DD292146A5 - Non-oxidative agent for gravitational dusts - Google Patents

Abstract

A non-ionic wetting agent for heavy-wettable dust, such as coal dust, consists of an alkylpolyalkylene glycol ether of the type {wetting agent; Coal dust; schwernetzbare dusts; non-ionic wetting agent; Salt solution; Foam behavior; alkylpolyalkylene; Network time}

Description

DISCLOSURE OF THE INVENTION The invention has for its object to provide a nonionic aqueous wetting agent for sc'iwernetetzer dusts such. B.

To develop carbon dust that is also effective in the presence of salt solutions, little foams and about 40 times faster

as conventional wetting agents. '.

According to the invention the object is achieved in that as Alkylpulyalkylenglycolether 88% to 99.5%, based on the weight of the non-ionic wetting agent, compounds of the type I.

RO- (C ₃ H ₆ O) _x - (C ₂ H ₄ O) H

R is an alkyl radical of C chain length 7.8 or 9

and as cosurfactant 0.5% to 12%, based on the weight of the nonionic wetting agent, alcohols of C chain length 2 to 10 are included.

Aqueous wetting agents of this composition have an excellent wetting ability compared to difficultly wettable dusts, such. As coal dust. Nonylphenol polyglycol ethers with 8-10 moles of ethylene oxide and dioctylsulfosuccinate, which are known to be good wetting agents, have a dipping power of TNV ₍ oo = 0.75 g / l or 0.2 g / l, but do not sufficiently wet coal dust.) The new wetting agents have a TNVioo> 0.8g / l, but wet coal dust in a very short time.

Compared with Alkylphenolpolyglycclethern with 8-10 moles of ethylene oxide wetting the wetting agents of the invention coal dust about 40 times faster.

It is essential that R in I chain length is uniform. If R is subject to a chain length distribution typical of native and synthetic surfactant alcohols, the wetting power of the wovens that are difficult to wet substantially deteriorates. The use of the wetting agent is facilitated by the fact that they are prone to foam, or their foam is very unstable.

The wetting of pulverized coal reaches an optimum when R in I stands for the 2-ethylhexyl radical, χ the value of 2.5-3.5 and y the value of 2-3. The content of cosurfactants improves carbon decoating ability, especially when the C chain length of the alcohols is 6.7 or 8. It is advantageous if the ratio χ to y was chosen so that the compounds of type I are soluble or emulsoiü soluble in water.

The non-ionic wetting agent also wets coal dust in salt solutions with a high content of catcium chloride.

embodiments

The wetting rate of pulverized coal of <0.070 mm grain size was determined so that 0.5 g of pulverized coal was thrown onto the wetting agent solution and the time until the pulverized coal completely submerged was stopped. The ratio of pulverized coal to net solution was 1:33.

Composition of the network solution

Solution 1: 22.7 g CaCl ₂ ; 0.15g wetting agent, water ad 100

Solution 2: 36.4 g CaCl ₂ ; 0.225g wetting agent, water ad 100

Examples according to the present invention

In the compounds of type I, R is the 2-ethylhexyl radical, C is carbon chain length.

composition solution Sinking time in s wetting agent (Wt .-%) No. 1) Typl: χ = 2,8 98% 43 y = 2.2 1 octanol 2% 2) Typl: χ = 1.5 99% 95 y = 3 1 octanol 1% 3) Typl: X = 1.5 94% 70 y = 3 1 octanol 6% 4) Typl: χ = 3,4 91% 435 y = 3.9 2 octanol 9% 5) Typl: χ = 3,4 91% 390 y = 3.9 2 hexanol 9%

Examples according to the prior art

composition solution Sinking time in s Wetting agent (% by mass) No. > 1800 6) nonylphenol with 9 mol 1 Oxyethylan > 1800 7) dioctylsulfosuccinate, sodium salt 1 910 8) Typl, R = 2-ethylhexyl 1 χ = 6.2 y = 7.5 > 1800 9) like 8) 2 > 1800 10) Type I, R = C ₆ to C ₁₀ 2 x = 2.5

Claims (3)

1. Non-ionic wetting agent for schwernetzbare dusts, such. As coal dust, from Alkylpolyalkylenglycolether and cosurfactant, characterized in that as Alkylpolyalkylenglycolether 88% to 99.5%, based on the weight of the nonionic wetting agent, compounds of the type RO- (C ₃ H ₆ O) _x - (C ₂ H ₄ O) ₇ -H R is an alkyl radical of C chain length 7.8 or 9
X = 1 to 4 γ = 1.5 to 5 and as cosurfactant 0.5% to 12%, based on the weight of the nonionic wetting agent, C-chain aliphatic alcohols 2 to 10 are included. 2. Nonionic wetting agent according to claim 1, characterized in that R in Alkylpolyalkylenglycolether the 2-ethylhexyl and χ = 2.5 to 3.5 and y = 2 to 3. 3. Non-ionic wetting agent according to claim 1, characterized in that alcohols of C chain length of 6.7 or 8 can be used. Field of application of the invention The invention relates to a nonionic wetting agent for schwerverbetzbare dusts, such as. As coal dust. Characteristic of the known state of the art Addition products of oxyethylene and oxypropylene to compounds having at least one reactive hydrogen atom are known as wetting agents (Schick, "Nonionic Surfactants", Marcel Decker Inc., New York, 1967). DE-PS 2448388 describes microorganism-degradable surfactants of the formula RO- (CH ₂ -CH-O) _x - (CHrO) _y -H
R ' R is a straight-chain alkyl radical having an average carbon atom number of about 6 to about 10, R 'is a straight-chain alkyl radical having 1 to 6 carbon atoms, χ is an integer from about 1 to about 6, and γ is a number from about 4 to about 15. In DE-PS 3431156 biodegradable detergent and detergent compositions of the formula RO- (C ₃ H ₆ OL- (C ₂ H ₄ OIb-H wherein R is a linear or substantially linear alkyl group of 6-10 carbon atoms, a has a mean of 4.5-9, and b has an average of 2 to 9. Nonionic surfactants with this chemical structure are good wetting agents for detergent formulations, but have the disadvantage that they completely noxious coal dust (network times greater than 30min). DD-PS 250541 describes a little Staubbildenrta particular composition, are stabilized by the dyes with ethoxylated oxethylated alkylphenols of the degree of ethoxylation 3-20 against dust formation. Aikylphenoloxethylate this Oxethylierungsbereiches are hardly effective for the wetting of coal dust (network times greater than 30min). Processes for the preparation of dust-binding agents and pastes or dust-binding agents and pastes particularly adapted for binding coal dust are given in DE-PS 1492297, 1492458, 2414927, 3300848 and US-PS 3928222, 3954662, 4067818. These patents describe more or less alkaline earth alkali hydroxide / Erdalkalichloridmischungen with partial additions to a variety of wetting agents such. Example, ethoxylated alkylphenols, ethoxylated alcohols of the C chain length of 6 to 30 and dialkylsulfosuccinates. The carbon dust-binding capacity of these agents and pastes is emphasized; nothing is known about their wetting action in relation to difficultly wettable dusts. An improvement in the network effect is achieved according to DE-PS 2702186 by combining ethoxylated nitrogen bases with hydrotropes such as alkyl-o-xylenesulfonsäure. The disadvantage is that this combination works only at very low salt contents of 500-5OOOppm. US Pat. No. 4,425,252 describes a wetting agent based on alkylphenol with 10 mol of oxyethylene, the sodium salt of dodecylbenzenesulfonic acid, isopropanol, diethylene glycol monobutyl ether and water. The net wetting times achieved for 50 mg of pulverized coal were given for an optimized formulation of 3.9 min, with the wetting agent being distilled in dist. Water with only 440ppm calcium ion additive was dissolved. For this small amount of coal dust, the net time is too long. The hardness compatibility with 440ppm is also not satisfactory. Object of the invention The aim of the invention is to reduce the cost of materials for the binding of crosslinkable dusts in water and salt solutions.