SU833500A1 - Method of producing filler - Google Patents

Description

(54) METHOD FOR PREPARING THE FILLER

I

This invention relates to the production of finely dispersed aluminosilicate used as a filler in the manufacture of paper and rubber, as well as a pigment in the dye industry.

A method of obtaining a filler is known by treating silica-alkaline solutions with lime or lime milk 1.

However, the filler of this method is stiff and plucked when the paper is calendered.

There is also known a method for producing a filler by reacting the caustification product of silica alkaline solutions with calcium hydroxide with aluminum sulphate 2 solution.

The technology of preparation of this filler is multistage and the hardware design is rather cumbersome.

Closest to the present invention is a method for preparing a filler, comprising reacting the silica-alkaline solution with sodium aluminate in the presence of an excess of ammonium chloride when heated. The resulting precipitate is filtered, dried and ground. Get white fine powder with a grain size less than

0.05 microns and containing,%: SiOa 65-80; 2-30; 1.0-1.5 and 10-15 3.

However, obtained in a known manner, the filler has a low refractive index (N 1.46-1.48) and high dispersion, which does not provide high values of strength and opacity of paper.

The purpose of the invention is to increase the strength and opacity of the paper.

This goal is achieved in that sodium aluminate is used in an amount of PO-150% of the stoichiometry with respect to silicon dioxide contained in a silica base solution, followed by binding an excess of sodium aluminate to tricalcium hydroaluminate to absorb calcium chloride solution.

In addition, the calcium chloride solution is used with a temperature of 70-80 ° C.

The technology of the method is as follows

To a silica-alkaline solution containing 50-100 g / l of SiOj and a molar ratio of SiCferNajO (2: 1) - (3: 1) heated to 90-98 ° C, a hot (60-70 ° C) solution is added with stirring Sodium aluminate, containing 200-280 g / l AlgOj. and

300-310 g / l. The amount of sodium aluminate added to decompose the silica alkaline solution is PO-150% stoichiometry to SiOz. by reaction

.J -JuBiO -H 0 2Mi (()., - (- / VaeO DeGOSA H, Oi-3f oOH

where "is the molar ratio. The reaction time of the reactants is 30-60 minutes, then a hot (70-80 ° C) solution of calcium chloride in an amount sufficient to bind the excess alumina to the insoluble tricalcium hydroaluminate is introduced into the pulp.

2MASCHON) № OI ZSaO-A1gOz-vN20-bNyS .S

The reaction mass is stirred for more than 30 minutes at 95-98 ° C. Then the pulp is filtered, the precipitate is rinsed with water and dried. The resulting product contains,%: SiOg 33-46; AlgOj. 20-28; 10-13; CaO 5-15; Cl 1-4 and ppt 16-24, with a dispersion of 0.3-0.5 microns ,. which is used as a filler for thin printing paper.

Example .1. 386 ml of a silicon cell solution containing 207 g / l of SiOj 2.38 is diluted with 102 ml of water, heated to 95 ° C and with constant stirring, 312 ml of aluminate solution containing 200 g / l and ,four. The reaction mass is kept for 1 h at 95 ° C and under constant stirring, and then 19.7 g of CaCl2 dissolved in 50 ml of water are added and the reaction is continued for another 30 min under the same conditions. The dry precipitate is filtered off, washed with water and dried. The dry residue contains,% SiOa 39,7; AbOj 26.5; CaO 5,1; NaaO 11.0; Cl 2.0 and p.n. 15.6 ,.

Example 2. To a 25.0 ml cream non-alkaline solution containing 104 g / l of 44.8 g / l and 26.4 ml of water heated to 92 ° C, 22.0 ml of the aluminate solution containing 103.2 g / l AUO and 145 g / l NajtO. After 40 minutes of reacting the components, 1.5 g of CaCl dissolved in 10 ml of water are added at a given temperature and stirring is continued for another 30 minutes under the same conditions. The filter cake is washed and dried. The finished product contains / a: 5 South 42.6; AlaO, 2G, 2; MagO 13.0; CaO 4.8; S1L, 0 and ppp 16.8.

Prima rz. To 24.2 ml of silica solution containing 207 g / l of SiOg and 2.38 heated to 98 ° C with stirring add 35.6 ml of aluminate solution containing 150 g / l of AljOj and L.ku 2.4. After 60 minutes of reacting the components, 6.05 g of CaClg dissolved in 10 ml of water are added and the transfer is continued.

the reaction mass for another 30 min at a given temperature. The precipitate is filtered off, washed and solid. The dry product contains,% South 35.5; AlgOg 27.3; CaO 10.3; C1 3.0; NagO 13.5 and ce.p. 11.4.

Characteristics of paper samples obtained using fillers with different dosages of aluminate are given in table. one.

With a dosage of more than 150% sodium aluminate, the resulting amount of tricalcium hydroaluminate is already significant; in this case, the new phase crystallizes in the form of large rounded grains (7-13 µm), which are poorly retained in paper (easily washed out of cellulose fibers), therefore the effectiveness of this compound as filler.

At a dosage of less than 110% aluminate, the amount of tricalcium hydroaluminate formed is very small and, therefore, the filler is similar in properties to that obtained by a known method.

Data on the quality of paper obtained using known and proposed fillers are given in Table. 2

As follows from the table. 2, the proposed filler increases the opacity

papers of 3.6-4.37 j. This is explained by the fact that the filler is a sodalite-type aluminosilicate modified with tricalcium hydroaluminate. Since the coefficients of light refraction in these compounds differ significantly (1.483 and 1.603, respectively), the total coefficient increases and increases the opacity of the paper.

Paper with the proposed filler has high rates of mechanical strength, its discontinuous length is three times longer (6000–6300 m and 1900–1920 m, respectively). This is due to the different nature of the fillers: the known filler is aluminosilicate and the proposed aluminosilicate coated with tricalcium hydroaluminate has a different hardness and therefore has a different abrasive effect on cellulose fibers.

Increasing the opacity and mechanical strength of the paper makes it possible to reduce the thickness of the paper and, therefore, with the same book volume, it can hold much more printed information. In addition, the filler has a higher retention rate than the known one (55.9-60.0 and 39.0-43.0, respectively), and this contributes to its more economical consumption and reduces the pollution of industrial effluent.

95.2

1920 1900 95.3 96.0490078.29 O, 618.4 95.25200 77.991.016.5

96,26300 79.0

130

95,861OO 79.4

95.2

Famous

95.3

Offer 96.2 per cent

96.0

Table 1

14.9

90.4

39.0 16.8 43.0 90.2

94,719,260,6

94,719,660,5

Table 2 49.7 54.0

Claims (3)

1. A method of producing a filler used in papermaking, including the interaction of a silica alkaline solution and sodium aluminate solution upon heating followed by filtration of the resulting precipitate, its wash and substance, characterized in that, in order to increase the strength and opacity of the paper, sodium aluminate is used in the amount of 110-150% of stoichiometry with respect to silicon dioxide contained in the silica base solution, followed by binding an excess of sodium aluminate in tricalcium hydroaluminate by the introduction of calcium chloride solution. 2. Saoos according to claim 1, characterized in that the calcium chloride solution is used with a temperature of 70-80 ° C. Sources of information taken into account in the examination 1. USSR author's certificate No. 281438, cl. From 01 to 33/24, 1968. 2. USSR author's certificate number 136541, cl. From 01 to 33/26, .1960. 3. The patent of Great Britain No. 841831, cl. 1 (3), A, 1968 (prototype).