SU690088A1 - Method of producing sulphide-containing cellulose fibre - Google Patents

Description

(54) METHOD FOR OBTAINING SULPHID-CONTAINING PULP FIBER

I

The invention relates to methods for producing sulphide-containing fiber, it can be applied in non-ferrous metallurgy to extract non-ferrous and rare metal ions from dilute solutions.

A known method for producing sulphide-containing fiber is by molding viscose with the addition of Asj-Oj. As a result of interaction with viscose sulfides, arsenic sulfide is formed, which is soluble in alkali but is stable in acid. The disadvantage of this method is the increased harmfulness of production 1.

There is also known a method for producing sulphide-containing fiber by molding viscose into a precipitating bath containing zinc sulphate, followed by fixing the released sulfur compounds on the fiber by heat treatment in a neutral medium 2. This method does not allow to obtain fibers with high sorption capacity and, moreover, leads to the need to capture released carbon disulfide.

In order to obtain fibers with high sorption capacity and reduce production hazards, it was proposed to fix the sulfur compounds released during viscose formation by treating the fiber with an aqueous solution of sodium zincate with a concentration of 4-18 g / l at 20-90 ° C followed by washing and drying.

This method of obtaining sulphide-containing cellulose fiber is based on the ability of sodium zincate to bind sulfur xanthate, tritiocarbrnate and sulphide to form poorly soluble zinc sulphide.

To obtain sulphide-containing cellulosic fiber, waste of viscose cord production is used - spunbond, which is an undrawn, underdeveloped sodium xanthogenate fiber with a degree of substitution of xanthate V-25. The fiber also contains some carbon disulfide and by-products of viscose.

The fiber is taken from the lower cane of the PN-300-I spinning machine after forming the viscose in the precipitation bath of the composition, g / l: NgZO 100.97; ZnSO4 96.5; NaiSq 174.32. In order to prevent further saponification of xanthate and to obtain

a more stable cellulose-oxtogenic acid salt and by-products of viscose fiber are taken into a 50 g / l zinc sulphate solution in which it can be stored for 24 hours at a temperature of 18-20 ° C. The reactions occurring at the same time proceed according to the scheme

2 SbNv04OS | mv „+ ZnSO4 - (CoH, + NatSO

NajS + ZnSO + Py8O4

NaaCSj + ZnSO4, + Al5O4 Then the fiber is squeezed out of excess solution and processed with sodium zincate

CeH9O4OCt | 2Zn + SNatZnOt + -j- -2СвН, оО5 + 4ZnS + 2NaOH -f + NaiCOj

After treatment with sodium zincate, the fiber is washed to neutral with water. Drying is carried out at 40-60 ° C for 12-18 hours. - -

Example 1. The fiber is treated with a solution of zinc sulphate with a concentration of 50 g / l, then sodium zincate (module 1: lOO) with a concentration of 8 g / l for 2 hours at 80-90 ° C.

Concentration of NanZnOj,, g / l 4 Capacity, mEq / g Processing time, sodium zincate with a concentration of South / l 0.5 1.0 at-eo s, h

Static exchangeable em1, 1 1.6 1.8 fiber bone, mEq / g

From tab. 2 that the optimum processing time of the fiber in sodium zincate is 2.0 ± ± 0.5 h. With an increase in the concentration of sodium zincate, the exchange capacity of the fiber increases in solution, but at a concentration above 12 g / l the fiber dissolves due to a higher content in free alkali solution. Therefore, the fiber is treated with a solution of sodium zincate with a concentration of 10 ± 2 g / l.

: .tdgg: 1 - y; - x: ....-.

Next, the fiber is washed with water and dried at 40 ° C.

Example 2. A block was treated with a solution of zinc sulphate with a concentration of 50 g / l, 4% sodium zincate (module 1: 100) with a concentration of 12 g / l for 72 hours at 20 ° C. Next, the fiber is washed with water, dried at 40 ° C. The resulting fiber contains zinc sulfide in the amount of 14-15 ° / o of the weight of the fiber.

The sorption properties of the obtained fiber were investigated. 0.009 n. Taken to determine the static exchange capacity. Ag solution, 0.011 n. Hg solution and 0.025 n. solution (nitrate salts of silver, mercury, copper):

Static exchange capacity, mgeq / g2.1 2.0 2.3 Metal content

 on fiber, mg / g22,4 63,4 234

The dependence of the static exchange capacity of the fiber for silver on the processing time and the concentration of zinc sodium is given in Table. 1 and 2.

Table 1

table 2

2.22.2

2.0

The processing temperature of the fiber with sodium zincate does not have a noticeable effect on the capacity of the fiber; however, an increase in the temperature of the fiber drastically reduces the process. In addition, treating the fiber with sodium zincate for a long time at temperatures below 80-90 ° C is impractical because the alkali makes cellulose swell and dissolve at low temperatures (see Table 3). 1,52,02,53,0

Time h

Capacity, mEq / g 1.27 1.85

"

Claims (2)

The fiber swells rapidly, followed by dissolution. The proposed method allows to obtain a fiber having ion exchange properties with respect to ions of non-ferrous and noble metals, as well as the use of waste of viscose cord production. The method is simple to implement, makes it possible to obtain cheap ion-exchange fiber; the estimated cost is 36 kopecks. for 1 kg. In addition, the method reduces the harmfulness of production, since carbon disulfide and hydrogen sulfide released during the saponification of cellulose xanthate are converted by treatment with sodium zincate into poorly soluble zinc sulfide. Claim method for producing sulphide cellulose fiber by visco molding. Table 3 72 120 48 24 1.18 2.14 2.05 into a precipitation bath containing zinc sulphate, followed by fixing sulfur compounds released during molding, which, in order to obtain fibers with high sorption capacity and reduce the harmfulness of production, the sulfur compounds are fixed by treating the fibers with water. sodium zincate solution with a concentration of 4-18 g / l at 20-90 ° C. Sources of information taken into account in the examination 1.Chemiker Zeitung, Chemische Apparatus, 88, No. 3, 1964, 75-83. 2. USSR author's certificate for application number 2131126/05, cl. D 01 F 2/06, 1975 prototype).