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Determination method of practical solubility of calcium sulfate for papermaking filler

A measurement method and technology of paper-making fillers, which are applied in the direction of weighing by removing certain components, can solve the problems that the loss of calcium sulfate fillers cannot be objectively reflected, and the actual retention rate of the fillers in the measurement results cannot be mutually verified, so as to achieve the operation steps simple effect

Inactive Publication Date: 2011-11-30
CHINA NAT PULP & PAPER RES INST CO LTD
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Problems solved by technology

Since the hydrolyzate of calcium sulfate in the form of ions, ion pairs, or semi-dissolved states is difficult to retain in the paper fibers, the molar solubility value obtained by titrating the filtrate cannot objectively reflect the sulfuric acid in the papermaking pulp making process. The actual loss of calcium fillers, so that the measurement results of paper ash and the actual retention rate of fillers cannot be mutually confirmed

Method used

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  • Determination method of practical solubility of calcium sulfate for papermaking filler
  • Determination method of practical solubility of calcium sulfate for papermaking filler

Examples

Experimental program
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Embodiment 1

[0025] Calcium sulfate test sample is natural mechanically ground hydrous gypsum. The determination steps are as follows:

[0026] (1) Pretreatment: take about 50g of calcium sulfate sample, place it in a controllable drying oven at (105±2)°C and dry it to constant weight, and set aside;

[0027] (2) Sampling: take by weighing 2.0012g of the sample gained in step (1) with an analytical balance of one ten-thousandth;

[0028] (3) Dispersion: Place the sample obtained in step 2 in a 500ml glass beaker, add 200ml of deionized water to disperse, and the resulting dispersion concentration is 0.99%;

[0029] (4) Heating and stirring: heat the dispersion obtained in step (3) in a water bath, keep the heating temperature of the dispersion at 40°C, and continue to stir gently for 60 minutes;

[0030] (5) Suction filtration: place the filter paper with constant weight (0.9312g) in the Buchner funnel, carry out suction filtration to the dispersion obtained in step (4), and use 150ml de...

Embodiment 2

[0035] In a smelter, the industrial waste slag of non-ferrous metals purified by the solvent method reacts with calcium oxide to produce fibrous synthetic calcium sulfate whiskers. The whiteness of the products is >90%; the average aspect ratio of the whiskers is 38:1; it is burned at 900°C Weight loss of 16.7%; filler for cultural printing paper.

[0036] Take 3.15 g of the pretreated dry synthetic calcium sulfate whisker sample, and disperse it for 60 min at a concentration of 0.7% and a temperature of 50°C. Adopt two kinds of solubility experimental methods to measure the solubility index of synthetic calcium sulfate whisker and list Table 1.

[0037] Calcium sulphate whiskers are used as paper fillers, and the amount added to the pulp is 25%; the concentration of the slurry is 0.5%, the ash content of the slurry is 5.58%, and the ash content of the plant fiber in the slurry is 3.37%. The filler retention experiment was carried out in the DFS-03 papermaking slurry dynamic ...

Embodiment 3

[0044] A paper mill uses the industrial waste residue produced by desulfurization in a thermal power plant to react with sulfuric acid to produce synthetic calcium sulfate, which is used as a filler for cultural printing paper.

[0045] One, adopt the inventive method to measure the practical solubility of synthetic calcium sulfate, and assay step is as follows:

[0046] (1) Pretreatment: Take 50 g of synthetic calcium sulfate whiskers and dry them to absolute dryness for later use, at a drying temperature of (105±2)°C;

[0047] (2) Sampling: take by weighing 2.0004 g of the sample gained in step (1) with an analytical balance with a sensitivity of one ten thousandth;

[0048] (3) dispersion: the sample of step (2) gained is placed in the glass beaker of 500ml, adds the deionized water dispersion of 300ml, and gained dispersion concentration is 0.66%;

[0049] (4) Heating and stirring: heat the dispersion obtained in step (3) in a water bath and continue to stir gently for 60...

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Abstract

The invention relates to a method for measuring the practical solubility of calcium sulfate for papermaking filler. It belongs to the field of papermaking. Disperse an appropriate amount of absolute-dry calcium sulfate in water at a certain concentration, heat, stir, and filter the dispersion. From the quality difference between the filter residue and the absolute-dry calcium sulfate sample, calculate the temperature and concentration of calcium sulfate through the relevant formula. Practical solubility below. This experimental method solves the problem that the traditional calcium sulfate solubility determination method cannot objectively reflect and evaluate the loss of filler in the papermaking process and the retention rate of filler in filled paper.

Description

technical field [0001] The invention relates to a method for measuring the practical solubility of calcium sulfate for papermaking filler. It belongs to the field of papermaking. Background technique [0002] Calcium sulfate is commonly known as "gypsum", including natural hydrous or anhydrous ground gypsum powder, and synthetic gypsum powder or gypsum whiskers made from natural mineral raw materials or industrial waste residues. Chemical formula: anhydrite CaSO 4 ; Hydrated gypsum CaSO 4 ·nH 2 O. [0003] The determination of the solubility of calcium sulfate usually adopts the method of dispersion of calcium sulfate in the water phase → dissolution → filtration → titration of the filtrate, and the result of this method is the molar solubility of calcium sulfate. The principle of titration is to use Ca 2+ with C 2 o 4 2- can form intolerant precipitates, making Ca 2+ Precipitates from solution as CaC 2 o 4 , washed with H 2 SO 4 Dissolve the precipitate, then ...

Claims

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Application Information

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IPC IPC(8): G01N5/04
Inventor 孙德文宋宝祥狄宏伟许泽红
Owner CHINA NAT PULP & PAPER RES INST CO LTD
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