Magnesium Bisulfite

It is claimed that magnesium bisulfite pulping would provide more efficient operation with the possibility of higher yields. 

Magnetite sulfurous acidc,d Magnesium bisulfite None 45-55... 

Fig. 5.2.9. Absorption spectra of spent liquors of a magnesium bisulfite pulping sequence for spruce. The spectra are measured against water (resolution 4cm 1, 64 scans). 1331, 1150 free S02 1200, 1064, 1022 HSO, 1037 lignosulfonates 1512 aromatic skeletal vibrations of lignin other identified bands indicate increases in the concentrations of organic constituents in the liquor...

Magnesium bisulfite neutralization is represented by the following reaction ... 

The Magnetite pulping process utilizes acid magnesium bisulfite solution at a pH of about 4.5 as the pulping liquor. The process produces pulp that is used to make reinforcing pulps for newsprint see Figure 15.1, which displays a schematic of the Magnetite process. The recovery of MgO is necessary for... 

Sulfur dioxide is prepared by the burning of sulfur to form sulfur dioxide, which is dissolved in water to form sulfurous acid (H2SO3) see reactions (15.1) and (15.2). The sulfurous acid is then reacted with slaked MgO to form magnesium bisulfite, reaction (15.3). Further reaction of magnesium bisulfite with excess magnesium hydroxide produces magnesium sulfite,... 

The pH of the pulping liquor has to be maintained at a pH below 5.0 due to the limited solubility of magnesium sulfite, which is about 5.5 g/L at 18°C, while that of magnesium bisulfite is 43 g per 100 g of solution at 25 °C and 1 atm sulfur dioxide (The Institute of Paper Chemistry, 1960). Figure 15.2 displays the molar fractions of sulfur dioxide, bisulfite, and sulfite present in solution as a function of pH. 

Use A soln o[ magnesium sulfite in sulfurous acid (magnesium bisulfite) is used in the manuf of paper pulp. 

The acid pulping process uses sodium bisulfite or magnesium bisulfite in a pulp digester at a pH of 3. Type 316 stainless steel is normally used as a minimum alloy because the sulfur dioxide can be converted into sulfuric acid. Sulfuric acid can corrode the stainless steel depending on the pH, temperatiire, and pressure of the system. SCC has been observed in the HAZ of weldments in the pulp digesters in the presence of sodium hydroxide. Because of SCC susceptibility of the austenitic stainless steels, duplex stainless steel 2205 is often used in pressure vessels and tanks. 

Gold Plating Solution (63% Potassium Ferrocyanide. 2% Potassium Gold Cyanide. 8% Sodium Cyanide) NR NR R R Magnesium Bisulfite Magnesium Carbonate Magnesium Chloride R R R NR NR R R R R R R R... 

For the synthesis of magnesium bisulfite complex, an aqueous solution of MgCl2 is mixed with aqueous (N2H5)2S03-H20 or (N2H4)2-H2S03-H20 stoichiometrically in a Mg SO3 ratio of 1 2. The compound is precipitated out by addition of alcohol. It is further washed with alcohol, then diethyl ether and dried in vacuum desiccator [22] ... 

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