Search

EP-3727663-B1 - USE OF AQUEOUS SOLUTION OF ORGANIC AMMONIUM CARBOXYLATE IN PREVENTING DUSTING OF FINE MATERIAL AND COMBINATION OF AN AQUEOUS SOLUTION OF ORGANIC AMMONIUM CARBOXYLATE AND FINE MATERIAL

EP3727663B1EP 3727663 B1EP3727663 B1EP 3727663B1EP-3727663-B1

Inventors

  • Ahlnäs, Thomas

Dates

Publication Date
20260506
Application Date
20181221

Claims (20)

  1. The method for spraying an aqueous solution of organic ammonium carboxylate of formula (I): [NR 1 R 2 R 3 R 4 ] + [R 5 (COO)] - , (I), in which R 1 , R 2 , and R 3 are selected from the group composing of hydrogen and methyl, R 4 is a C 1 -C 4 -alkyl substituted with a hydroxyl group, R 5 is hydrogen or methyl; as a mist or drops onto fine material to prevent dusting of fine and to lower the freezing point of said aqueous solution of organic ammonium carboxylate of formula (I): after said solution of aqueous organic ammonium carboxylate of formula (I):has been sprayed on the surface of said fine material; wherein said fine material is selected from the group composing of sand, crushed stone, crushed expanded clay, or crushed expanded clay aggregate, crushed cement or concrete and chopped organic material, in which method the concentration of ammonium carboxylate, in the aqueous solution of organic ammonium carboxylate of formula (I), which will be sprayed onto fine material is- in the range of 1 -50 %wt, wherein either a) said aqueous ammonium carboxylate solution of formula (I) is applied as a mist onto the surface of fine material in a case the average particle size of said fine material is 0,125 -0,025 mm (125 -25 um) wherein said mist have average particle size under 1.5 times of average particle size of said fine material or b) said aqueous ammonium carboxylate solution of formula (I) is applied as drops onto the surface of said fine material in a case the average particle size of fine material is over 0,4 mm (400 um).
  2. The method defined in claim 1, which additionally comprises controlling the hydrophobicity and the hydrophilicity of the fine material which control is based on the concentration of ammonium carboxylate in aqueous solution of formula (I).
  3. The method defined in claim 1, wherein the concentration of organic ammonium carboxylate in the aqueous solution of formula I is in the range of 1-10 % wt-%, preferably in the range of 2-5 wt-%.
  4. The method defined in any of the previous claims, in which the freezing point of the aqueous solution of organic ammonium carboxylate of formula (I) is in the range of -5 to -50°C.
  5. The method defined in any of the previous claims, wherein the surface of the fine material which have been treated with aqueous solution of organic ammonium carboxylate of formula (I) is hydrophilic.
  6. The method defined in any of the previous claims, wherein said fine material is crushed expanded clay, crushed expanded clay aggregate, crushed peat, peat powder or chopped wood,.
  7. The method defined in claim 1 , wherein preventing of dusting of fine material and in lowering the freezing point of said aqueous solution present on the surface of said fine material, by spraying said mist or drops onto fine ,additionally comprises controlling the hydrophobicity and the hydrophilicity of the fine material which control is based on the concentration of ammonium carboxylate in aqueous solution of formula (I).
  8. The method defined in any of the previous claims 1 - 7 , wherein R 1 , R 2 and R 3 are all hydrogen and R 4 is an ethyl substituted with a hydroxyl group, preferably 2-hydroxy ethyl.
  9. The method defined in any of the previous claims 1-8 , wherein R 1 , R 2 and R 3 are all methyl and R 4 is an ethyl substituted with a hydroxyl group, preferably 2-hydroxy ethyl.
  10. The method defined in any of the previous claims 1-9 , wherein the organic ammonium carboxylate of formula (I) is a salt of formic acid and monoethanolamine or a salt of acetic acid and monoethanolamine.
  11. The method defined in any of the previous claims 1-10 , wherein the aqueous solution of organic ammonium carboxylate of formula (I) contains organic ammonium carboxylate of formula (1) and water in a weight ratio in the range of 1:50-1: 15, preferably in the range of 1:33-1:20.
  12. The method defined in any of the previous claims 1-11 , wherein the aqueous solution of organic ammonium carboxylate of formula (I) contains distilled water only.
  13. The method defined in claim any of the previous claims 1-12 , wherein the concentration of sodium, potassium, calcium and magnesium is 0 M in the aqueous solution of organic ammonium carboxylate of formula (I).
  14. The method as defined in any of previous claims 1-13, wherein the aqueous solution of organic ammonium carboxylate of formula (I) is additionally admixed with compounds selected from the group comprising glycols, preferably ethylene glycol or propylene glycol, glycerols and viscosity modifying polymers, so that said aqueous organic ammonium carboxylate composition contains 5 to 97.5 wt-% of water.
  15. The method as defined in any of the previous claims 1-14, wherein aqueous solution of organic ammonium carboxylate of formula (I) is additionally admixed with auxiliary substances such as additional corrosion inhibitors, biocides, fragnance(s), coloring agents, surfactants, and viscosity intensifiers, so that the concentration of auxiliary substances will be in the range of 0.001 to 10 wt-% from the total weight of aqueous solution.
  16. The method defined in any of previous claims 1-15, wherein the aqueous solution of organic ammonium carboxylate of formula (I) contains formic acid, acetic acid and monoethanolamine or trimethylmonoethanolamine.
  17. The method defined in any of the previous claims 1-16, wherein aqueous solution of organic ammonium carboxylate of formula (I) is used 1-2 l per 1000 kg of crushed stone, preferably 1.2 -1.5 l per 1000 kg of crushed stone.
  18. The method defined in any of the previous claims 1-17, wherein freezing point of said aqueous solution of organic ammonium carboxylate of formula (I) is from -3 °C to -15 °C preferably from -5 °C to -10 °C.
  19. The method defined in claim 1, further including a step wherein the solution comprising aqueous organic ammonium carboxylate of formula (I) is prepared by mixing, in situ, an aqueous solution of 1- 5 wt-% of amine with an aqueous solution of 1- 5 wt-% of acid.
  20. The method defined in claim 1 in which drops of aqueous ammonium carboxylate solution drops to have average diameter of 40 -500 um (0,4 -5 mm).

Description

FIELD OF INVENTION The invention relates to the method of preamble of claim 1. The invention relates also to the combination of mist or drops of an aqueous solution of organic ammonium carboxylate of formula (I) and fine material of preamble of claim 21 The invention relates to method for spraying an aqueous solution of organic ammonium carboxylate in controlling dusting of sand, crushed stone, , crushed expanded clay, or crushed expanded clay aggregate, crushed cement or concrete, or chopped organic material. The organic ammonium carboxylate which is used as an aqueous solution is especially adapted for controlling dust formation in applications where the biodegradation and low BOD is also required. Preferably it is used the environmentally benign freezing point depressant compositions for preventing dust formation and for preventing ice formation (anti-icing) within the compositions itself. BACKGROUND OF INVENTION Mineral dust and street dust (from street rubble) are serious health problems for example in mining industry and cities. There are also other applications wherein dusting of sand, fine crushed stone and soil will cause mineral dust which is a serious health problem. Dusting causes also damage to equipment and vehicle used for example in mining industry, these include vehicles, electric motors, transport bands etc. Specifically in mining industry mineral, dust will intrude itself into ore silos and transportation vehicles and in mining equipment causing freezing in winter time. It has suggested several ways to reduce mineral dust in mining industry. One alternative is to bind mineral dust by means of aqueous or water-borne solutions. However, none of water-borne solutions have been successful this far. If an aqueous solution is used in dust control, water have a tendency to evaporate after been sprayed onto surface of crushed stone, sand or soil. This requires usage of relatively big amounts of aqueous solution. Using plenty of water in binding dust will then cause other problems, such as mineral puddling. One important aspect when using aqueous solutions in controlling mineral dust is possible disturbances brought into mining industry processes alongside with said aqueous solution: especially chlorides of potassium, magnesium, calcium and sodium have a tendency to cause disturbances in ore recovery processes, for example in extraction stages. One important aspect is also biodegradativity of solutions used for controlling mineral dust. Additionally using aqueous solutions to dust binding may also cause freezing of aqueous solution itself. Freezing point depressant compositions are used wide-spreadly for variety of purposes, especially for lowering freezing point of an aqueous system so that ice cannot be formed on surfaces or within the aqueous systems or for melting ice formed in those aqueous systems. However dust control with freezing point depressant compositions are relative rare because the effectiveness of the freezing point depressant compositions depends on the molar freezing point lowering effect, the number of ionic species that are made available and to the degree to which the compositions can be dispersed in the liquid phase. Most freezing point depressant compositions are either based on salts such as sodium chloride or potassium formate or alcohols such as glycols and methanol. Alkali and alkali-earth metal salts of carboxylic acid such as potassium formate, sodium formate, potassium acetate and sodium acetate have found increasing use in the area of deicing mainly due to their low environment impact and low viscosity at minus temperatures. However, using these compositions for controlling dusting in mining industry is not a viable option, because potassium, natrium, magnesium and calcium chlorides may interfere ore recovering process. GENERAL DESCRIPTION OF THE INVENTION The above prior art as a starting point, the objection of the present invention was to solve or at least to alleviate above mentioned problems. Thus, the general objection of the present invention was to provide an aqueous solution which could be used as a combined freezing point depressant and an aqueous solution for controlling dusting and which is also environmentally benign and which do not form chlorides which may interfere mining process. The ideal dusting control agent and freezing point depressant composition adapted to use for mining industry would have following properties: it should prevent effectively formation of mineral dust from grounded stones, sand and soil,it should be free of mining process disturbing halides such as chlorides of alkali and alkali-earth metals especially chlorides of potassium, sodium, magnesium and calcium,it should have relatively low biological (BOD) and chemical oxygen demand (COD),it should be effective at low temperatures, i.e. it should have low viscosity and low freezing point,it should not cause mineral puddling, that is, it should be effective when used also as relativ