DE1915645B - Additive to reduce or prevent caking of sodium chloride or mixtures of substances containing sodium chloride - Google Patents

Description

There are already numerous substances or mixtures of substances known that allow a reduction or prevention of the caking of sodium chloride, in particular the soluble ones mentioned in German patents 954 691 and 881 190 Ferro or ferricyanide occupy a special position, as these compounds are used in technology have proven particularly effective in preventing sodium chloride from caking. Farther a process was described in the German Auslegeschrift 1052 966 in which the sodium chloride a dissolved complex cyanide of iron. Cobalts. Nickel, ruthenium, etc. is added, wherein the Kat'on can be any which with the anion in aqueous solution an ionizing salt forms, d. h .. that these compounds must be more or less soluble in water. In the professional world was consequently so far the endeavor has been based on water-soluble use complex cyano compounds.

These additives, as well as numerous additives that prevent the sodium chloride from sticking together, are water-soluble and can be washed out by moisture or atmospheric precipitation. They are therefore not very suitable as an anti-caking additive for spreadable products when stored outdoors.

The aim and object of the present invention was therefore to find an additive that both The baking tendency of sodium chloride or salt mixtures containing sodium chloride is reduced and that cannot be washed out.

According to the invention it has been found that these requirements are met by a method for reducing or preventing the caking of sodium chloride with the use of alkali metal hexacyanoferrate as an additive! is fair, in which per kilogram of salt a solution, colloidal solution, suspension or emulsion of an additive, consisting of 0.5-10 "· * to 1.0-10" ¹ mol, preferably 0.2 × 10 " ^J to 1 , 0 · 10 " ³ mol of alkali hexacyanoferrate (II) and zinc compounds in a molar ratio of alkali hexacyanoferrate (II) to the zinc compound, such as 1: 0.8 to 1: 1.4, is added.

ίο The reaction product of soluble alkali hexacyanoferrate and a zinc salt is called zinc milk in the following. The use is advantageous here water-soluble zinc salts, preferably zinc chloride, sulfate or acetate or mixtures of water-soluble zinc salts Zinc salts. Instead of a soluble zinc. .Izes can also be used a zinc compound, those in combination with alkali metal hexacyanoferrate, optionally with the addition of a solubilizer a colloid-soluble reaction product or a reaction product in suspension or emulsion form results. Ais soluble hexacyanoferrate preferably the alkali hexacyanoferrates known per se as anti-caking agents are used. Particularly useful is the use of potassium hexacyanoferrate

(II), which also shows the best properties in terms of reducing the tendency to bake.

According to the invention, v. 'Was also found. that the specified molar ratios must be adhered to if washing out is to be avoided or a reduction in the tendency to baking in the open air is to be ensured. For example, it was found that with a molar ratio of (Fe (CN) ₆ T ¹ "to Zn above 1: 1.4, for example 1: 1.5, flocculation already occurs when the components are put together and that the anti-caking effect is significantly reduced.

In experiments carried out in the laboratory and in the open air according to the present invention, include weight ratios from 0.025 to 5 g. preferably 0.1 to 0.5 g of potassium hexacyanoferrate (II) and 0.015 to 7.5 g. preferably 0.1 to 0.7 g of zinc chloride per kilogram of sodium chloride been used. The advantages of the method of the invention are from those listed below Examples and tables clearly visible. While within one tried with several Layers when using potassium hexacyanoferrate (II) alone wash out the Additive is observed. can this washout and thus the loss of effectiveness or decrease in effectiveness of the additive in the inventive Procedures are largely avoided.

The advantage achieved by the invention is considerable in that, when stored outdoors, these water-soluble additives are caused by moisture. Rain and similar atmospheric influences such as precipitation and the like are easily washed out. This washing can be done in zones, so that, for example, the salt treated with the additive in the upper layers contains hardly any or only small amounts of these additives , so that the upper layer or layers can then easily bake together, while the layers below accumulate at this additional

can experience substances. These water-soluble cyanides on their own therefore have certain disadvantages as an anti-caking additive for stable products during storage outdoors.

Example A.
Manufacture of the additive

Zinc salt solutions were added to a four-molar aqueous potassium hexacyanoferrate (U) solution, so that the molar ratio of (Fe (CN) ₆ ) to Zn was 1: 0.8, 1: 0.85, 1: 0.9, 1: 0 , 95, 1: 1.0, 1: 1.1, 1: 1.2 and 1: 1.4. 90 ml of these solutions or suspensions were placed in seven 100 ml measuring cylinders and observed for 3 weeks. Of zinc salt. Zinc acetate, zinc chloride and zinc sulfate were preferably used. The three week test just mentioned was carried out for each zinc salt. In all three cases, a separation into a liquid and solid phase could not be determined even after 3 weeks. Investigating molar ratios of (Fe (CN) ₆ ) ⁴ " to Zn above 1.4 made little sense, since flocculation of solids occurred as soon as the components were put together.

An aqueous solution of potassium hexacyanoferrate (II) and zinc acetate in a molar ratio of i: 1 was made with 6000 revolutions per minute centrifuged. According to the analysis, the precipitate obtained has the following composition:

K ₂ Zn ₃ (Fe (CN) ₆ ), 7K ₂ O
what a molar ratio of 1: 1.5 door

(Fe (CN) ₆ ; * -

layer Addition mg / kg salt gsalt mg K ₄ (Fe (CN) _n )
3 H; O / kg salt Al
I] 100 mg
K ₄ (Fe (CNy -3H ₂ O 839
633
925 29.9
42.8
40.0

IO shift

Add salt

100 mg

K ₄ (Fe (CN) ₆ ) -3 H ₂ O as zinc milk

100 mg

K ₄ (Fe (CN) ₆ ) -3 H ₂ O as zinc milk

iOOmg zinc milk

100 mg zinc milk

gsalt

tu 7.Vl ²⁺ corresponds.

Molar ratio for 1) 1 3) 1: 1.4.

860

671

846

920 756 715 811 756 802

mgK ₄ (Fe, 'CNU 3 H, O / kf salt

77.7

83.9

70.0 85.5 92.0 86.5 67.7 81.9 87.6

1; for 2) 1: 1.1 and door

Examples Example J

To explain the addition of a zinc milk in one of the concentration ratios given in Example A. The following comparative experiment is referred to as the progress that can be achieved with sodium chloride. A dedusted rock salt was made with 100 mg of potassium lexacyanoferrate (II) and 100 mg zinc milk (the weight refers to the

K ₄ (Fc (CN) ₆ ) -3H ₂ O)

added per kilogram of salt. 2400 g each of the two mixtures were poured into a cylindrical dropping funnel given and then washed with saturated sodium chloride solution. The salt was in three Layers (Λ, B and C) removed and analyzed. |) ic results are reported in Table 1. Example! 2

The studies named below illustrate the anti-caking effect of zinc milk. Dusted Rock salt was made with different amounts of Kaliumhexacyanoferrat (II) or zinc milk and each 3% water added. Cylindrical test specimens were produced from these mixtures, which were heated at 90.degree Were dried for 48 hours. The fragmentation pressure of the served as a measure of the anti-caking effect Moldings. These are listed in Table 2.

Table 2

0 sample means salt with 3% water without the addition of an anti-caking agent.

55

Table 1

The 2400 g of the prepared mixtures were each washed with 600 ml of NaCl sol. The cyanide contents determined after washing are given as K ₄ (Fe (CN) ₆ ) -3 H ₂ O. In the table below, the last column says that the additive was still contained in the salt in the specified amount after washing. The zinc milk was used in molar ratios of 1: 1, 1: 1.1 and 1: 1.4 (potassium hexacyanoferrate (II) to zinc acetate).

Addition mg / kg salt

60

0 sample

10 mg K ₄ (Fe (CN) ₆ )

25 mg K ₄ (Fe (CN) ₆ )

50 mg K ₄ (Fe (CN) ₆ )

100 mg K ₄ (Fe (CN) ₆ )

150 mg K ₄ (Fe (CN) ₆ )

200 mg K ₄ (Fe (CN) ₆ )

3H ₂ O, 3H ₂ O, 3H ₂ O, 3H ₂ O, 3H ₂ O, 3H ₂ O.

Crushing prints

kg / cm \

27.75 3.10 2.70 0 0 0 0

1

Addition mg / kg salt

O sample

10 mg

25 mg

50 mg

100 mg

150 mg

200 mg

0 sample
50 mg
100 mg
150 mg
200 mg

50 mg
100 mg
150 mg
200 mg

calculated as

K ₄ (Fe (CN) ₆ ) 3H ₂ O, which is present in the reaction product of Zn (CH ₃ COO) ₂ with
K ₄ (Fe (CN) ₆ ) -3 H ₂ O
(Zinc milk) is included.

calculated as

K ₄ (Fe (CN) ₆₎ -3H ₂ O, in the reaction product of ZnSO ₄ K ₄ (Fe (CN) ₆₎ - 3 H ₂ O is contained.

K ₄ (Fe (CN) ₆ ) -3 H ₂ O, which is contained in the reaction product of ZnCl ₂ with K ₄ (Fe (CN) ₆ ) 3H ₂ O.

Disintegrating

dulling jerk

kg / cm ³

31.09 5.67 4.89 2.46 1.17 1.17 0.78

33.63 2.74 1.76 0 0

4.30 0 0 0

The molar ratio in all three cases of zinc milk was 1: 1.

Example 3

To show that the highest anti-caking effect is achieved with an aqueous suspension of zinc milk can be, the following comparative tests were carried out.

given. The two parts were mixed separately, then combined and remixed.

The aqueous proportions were always calculated so that the salt contained 3%. Cylindrical shaped bodies were again produced from these mixtures, which were ^{dried at 90 °} C. for 48 hours and then shattered. The results are given in the table.

Table 3

O-sample means salt with 3% water and no added anti-caking agent.

A dust-free rock salt was _{mixed dry with the K 2} Zn ₃ (Fe (CN) ₆ J ₂ · 7H ₂ O mentioned in Example 1 and then 3% water was added.

2. An aqueous solution of potassium hexacyanoferrate (II) and zinc acetate were added to the dedusted salt given and mixed so that a zinc milk could develop on the salt.

3. Sodium chloride was separated into two equal portions. One part became an aqueous one Solution of potassium hexacyanoferrate (II) and the other part a solution of zinc acetate Addition of mgAg salt

1. 0 sample

<0mg

mg

mg

mg

mg

mg

2. O sample

mg

mg

mg

mg

mg

mg

3. O sample

mg

mg

mg

mg

mg

mg

K ₂ Zn ₃ (Fe (CN) ₆ ), -7H ₂ O

mixed dry

mixed dry

mixed dry

mixed dry

mixed dry

Zinc milk by adding
aqueous potassium hexacyanoferrate (II) and zinc acetate solution are formed on the salt
leave

Zinc milk by adding
individual components
two portions of salt and then mix up
let the salt arise

Disintegrating

debris printing

kg cnr

28.59 10.55 10.56 11.73

9.38 10.16

9.35

28.15 '6.63 7.39 6.25 5.86 5.08 4.69

33.63 5.27 4.07 3.82 2.34 1.76 1.76

Claims (3)

915645 claims: 1. A method for reducing or preventing the caking of sodium chloride or mixtures of substances containing sodium chloride with the use of alkali hexacyannferrate, characterized in that a solution, colloidal solution, suspension or emulsion of an additive consisting of 0.5-10 "'to per kilogram of salt 1.0-IU " ² moles of alkali metal hexacyanoferrate (II) and zinc compounds . ■ :. a molar ratio of alkali hexacyanoferrate (II) to zinc compound, such as 1: 0.8 to 1: 1.4, is added. 2. Methods for reducing or preventing caking of sodium chloride according to claim 1, characterized in that a soluble zinc salt or a zinc compound is added in combination with alkali hexacyanoferrate with the addition of a solubilizer, that is a colloid-soluble reaction product or a reaction product in suspension or Emulsion form results. 3. Methods for reducing or preventing caking of sodium chloride according to claims 1 and 2. characterized in that potassium hexacyanoferrate (II) and water-soluble Zinc salts in a molar ratio of 1: 0.8 to 1 .1.4 are added as additives.