showed no XRD peaks due to complete etching of MgO core. ICH.ANISIM OF RElACTION Lons by means of magnesium oxide is not a straight stoichiometric reaction, and this Is no doubt one of the principal reasons why the present process has not been earlier discovered. The low hardness of deinking paper mill … M. to 3.0 P. P. M., while the hardness of the water dropped from its initial 74 P. P. M. to 60 P. p. M., and the total alkalinity increased only from the initial 70 p. p. M. to 78 1 P. P. M. In test 3, the removal of silica was from an initial 56 P. P. M to 2.5 . recommends using NaOH as a single agent to replace soda and lime in removing silica. In substantially the same rat as that indicated by their respective weights, tl several types of magnesium oxide are efficiel ien used in the present process, the purer and :hter weight forms producing the highest efflency, while the least pure relatively heavy rms are similarly least efficient. s TABLE I 2 Analysis of original sample: .P.M. manganese oxide, calcium mide (lime), magnesium oxide (mag­ nesia), and the alkalis decrease as the results of the cbanges tak­ ing place in the products. It can be utilized as a magnesium oxide powder or granule, or converted to a magnesium hydroxide slurry for additional uses in waste water treatment. & Terms of Use. CONTROL Control of the present process isof paramount importance as is clearly shown by an examination of the accompanying tables, for If the process is not properly controlled within fairly critical limits, a substantial addition to the solid content of the water will be effected, and this, as is well known, is undesirable, especially in the treatment of boiler feedwater and only to a slightly less degree in other types of water for industrial purposes. 5H2O) were studied in this paper at three pHs (10.5, 11.0 and 11.5) and five dosages (250-1500 mg/L) at ambient temperature (∼20 °C). As the temperature of apx1mately 950 C., is substantially the same as t which is ordinarily maintained in hot-procwater softeners, it will be apparent that a h degree of efficiency of the process can be ected, when using the same for silica removal such softeners concurrently with the so-called e-soda process. Since silica becomes part of the magnesium precipitant, some means of adding already precipitated magnesium (magnesium oxide) or of precipitating magnesium in situ is used. It is also to be noted that when using no sodium hydroxide, the hardness of the water was immediately increased from 40 P. P. M. to 76 . Hot process softening can also provide very good silica reduction. 2009). P. P. . Magnesium oxide being prepared by the dehydration of magnesium hydroxide at 350°C showed the greatest silica removal efficiency. To illustrate more specifically, with no sodium hydroxide, but 0.2 gram magnesium oxide added, the silica is reduced from 22 P. P. M. to 16 P. P. M., while upon using substantially the same proportion of magnesium oxide, i. e., 0.3 gram, but adding 20 P. P. M., sodium hydroxide, there is a sharp diminution in the silica to a mere 1.5 P. P. M., and this is only slightly further reduced to 1.0 P. P. M. by doubling the quantity of sodium hydroxide. This short movie shows a Fresnel lens being used to focus light from the sun on a mixture of magnesium powder and silicon (IV) oxide in a boiling tube. We are one of the worlds principal manufacturers and suppliers of high purity calcined magnesium oxide and magnesium hydroxide products. Whereas a ratio of PProximately 24 parts or less of magnesium ide perppart of silica will effect efficient silica mov. per sq. P. light magnesium oxide-----------.... 16. by fluxing. P. p IM., while Presence of substantial quantities of sodium hydroxide reduced the hardness below that of the P alkalinity as CaCO3 --------- _ 0 M alkalinity as CaCO3 --------------- 28 Silica as SiO2 ----------------------- 22 Conditions: 3 liter samples of raw water Temperature-95" C. 20 minutes stirring and retention time Sodium Magne- Analysis of treated water hydroxide slum added oxide Pa-sac M25 . Adsorption technology is an easy and flexible method for arsenic removal with high efficiency. ON In order to eliminate the silica from natural 60 in water, various methods have heretofore been er CI. Thus, the process represented 65 pa by test 6 could not be used on a commercial scale, to especially as one great disadvantage involved in by this process, aside from its relatively Inefficient th silica removal, Is the pronounced increase in be solids content of the water treated, due to the increase in sulphate above mentioned. The MgO–SiO 2 composite prepared by aerogel method was three times higher than the MgO. Silica removal using magnesium oxide at approximately 25 °C Depending on raw water analysis, target temperature and abatement, graphs can be used to establish the amount of reaction MgO (figure 6) and, by calculating the difference, the amount to be injected. This invention relates particularly to a Process for treating and urifying natural waters, nd relates more especially to the treatment of such waters as contain silica and/or its coof Pounds, such waters being distinguished from brines In which the silica, together with other impurities,... Click for automatic bibliography It should also be understood t, when mention is hereinafter made to 95* C., -h expression is intended to represent the ene temperature range at which the process opdtes adjacent to the boiling point and as low as proximately 75* C. Additional tests were made with temperatures 23* C., but at such low temperature, it was und impossible to obtain results in any way apoximatng those obtained with the higher temratures noted in Table II, even when increasg the magnesium oxide to 0.3 gram and the irring and retention time to as much as 180 Inutes (3 hours), as compared with the 15 mmntes retention and stirring time used in each of ie comparative tests shown in Table IL In ct, with a temperature as low as 230 C., and 15 inutes retention and stirring time, the silica ontent is reduced from 22 P. P. M only to 19 . The slurries of sparingly soluble compounds were found which reduced silica to acceptable concentration levels density... S ste form, as for instance from mgn ri the net cost of silica. With other salts surface was carefully dissolved in 17 % aqueous hydrochloric acid was carefully dissolved in 17 % hydrochloric. 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