NO875499L - NEUTRALIZATION AND STRENGTHENING DANGEROUS ALKALISM SOIL. - Google Patents

Description

The present invention relates to new mixtures and new methods in their use for the neutralization and purification of dangerous acid spills and spills.

Various mixtures are previously known for the purification of hazardous organic waste materials. Some earlier references describe methods for neutralizing acid spills. Several references describe mixtures for the neutralization and solidification of liquid waste, particularly raw sewage. However, these previously known mixtures and methods for neutralizing acidic waste will have several disadvantages.

US Patent No. 3,994,821 relates to the control and cleanup of mineral oil spills using a granular mixture

containing 36.5 - 47.5 wt# ground marble, 35 - 45.5 wt$ granular sodium carbonate, 16.5 - 21.5 wt$ granular magnesium oxide and 0.008 - 0.012 wt& of a suitable normal solid pH indicator. Painted marble pieces consist of calcium carbonate. The granular spill control mixture according to this patent is used to control and clean up substantially all spilled mineral acid by applying the granular mixture to the spill surface from the outer edge of the spill inwards and in an amount sufficient to absorb all the spilled acid. Although the game is generally neutralized by this granular mixture, acids with a high heat of neutralization may not be completely neutralized and will thus still represent a hazard. Furthermore, this method of applying the mixture would necessitate exposure of the workers to the spill. US patent no. 4,210,460 relates to a mixture for controlling and cleaning spills of hydrofluoric acid. This mixture can be in one of two forms:

an aqueous solution and a powdery mixture.

The aqueous solution consists of 20 - 29 weight of calcium acetate and 71 - 65 weight of water.

The powdery mixture consists of 99.90 - 99.99% by weight of powdered magnesium oxide and 0.01 - 0.1% by weight of a suitable normally solid pH indicator. The powdered magnesium oxide mixture can be sprinkled on the flux-acid spill. The pH indicator will indicate by color change when an essentially safe pH condition has been achieved. This mixture also has the disadvantages of less than total neutralization and consequent risk of exposure to the spill.

US patent no. 4,207,116 describes a granular absorbent material consisting of cement, an inorganic water-absorbing swelling agent, sand or ground stone, water and any dyes and other additives. The ingredients are mixed to give a paste which is allowed to solidify and the solidified material is dried and annulated. The cement solidifies with the water and acts as a skeleton-forming component that gives the hair to the granulated material. The sand or ground stone material acts as an inert mixing agent to lower the price of the granulated material. The water-absorbing, swelling agent which can be a clay facilitates the absorption of liquids such as water, oil and absorbs odors. All types of clay can be used as inorganic swelling agents, such as sepiolite, montmorillonite, kaolin, diatomaceous earth and bentonite. This mixture is intended to be used in cat "toilet" for the purpose of absorbing, neutralizing and solidifying dangerous acid spills.

US patent no. 3,980,558 relates to a method for removing liquid or semi-liquid waste containing soluble organic materials, retaining the waste and a solidifying agent consisting of a hydraulic cement which will harden on standing to a cohesive stone-like solid consistency. This prevents leaching of the waste. The term "hydraulic cement" refers to all mixtures of lime, silica and aluminum oxide or lime and magnesium oxide, silica, aluminum oxide and iron oxide and other mixtures of similar ingredients. A particularly preferred mixture is Type 1 "Portland Cement". The patent states that the method according to the invention is particularly useful for removing aqueous sludge waste from chemical processes for the production of phosphoric acids, especially water filters and sludge, which normally contain high levels of arsenic and dissolved arsenic compounds, as well as hydrogen sulphide and other sulfur compounds. Although this mixture tends to solidify the waste, it is not necessarily a neutralizing mixture. Furthermore, solidification is required when mixing with waste material, this is impractical when there has been a spill, which is not suitable for mixing.

US patent no. 4,518,508 describes a method for treating anhydrous liquids and semi-liquid waste by solidification. The method according to the described invention requires a dry water-reactive solidified agent comprising cement, a dry water-absorbing material and a powdery alkali metal silicate sufficient to convert the mixture into a consolidated, chemically and physically stable solid product and is added to the aqueous liquid or semi-liquid waste. The waste can then solidify and harden to form a synthetic, rock-like material. This mixture works to partially neutralize the acidic part in the waste. However, it will not provide complete neutralization. Another disadvantage is that it has to be mixed with the waste.

US patent no. 4,547,290 describes a method for solidifying strongly acidic or alkaline liquid waste. According to this patent, clays can be used directly in very acidic or strongly alkaline aqueous waste to enable the waste to be transformed into stable solid materials. According to this invention, clay material is dispersed in the waste by stirring and the waste is neutralized. A hydraulic and/or calcium binder then follows. All types of fresh or dried clays are used as well as pure clays, mixtures including attapulgite and metal carbonates. During the neutralization process, lime, ground limestone, calcium carbonate base waste, calcium silicate and/or aluminates can be added, especially to acidic waste. The third step of the process causes the material to be able to solidify. Materials such as Portland cement can be added to the paste-like mass that is formed. Again, the mixture must be mixed to form a slurry to neutralize and solidify the waste, necessitating close contact with the waste. This method is therefore impractical when applied to acidic games.

US Patent No. 3,837,872 describes an aqueous solution of an alkali metal silicate mixed with waste material and a silicate curing agent which causes the silicate and waste material to react with each other. This invention relates in particular to the treatment of raw human waste. According to the invention, the waste is mixed with an alkali metal silicate such as sodium silicate, which in the presence of a silicate curing agent causes the mixture to undergo consolidation and solidification. The curing agents include acids or acidic materials which cause gelatinization of the silicate. The hardener includes Portland cement, lime, gypsum and calcium carbonate and aluminium, iron, magnesium, nickel, chlorine, manganese or copper compounds. This method also suffers from the disadvantage that it requires close contact with the waste for solidification as well as the mixture in question. This procedure cannot be used for game control.

US Patent No. 4,297,304 describes a method for solidifying high and medium radioactive and/or actinidine-containing aqueous concentrates for fine-grained solid waste suspensors in water for final non-polluting storage. The waste concentrates or suspensions are hardened by evaporation to give an evaporation product with a water content in the range of 40 - 80% by weight and a solids content of a metal, iron and/or metal oxide component in the range of 10 - 30% by weight of the evaporated product. The clay-like constituents include silicate, alumina and Portland cement. The metal oxides may include MgO. The pH of the evaporated product is adjusted to between 5 -10 and kneaded with a clay-like component Containing a small amount of cement or mixing a clay-like component with a small amount of cement containing additives to suppress the volatility of alkalis. Molded bodies are then produced from the kneaded mass, heat treated and calcined and fired. The bodies are then enclosed on all sides in a dense, continuous ceramic or metallic matrix. The known methods are thus burdened with several disadvantages when these are applied to dangerous acid spills. A mixture which can neutralize several types of acids and which can be applied from a safe distance without danger to the workers is not proposed according to the state of the art.

The present invention is directed to new mixtures and methods for using the mixtures to neutralize and solidify dangerous organic spills so that the spread of such spills during the neutralization and solidification is substantially prevented. The mixture and the method according to the invention can be used from a safe distance and limit the rate of neutralization. Thus essentially all of the game is allowed to react and neutralize. The new mixtures according to the invention contain the following: 0-80 wt# alkaline earth metal oxide, 0-30 wt# alkali metal carbonate, 0-10 wt# highly absorbent silica or clay, 5-30 wt$ less absorbent clay, 0.5-2 wt$ hydrophobic lubricant and 10 - 50 wt.lb Portland cement.

The alkaline earth metal oxides that can be used in the present mixtures include, for example, magnesium oxide and calcium oxide. These components serve as neutralizing agents for the dangerous acid spills to be treated.

Portland cement is a form of magnesium oxide that is highly reactive and serves to neutralize acidic components in dangerous acid spills. It can, for example, neutralize less reactive acids.

The alkali metal carbonate compounds used in the mixture according to the invention also act as neutralizing agents. Preferably, potassium carbonate or sodium carbonate is used. These compounds also act as solubilizing agents to maintain the solubility of the neutralizing bases. Bicarbonates and sesquicarbonates can also be used in the mixtures for these purposes. Highly absorbent silicas or clays such as calcium silicate are used in the mixtures according to the invention as fibrous absorbents. Calcium silicate absorbs very large amounts of liquid in relation to its weight. Silicas and clays can also be used as absorbents. These absorbents facilitate the neutralization reaction by absorbing some of the less acidic material during neutralization. This allows the neutralization water to effect complete neutralization. Therefore, essentially all of the acid will be neutralized and solidify instead of only the most reactive acids. Another absorbent clay with a slower absorption rate than the absorption for the calcium silicate group, such as attapulgas clay, is preferably also used in the mixture according to the invention. Roaming clay and perlite are other examples of less absorbent clays. By varying the acceptance rate as a result of the different clays present in the mixture, the neutralization rate for unabsorbed acids can be increased. When more of the reactive acids have been neutralized and the products absorbed, the less reactive acids will desorb and react with the remaining base. This allows the neutralization reaction to be constantly driven towards completion, without reaching equilibrium. This is due to the varying availability of the reactants. A small amount of a hydrophobic lubricant such as magnesium stearate, sodium or aluminum stearates, tricalcium phosphate, octates and the like can be added to the compositions to make the powders according to the present composition free-flowing. The lubricant acts as a lubricant by providing hydrophobicity to the particles and preventing them from sticking together. The mixture according to the invention contains several reactive grades of alkaline materials, for example magnesium oxide. This allows a controlled and complete neutralization reaction. This allows the mixtures according to the invention to be used to neutralize a large number of acids, each of which may have different energy requirements for neutralization. When using the mixtures in the present invention, more reactive acids will be neutralized quickly and thus generate neutralization heat which, in turn, will facilitate the neutralization of less reactive materials. The presence of varying reactive degrees of magnesium oxides will allow this to happen gradually. An example of a preferred mixture in the present invention is as follows: 73.79 wt% MgO, 5 wt% Na2CO3, 10 wt% CaO, 5.5 wt% attapulgas clay, 5.12 wt% calcium silicate and 0.5 wt% magnesium stearate . 7.5 liters of this mixture of this mixture can neutralize 12 - 13.6 liters of sulfuric acid and raise the pH to 7.3. Among other things, it can also neutralize hydrochloric acid, nitric acid, phosphoric acid, terchloric acid, acetic acid and hydrofluoric acid. The mixtures according to the invention are preferably applied to the dangerous spill by means of a fire-extinguishing apparatus similar to tubs. They are preferably applied in dry form in which they are also stored. They can be stored under pressure in a storage chamber until they are used and/or pressurized using an external gas through an external propellant gas cartridge. The size distribution of the particles of the present compositions allows them to be applied to the game in a "soft" pattern, that is, relatively dispersed in such a way that they will cover the game when spread without splattering the game and without endangering anyone. The mixtures should be applied at a distance of approx. 3 - 4.5 m and the nozzle speed should be in the range 9 - 15 m/s. To achieve this speed, the particles should have a particle size distribution between -40 and 200 Tyler sieve size. The powdery mixtures according to the invention can be applied in a nitrogen gas stream. The specially specified particle size distribution will essentially ensure a suitable flow rate and delivery pattern. The application method according to the invention allows control and neutralization of hazardous spills from a distance without causing splashing of hazardous materials during neutralization. The following examples illustrate the compositions and methods according to the invention.

Examples

The following mixtures were prepared and tested to determine their suitability for the present process in the following manner.

About. 7.5 1 acid was mixed with approx. 12 - 13.6 of the mixture. The mixture/acid mixture was then mixed together and allowed to undergo a neutralization reaction. Then 10 g of the mixture was diluted with 100 ml of deionized water and the pH was measured. The mixture A - R indicated below was investigated in this way. The mixtures A - R are described according to the weight share of each component. The designation 20 x 100 indicates the particle size distribution of MgO in the same way as "Fine Grade-100". The term "atta clay" indicates attapulgus clay "silanox" is a silicon containing material available from Cabot Co, Boston, Mass.

The results of the experiments are shown in Table 1. Table 1 indicates, from the left, the sample number, the mixture used, the volume of acid neutralized, the initial weight of the mixture before carrying out, the final weight of the mixture actually carried out, the percentage of the mixture that was carried out, initial pH and final pH of the mixture/acid mixture and observations regarding the sample itself. The percentage of mix performed indicates the ability of the mix to be effectively dispersed on the game. The difference in pH from the initial to the final reading indicates the ability of the mixture to neutralize the game. Table 1 shows that the mixtures according to the invention have an excellent ability to absorb and neutralize acidic spills. They can also be easily dispersed all over the game from a given distance.

MIXTURES

Mixture A: 73.39 wt# MgO (20 x 100)

10.00 wt# CaO

5.00 wt# Na2C03(dense) 5.21 wt5é CaSi03

5.50 wt% attal clay - coarse 0.50 wt$ Mg stearate

Mixture B: 73.79 wt% MgO (20 x 100)

10.00 wt£ CaO

10.00 wt£ Na2C03dense 5.71 wt£ CaSI03

0.50 wt. Mg stearate

Mixture C: 65.00 wt£ MgO (20 x 100)

5.00 wt% MgO (10 - 40)

15.26 wt£ CaO

5.00 wt$ Na2C03-dense 4.00 wt% attal clay - coarse 5.21 wt£ CaSi03

0.50 wt£ Mg stearate

Mixture D: 62.50 wt£ MgO (20 x 100)

10.00 wt£ Mg Chem (10 - 49) 10.26 wt£ CaO

5.00 wt£ Na2C03-dense 4.03 wt$ attal clay - coarse 7.71 wt5é CaSi03

0.50 wt# Mg stearate

Mixture E: 73.79 wt.lb MgO (20 x 100)

10.00 wt£ CaO

5.00 wt.lb Na2C03 dense 5.50 wt.lb attal clay 5.21 wt.lb CaSi3

0.50 wt$ Mg stearate

Mixture F: 39.00 wt£ MgO (20 x 100)

39.00 weight SÉ MgO- ("Fine Grade-100")

9.00 wt# Na2C03- dense

10.00 wt$ attal clay - coarse 3.00 wt# Mg stearate

Mixture G: 79.00 wt# MgO (20 x 100)

10.00 wt£ CaO

10.00 wt£ attal clay - coarse 1.00 wt£ tricalcium phosphate

Mixture H: 39.00 wt£ MgO (20 x 100)

39.00 wt£ MgO ("Fine Grade-100")

9.00 wt£ Na2C03- dense

10.00 wt# attal clay - coarse 3.00 wt$ tricalcium phosphate

Mixture I: 39.50 wt.lb MgO (20 x 100)

39.50 wt£ MgO ("Fine Grade-100") 10.00 wt# CaO

5.00 wt£ Na2Co3- dense 5.50 wt56 attal clay - coarse 0.50 wt# Mg stearate

Mixture K: 36.00 wt£ MgO (20 x 100)

36.00wt£ MgO ("Fine Grade-100") 20.00wt£ Na2C03- dense 5.00wt£ Attale clay - coarse 3.00wt£ Tricalcium Phosphate

Mixture L: 36.00 wt£ MgO (20 xl00)

36.00 wt£ MgO ("Fine Grade-100")

5.00 wt£ CaO

10.00 wt£ Na2C03- dense 10.00 wt# attale clay - coarse 2.50 wt% tricalcium phosphate 0.50 wt# silanox

Blend M: £39.50 weight (20 x 100)

39.50 wt£ ("Fine Grade-100") 8.00 wt# CaO

5.00 wt$ Na2C03- dense 5.00 wt$ attal clay - coarse 3.00 wt% tricalcium phosphate 0.50 wt# silanox

Mixture N: 49.00 wt£ MgO (20 x 100)

29.00 weight5é MgO ("Fine Grade-100")

9.00 wt$ Na2C03- dense

10.00 wt% attal clay - coarse 3.00 wt$ magnesium stearate

Mixture P: 36.50 wt% MgO (20 x 100)

36.50 wt£ MgO ("Fine Grade-100") 5.00 wt% CaO

9.00 wt£ Na2C03- dense

12.50 weight $ attal clay - coarse 0.50 weight see magnesium stearate

Mixture Q: 36.50 wt£ MgO (20 x 100)

36.50 wt£ MgO ("Fine Grade-100") 5.00 wt£ CaO

9.00 wt£ Na2C03- dense

12.50 weight5é attal clay - coarse 0.50 weight$ magnesium stearate

Mixture Q: 31.50 wt£ MgO (20 x 100)

31.50 wt£ MgO ("Fine Grade-100") 4.00 wt£ CaO

7.50 wt$ Na2C03- dense

25.00 wt$ attal clay - coarse 0.50 wt% magnesium stearate

Sample sieve distribution for the different mixtures is shown in Table II. Distribution may vary somewhat according to the particular example. The mixture is indicated on the left. The column labeled "Bulk" indicates the medial size of the powder. The designation "Sieve" indicates the size of the sieve used to determine the particle size.

Claims (9)

1. Mixture for neutralization and solidification of dangerous acid spills, characterized in that it consists of 1 - 8 wt# alkaline earth oxide, 0-30 wt# alkali metal carbonate, 0-10 wt$ highly absorbent silica or clay, 5-30 wt# less absorbent clay , 0.5 - 2 wt# of a hydrophobic lubricant and 0 - 50 wt# of Portland cement. 2. Mixture according to claim 1, characterized in that it consists of magnesium oxide, calcium oxide, sodium carbonate, attapulgas clay, calcium silicate and magnesium stearate. 3. Mixture according to claim 1, characterized in that the magnesium oxide is present in coarse and fine graded forms. 4. Mixture according to claim 1, characterized in that it consists of approx. 94 weight see magnesium oxide, approx. 10 weight see calcium oxide, approx. 5 wt% sodium carbonate, approx. 5 weight# calcium silicate, approx. 6.5 weight# of attapulgas clay and approx. 0.5056 magnes iums terat. 5. Mixture according to claim 1, characterized in that it consists of 31 - 39 g by weight. coarse grade MgO, 31 - 39 wt£ fine grade MgO, 5-9 wt$ sodium silicate, 5-10 wt# attapulgas clay and 1 - 3 wt$é tricalcium phosphate. 6. Mixture according to claim 1, characterized in that it consists of 31.5 wt% coarsely graded MgO, 31.5 wt% finely graded MgO, approx. 4 wt.5é CaO, approx. 7.5 wt$ Na2 C03 , approx. 25 weight 5é attapulgas clay and approx. 0.5 wt% magnesium stearate. 7. Process for neutralization and solidification of dangerous acid spills, characterized in that the spill is applied to a mixture consisting of 0-80% by weight of alkaline earth oxide, 0-30% by weight of alkali metal oxide, 0-10% by weight of highly absorbent silica or clay, 5-30% by weight # less absorbent clay, 0.5 -2 weight see hydrophobic lubricant and 0 - 50 weight See Portland cement and thus neutralize and solidify the play. 8. Method according to claim 7, characterized in that the application takes place by delivering the mixture onto the game under pressure using a nitrogen propellant gas from a fire-extinguishing delivery device. 9. Mixture according to claim 1, characterized in that in dry form the particles have a particle size distribution between -40 and 200 Tyler mesh size.