WO2014166400A1

WO2014166400A1 - Sludge or soil treatment method and heavy metal content stabilization agent

Info

Publication number: WO2014166400A1
Application number: PCT/CN2014/075040
Authority: WO
Inventors: 大石徹
Original assignee: 阿酷尔商贸（上海）有限公司
Priority date: 2013-04-10
Filing date: 2014-04-10
Publication date: 2014-10-16
Also published as: CN104098237A; TW201439012A

Abstract

Provided in the present invention is a method for stabilization treatment of heavy metal contents in a sludge. The method employs a heavy metal content stabilization agent constituted by at least one acid salt of a metal selected among iron, zinc, copper, manganese, and aluminum and by either at least one alkali metal selected among calcium, magnesium, sodium, and potassium, or a basic compound of the alkali metal for stabilization treatment of the heavy metal contents in the sludge. The mixing ratio of the heavy metal content stabilization agent and the sludge is: 100 parts by weight of the sludge correspond to 0.5 to 30 parts by weight of the acid salt of the metal and 0.5 to 60 parts by weight of the alkali metal or the basic compound of the alkali metal. Use of the method of the present invention allows for simple stabilization treatment of hazardous contents such as traces of lead and other heavy metals contained in a factory-generated sludge, thus allowing the treated sludge to be used for landfill and other purposes, as the heavy metal hazardous contents in the treated sludge do not dissolve out of the sludge, the environment is thus protected.

Description

Sludge or soil treatment method and heavy metal component stabilization agent

The present invention relates to a sludge or soil treatment method and a heavy metal component stabilization agent, and more particularly to a method for safely using a sludge or sludge soil containing a heavy metal component produced in a factory or the like for landfilling. And stabilizing the harmful substances such as arsenic, lead, cadmium, nickel, and chromium (hexavalent) contained in the sludge or sludge soil to make them insoluble and the heavy metal components used for the treatment are stable. Chemical agent. Background technique

In processes such as manufacturing, refining, surface treatment, and gold plating in factories, mines, and ironworks, waste liquids containing heavy metals are generated. Among them, the high-concentration waste liquid will be recycled and reused as a raw material, and the low-concentration waste liquid which is itself an impurity substance will be discharged as waste water. For heavy metal substances contained in wastewater, an alkaline agent, an oxidizing agent, etc. are generally added to the wastewater treatment process, and it is dissolved as a precipitate in water, then a coagulation material is added, and it is concentrated and precipitated by a precipitation concentrating device, and then subjected to pressure filtration. The machine is dehydrated, and the substance dehydrated by the concentrated precipitation is disposed of as sludge and disposed of. When the sludge is disposed of in a landfill or the like, in order to prevent contamination to the surroundings, it is necessary to solidify the harmful substances and stabilize them without elution. In order to maintain the workability during the treatment, a certain degree of construction is required. strength. When sludge containing heavy metals or soil contaminated with heavy metals is disposed of, it is necessary to stabilize the heavy metals contained in the sludge. It is well known that Che late can make heavy metals insoluble, but since it is used in the acidic to neutral range, if it is mixed with a cheap cement or the like in order to maintain its workability during processing, it does not dissolve. Performance will be reduced. Therefore, if the amount of the chelate added is increased, there is a problem that the processing cost increases. Summary of the invention An object of the present invention is to provide a sludge or soil treatment method capable of solving the above-mentioned problems of the prior art, which is capable of dissolving heavy metals, and a heavy metal component stabilization agent used for such treatment.

5〜60重量单位的碱金属或或例如0. 5〜60重量单位的碱金属或A method of stabilizing a heavy metal component in sludge or soil by using an alkaline compound of an alkaline earth metal.

The heavy metal component contained in the sludge or the soil is one containing at least one of arsenic, lead, cadmium, nickel, chromium (hexavalent), mercury, cerium, selenium, and cerium.

The present invention also provides a heavy metal component stabilizing agent comprising 0.5 to 30 parts by weight of an acidic metal salt, and 0.5 to 60 parts by weight of a basic compound of an alkali metal or alkaline earth metal.

The above acidic metal salt is preferably selected from the group consisting of ferric chloride, ferric nitrate, ferric sulfate, zinc chloride, zinc sulfate, copper chloride, copper nitrate, copper sulfate, manganese chloride, manganese sulfate, aluminum chloride and aluminum sulfate. At least one metal salt powder or 15 to 35% aqueous solution.

The basic compound of the above alkali metal or alkaline earth metal is from calcium oxide, calcium hydroxide, calcium silicate, magnesium oxide, magnesium hydroxide, sodium hydroxide, sodium silicate, potassium hydroxide, potassium silicate, iron ore slag And at least one powder selected from the cement.

The heavy metal component in the sludge or soil can be simply stabilized by using the heavy metal component stabilizing agent provided by the present invention for sludge or soil treatment or by using the sludge or soil treatment method provided by the present invention. The sludge or soil subjected to such stabilization treatment, even if wetted by rain or the like, does not elute the heavy metal components therein, and can safely treat the treated sludge or soil for disposal. detailed description

The sludge or soil treated by the present invention is mainly produced by chemical sludge, chemical processing, refining, surface treatment, gold plating, etc. in chemical plants, mines, smelters, ironworks, gold plating plants, etc. The sludge soil produced during the process. The heavy metal component contained in the sludge or the soil is one containing at least one of arsenic, lead, cadmium, nickel, chromium (hexavalent), mercury, strontium, selenium, tellurium, and the like. As the acidic metal salt used in the heavy metal component stabilizing agent of the present invention, ferric chloride, ferric nitrate, ferric sulfate, zinc chloride, zinc sulfate, copper chloride, copper nitrate, copper sulfate, zinc chloride or manganese sulfate can be used. , aluminum chloride, aluminum sulfate, etc., and more suitable for the use of environmentally friendly and low-cost ferric chloride, iron sulfate, aluminum chloride, aluminum sulfate. The iron salt at this time is preferably a divalent or trivalent salt. The iron salt and the aluminum salt are preferably a powder or a 15 to 35 _W t° solution. Further, if the moisture content of the treated sludge is high, it is preferably a powder.

The acid metal salt is selected from at least one of iron, zinc, copper, manganese, and aluminum. If a high-concentration acidic wastewater containing the above metal is obtained, there is an advantage that the wastewater can be directly used as a sludge treatment material. use.

As the alkaline salt of the alkali metal or alkaline earth metal used in the heavy metal component stabilizing agent of the present invention, calcium oxide, calcium hydroxide, calcium silicate, magnesium oxide, magnesium hydroxide, sodium hydroxide or sodium silicate can be used. Potassium hydroxide, potassium silicate, iron ore slag, cement, etc., and more suitable to use calcium oxide, calcium hydroxide, calcium silicate, magnesium oxide, sodium hydroxide, iron ore slag, cement which are easy to obtain and low in cost. The alkali salt of an alkali metal or alkaline earth metal is preferably added as a powder to sludge or soil. In addition, magnesium oxide and cement can also be used as a solidifying material for sludge or soil.

The sludge treated by the present invention contains 5 to 95% by weight of water. If the moisture content is too low, mixing with the heavy metal component stabilizing agent becomes difficult. If the content is too high, the obtained treated waste water contains water. The rate will become high, easy to flow, and low in operability. Further, the chemical reaction heat, water and heat of reaction of the acidic metal salt used in the present invention and the basic compound of an alkali metal or an alkaline earth metal can also be utilized to reduce the water content in the sludge to be treated. In this case, it is preferred to use a combination of magnesium sulfate or iron sulphate having high chemical reactivity with magnesium oxide or calcium oxide. Further, the alkali metal compound of the acidic metal salt and the alkali metal or alkaline earth metal may be separately added to the sludge, or may be added in advance by mixing the two into a drug by a powder mixing device.

The alkali metal, alkaline earth type of the weight of the unit is 0. 5~30 weight unit of acid metal salt and 0. 5~60 weight unit of alkali metal, alkaline earth type. A basic compound of metal. In addition, if the sludge contains a large amount of water, it is preferable to calculate the weight in terms of a solid form, and when the moisture content of the sludge is 20% or less, it can be directly used to calculate the weight.

The mixture of sludge or soil and heavy metal component stabilizing agent should be mixed for more than a few minutes using a mixing device to evenly mix the whole. The stabilized waste thus obtained, the acidic metal salt and the alkaline A basic compound of a metal or an alkaline earth metal chemically reacts in the sludge to form a metal hydroxide having a high activity, so that heavy metal ions contained in the sludge are adsorbed thereon to achieve insolubilization. That is, a high-pH alkali metal, an alkaline earth metal basic compound and a water-soluble acidic metal salt are mixed in the presence of water, and a hydroxide having a metal ion forms a precipitate due to a high pH value, and is water-soluble. The heavy metal component is firmly bonded or adsorbed by these formed hydroxides and becomes stable. Therefore, whether such stabilized waste (such as sludge) is piled outdoors or used for landfill, the harmful components of heavy metals in the waste are not dissolved from the waste, thereby protecting the environment.

Hereinafter, specific embodiments will be described.

In each of the following examples (Examples 1 to 8), the sludge containing heavy metals was used as a dehydrated viscous material (water content: 45%) (sludge 1) produced in a wastewater treatment process of a chemical plant. The acidic metal salt added to the sludge 1 can be used from ferric chloride, ferric nitrate, ferric sulfate, zinc chloride, zinc sulfate, copper chloride, copper nitrate, copper sulfate, zinc chloride, manganese sulfate, chlorination. One or two or more selected from the group consisting of aluminum and aluminum sulfate, and a more environmentally friendly and low-cost ferric chloride, iron sulfate, aluminum chloride, or aluminum sulfate can be used. Specifically, according to the addition amount shown in each of the examples in Table 1, commercially available A1 ₂ (S04) ₃ , A1C1 ₃ , FeS0 ₄ , or FeCl ₂ reagents as acidic metal salts are added, and as a basic compound. The commercially available MgO, CaO, c _a (0H) ₂ reagents were mixed with a mixer for 10 minutes.

The obtained stabilized sludge was left to be moisturized for one day, and then subjected to a dissolution test in accordance with a general method. The results are shown in Table 1.

Table 1

Acidic metal FeS0 ₄ FeCl ₂

Salt addition 3 3

(Wt%)

Alkaline compounding Ca (OH) 2 CaO

Salt addition 3 3

Quantity (wt%)

Pb dissolution amount 0.21 0.004 0.00

(mg/L) 3

Further, in each of the following examples (Examples 9 to 16), the sludge containing heavy metals used a dehydrated viscous material (water content: 40%) (sludge 2) produced in the surface treatment process of the metal processing plant. In the sludge 2, a commercially available A1 ₂ (S0 ₄ ) ₃ , A1C1 ₃ , FeS0 ₄ , or FeCl ₂ reagent as an acidic metal salt is added according to the addition amount shown in each of the examples in Table 2, and A commercially available MgO, CaO, Ca(0H) ₂ reagent as a basic compound was mixed with a mixer for 10 minutes.

The obtained stabilized sludge was left to be moisturized for one day, and then subjected to a dissolution test in accordance with a general method. The results are shown in Table 2.

Table 2

Basic compound CaO Ca (OH) 2 CaO

Salt addition 20 20 60

(Wt%)

Ni dissolution amount 5.0 <0.05 <0.05 <0.05

(mg/L)

Cr ^3⁄4 dissolution amount 0.48 <0.02 <0.02 <0.02

(mg/L)

Further, in each of the following examples (Examples 17 to 23), the sludge containing heavy metals was used as a dehydrated viscous material (water content: 49%) (sludge 3) produced in a wastewater treatment process of a chemical plant. In the sludge 3, commercially available A1 ₂ (S0 ₄ ) ₃ , A1C1 ₃ , FeS0 ₄ , or FeCl ₂ reagents as acidic metal salts were added according to the amounts shown in the respective examples in Table 3, and A commercially available MgO, CaO, Ca(0H) ₂ reagent as a basic compound was mixed with a mixer for 10 minutes.

The obtained stabilized sludge was left to be moisturized for one day, and then subjected to a dissolution test in accordance with a general method. The results are shown in Table 3.

table 3

Further, in the following examples (Examples 24 to 29), the soil containing heavy metals used contaminated soil (water content: 26%) generated in the site of the chemical plant. In the contaminated soil, a commercially available A1 ₂ (S0 ₄ ) ₃ reagent as an acidic metal salt, and a commercially available MgO reagent as a basic compound were added in accordance with the amounts shown in the respective examples in Table 4. And mix with a mixer for 10 minutes.

The obtained stabilized contaminated soil was left to be moisturized for one day, and then subjected to a dissolution test in accordance with a general method. The results are shown in Table 4.

Table 4

Contaminated soil Example 24 Example 25 Example 26 Example 27 Example 28 Soil

Acidic gold A1 ₂ (S0 ₄ ) ₃ A1 ₂ (S0 ₄ ) ₃ A1 ₂ (S0 ₄ ) ₃ A1 ₂ (S0 ₄ ) ₃ A1 ₂ (S0 ₄ ) ₃ is a salt addition 0.15 0.25 0.5 10 20 Addition (wt

%)

Alkalinization MgO MgO MgO MgO MgO salt 0.35 0.75 1.5 30 20

(Wt%)

As dissolution 0.06 <0.001 <0.001 <0.001 <0.001 <0.001

(mg/L)

Contaminated soil Example 29

Soil

Acid gold A1 ₂ (S0 ₄ ) ₃

Salt Addition 30

Add amount (wt

%)

Alkaline MgO

Salt 60

Add amount

(Wt%)

As dissolution 0.06 <0.001

Inside

(mg/L) Also. In the sludge or contaminated soil used in the following examples (Examples 30 to 37), a commercially available FeS0 ₄ or A1 ₂ (S0 ₄ ) ₃ reagent as an acidic metal salt, and a basic compound were added. a commercially available MgO, or Ca(0H) ₂ reagent or a calcium silicate powder containing Tobermorite (C _ai . [Si ₁₂ 0 ₃₁ (0H) ₆ ] 8H ₂ 0) as a main component. The adsorbent material was prepared by mixing in advance with the mixing ratio shown in Table 5 by a powder mixing device sold in the market, and the above adsorbent material was added in an amount as shown in each Example of Table 5, followed by mixing for 10 minutes in a mixer.

The obtained stabilized sludge was left to be moisturized for one day, and then subjected to a dissolution test in accordance with a general method. The results are shown in Table 5.

table 5

Hereinafter, a comparative example will be described. The sludge containing heavy metals was the same as the sludge 1 used in Examples 1 to 8, and the amount of addition in the sludge according to each comparative example (Comparative Examples 1 to 7) in Table 6 was used. The same acidic metal salt as used in Examples 1 to 8 (a commercially available A1 ₂ (S0 ₄ ) ₃ , A1C1 ₃ , FeS0 ₄ , or FeCl ₂ reagent) and a basic compound (marketed MgO, CaO, Ca (0H) ₂ reagent), and mixed with a mixer for 10 minutes.

The obtained stabilized sludge was left to be moisturized for one day, and then subjected to a dissolution test in accordance with a general method. The results are shown in Table 6.

Table 6

In addition, as the sludge containing heavy metals, the same sludge as the sludge 3 used in Examples 17 to 23 was used, and the sludge was added in accordance with the comparative examples (Comparative Examples 8 to 13) in Table 7. The same amount of acidic metal salt as used in Examples 1 to 8 was added (A1 ₂ (S0 ₄ ) ₃ , A1C1 ₃ , which are commercially available, FeS0 ₄ , or FeCl ₂ reagent) and a basic compound (a commercially available MgO, CaO reagent) were mixed for 10 minutes with a mixer.

The obtained stabilized sludge was left to be moisturized for one day, and then subjected to a dissolution test in accordance with a general method. The results are shown in Table 7.

Table 7

Claims

5〜60重量单位的碱金属或或例如0. 5〜60重量单位的碱金属或An alkaline compound of an alkaline earth metal to stabilize heavy metal components in sludge or soil.

The sludge or soil treatment method according to claim 1, wherein the acidic metal salt is from ferric chloride, iron nitrate, iron sulfate, zinc chloride, zinc sulfate, copper chloride, copper nitrate, sulfuric acid. A metal salt powder of at least one selected from the group consisting of copper, manganese chloride, manganese sulfate, aluminum chloride, and aluminum sulfate or a solution of 15 to 35 wt%.

The sludge or soil treatment method according to claim 1, wherein the alkaline compound of the alkali metal or alkaline earth metal is derived from calcium oxide, calcium hydroxide, calcium silicate, magnesium oxide, magnesium hydroxide, At least one powder selected from the group consisting of sodium hydroxide, sodium silicate, potassium hydroxide, potassium silicate, iron ore slag, and cement.

The sludge or soil treatment method according to any one of claims 1 to 3, characterized in that the heavy metal component contained in the sludge or the soil contains at least arsenic, lead, cadmium, nickel, chromium (hexavalent ), one of the ions of mercury, strontium, selenium, and strontium.

, a heavy metal component stabilizing agent for treating sludge or soil, comprising 0.5 to 30 parts by weight of an acid metal salt, and 0.5 to 60 parts by weight of an alkali metal or alkaline earth metal basic compound.

The heavy metal component stabilizing agent for treating sludge or soil according to claim 5, wherein the acidic metal salt is from ferric chloride, ferric nitrate, ferric sulfate, zinc chloride, zinc sulfate, or chlorine. A metal salt powder of at least one selected from the group consisting of copper, copper nitrate, copper sulfate, manganese chloride, manganese sulfate, aluminum chloride, and aluminum sulfate or a 15 to 35% aqueous solution.

The heavy metal component stabilizing agent for treating sludge or soil according to claim 5, wherein the alkaline compound of the alkali metal or alkaline earth metal is derived from calcium oxide, calcium hydroxide or calcium silicate. At least one powder selected from the group consisting of magnesium oxide, magnesium hydroxide, sodium hydroxide, sodium silicate, potassium hydroxide, potassium silicate, iron ore slag, and cement.