JP4016319B2 - Processing method of raw consludge into stable or stable type waste and its processed waste - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for processing raw consludge into a stable type or a waste according to the stable type and the processed waste.
[0002]
[Prior art]
Remaining suspended water (sludge water) from which fine aggregates and coarse aggregates are recovered from washing wastewater by washing mixers in the ready-mix factory and washing the remaining and return condensers in the agitator truck, or those dehydrated using a dehydrator This is called raw consludge and belongs to sludge in the handling of industrial waste.For example, it is only allowed to dispose of waste under strict control by building a concrete retaining wall in the ground and blocking it from penetrating into groundwater etc. It was. Recently, it is possible to change the designation of the raw consludge to a stable waste corresponding to glass and ceramic waste, as long as it is a solid product of raw consludge having the same performance as solidified mortar. If it is a stable type waste, for example, the waste can be treated simply by excavating the ground and reclaiming it.
[0003]
[Problems to be solved by the invention]
However, it is difficult to secure the same performance as mortar solidified with ordinary raw consludge, and after all it is currently treated as managed waste, and there are many problems such as securing disposal sites and disposal costs. Have In other words, it is difficult to secure a disposal site and there are many cases where it is illegally dumped in reality, which not only causes troubles with the residents in the vicinity, but also infiltrates into groundwater and causes environmental pollution. In addition, these ready-mixed sludge is usually processed by contracting a specialized industrial waste disposal company, and the cost required for dehydration, drying, transportation, etc. is higher than the production cost of ready-mixed concrete itself. The cost effectiveness of the construction company was significantly impaired. On the other hand, the sludge cake dehydrated on the same day when the remaining and returning condensate and washing wastewater are generated, and the water content adjusted to about 50% or less by a high-performance dehydrator is equivalent to the solidified mortar. Although it is known to obtain a hardened body of high-performance raw sludge, the target is limited to sludge cakes that are dewatered on the day, and a dehydrator for reducing the moisture content to about 50% or less is expensive. Could not be adopted.
[0004]
The present invention has been made in view of the above-described conventional problems, and the object of the present invention is to reduce raw consludge as waste, which cannot be practically constructed with special equipment or costly for processing. Can be processed as a hardened body of raw consludge with the same performance as solidified mortar without increasing the processing cost, and at the same time a stable or stable type of raw consludge that can prevent environmental pollution It is in providing the processing method to the waste according to JIS, and its processing waste.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a raw consludge stable type or a processing method for waste according to a stable type, wherein the sludge solid content of the raw consludge to be treated and moisture (included in the raw consludge) And a blast furnace slag fine powder body, and a blast furnace slag fine powder body with respect to the total mass fraction Sd, W, Sg of each of the main blend elements. The mass fraction is distributed so as to be set according to the relationship of the following formula (A), and the main blending element is 5 to 20 (with respect to the mass sum of the sludge solid content and the blast furnace slag fine powder obtained by the formula (A). The stable type of ready-mixed sludge is characterized by processing the ready-mixed sludge as a stable type or a waste conforming to the stable type by mixing and kneading a sub-mixing element consisting of waste gypsum (wt%). There is composed of a processing method of the waste according to the stable.
(Formula A) Sg = 100−W (1 + 1 / α) [wt%] {however, moisture content α = W / Sd}
[0006]
At this time, the mass fraction W of water is preferably set to 30 to 60 (wt%) with respect to the total mass fraction.
[0007]
More preferably, the mass fraction Sd of the sludge solid content is 15 to 25 (wt%), the mass fraction W of the water is 60 to 40 (wt%), and the mass fraction Sg of the blast furnace slag fine powder is 25 to 25%. It is good to set to 35 (wt%).
[0008]
In addition, the strength of the work piece corresponding to each mass fraction of the main blending element is set in relation to the formula (A), and a predetermined mass of waste gypsum mixed therein is fixed, and the main mass is fixed to each side of the triangle. Assign each element of the compounding element and place the mass fraction scale on each side, and do not exceed the target exceeding the predetermined strength at the intersection of parallel lines along the adjacent side It is good to make it discriminate | determine by the triangular component graph displayed distinguishing and object.
[0009]
Moreover, this invention is comprised from the processing waste according to the stable type | mold of the raw consludge processed by the processing method in any one of Claim 1 thru | or 4, or a stable type.
[0010]
Furthermore, the present invention provides the mass fractions Sd, W of the sludge solid content of the raw consludge to be treated, the moisture (including the water content and the amount of water contained in the raw consludge), and the blast furnace slag fine powder. The mass fraction of the ground granulated blast furnace slag is obtained from the following formula (A) with respect to the total of Sg, and 5 to 20 with respect to the sum of the solid content of the sludge solids and the ground granulated blast furnace slag obtained by the formula (A). (Wt%) waste gypsum added to each of the sludge solid content, water (including the water content and water content contained in the raw concrete sludge), and the blast furnace slag fine powder mass determined by the formula (A) It consists of a composition setting method of each element when processing as a waste according to a stable type or a stable type of raw consludge as a quantity. .
(Formula A) Sg = 100−W (1 + 1 / α) [wt%] {however, moisture content α = W / Sd}
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. The present invention comprises as a main blending element a group consisting of sludge solids of raw consludge to be treated, moisture (including water content and water content contained in the raw consludge), and ground granulated blast furnace slag. Distribute the mass fraction of the blast furnace slag fine powder to the total mass fraction Sd, W, Sg of the blending elements so that they are set according to a predetermined relational expression, and set them according to the predetermined relational expression to the main blending element A mixture of sub-preparation elements consisting of 5 to 20 (wt%) waste gypsum with respect to the mass sum of the sludge solid content and the blast furnace slag fine powder was mixed and kneaded, and the ready-mixed sludge conformed to a stable type or a stable type. It is to be processed as waste. In other words, raw consludge to be treated, water, blast furnace slag fine powder, and waste gypsum powder obtained from gypsum board waste material are the basic blending elements, of which raw consludge, water, blast furnace slag fines The relational expression between the respective mass fractions and the total mass fraction is set with the powder body as a main blending element, and further, 5 to 20 (with respect to the mass sum of the sludge solid content and the blast furnace slag fine powder body obtained thereby. The mixed raw sludge is treated as a processing waste by mixing and mixing a sub-preparation element made of waste gypsum (wt%) into the main preparation element. The mass fraction of each element of the main blending element can be uniquely obtained from the relational expression by setting the above-described waste gypsum mixed mass and the mass of any other element. By adding waste gypsum with a predetermined ratio to the total mass of sludge solids and ground granulated blast furnace slag, the corresponding mass fraction of the main blending element can be easily determined, thereby providing valuable resources. The amount of fine powder of blast furnace slag can be reduced, and a kneaded and solidified processed material that does not need to be crushed can be easily produced from raw consludge.
[0012]
In the raw blended sludge processing and blending material of the present embodiment, the substantial valuable material is only the blast furnace slag fine powder among the main blending element and the sub blending element. The raw water content of raw consludge varies greatly depending on the storage condition, but the water content has been reduced to some extent by sun drying or pneumatic simple dehydration. Even those with a rate can be processed. In addition, not only dehydration on the day, but also can be used in the same manner as long as the alkali amount is not reduced by carbonation by contact with outside air while remaining in the water tank.
[0013]
The blast furnace slag fine powder may be not only blast furnace slag fine powder but also blast furnace cement. In the experiment, a blast furnace slag fine powder having a specific surface area of about 6000 cm 2 / g is used in the experiment.
[0014]
The gypsum board waste material is, for example, one that has been crushed after separation of the surface paper, and preferably has a particle size of about 1.2 mm or less, but may be more or less. Further, the gypsum board waste material may be non-heated and the whole amount may be dihydrated gypsum, or may be half-hydrated gypsum by dry heating. Non-heated gypsum board waste material promotes the development of strength of raw hardened sludge work-hardened body by the production of ettringite by the reaction of dihydrate gypsum and blast furnace slag.
[0015]
As described above, in the present embodiment, the main blending element is considered to be a cured body composed of three components of sludge solid content, moisture (including the water content and water content of sludge), and blast furnace slag fine powder. And set the distribution of waste gypsum that can easily develop the strength of those hardened bodies, corresponding to each distribution amount of sludge solid content, moisture, mass fraction of blast furnace slag fine powder of the main preparation elements In order to produce a workpiece that has the desired strength as waste by measuring the compressive strength of the mixture of the main blending elements and waste gypsum in each blending distribution. Each mass fraction of can be known.
[0016]
The relational expression of the mass fraction of the blast furnace slag fine powder with respect to the sum of the mass fractions Sd, W, Sg of the sludge solid content, moisture, and blast furnace slag fine powder of the raw consludge in the main blending element is as follows: For example, it is set as Sg = 100−W (1 + 1 / α) [wt%] (formula A) in the formula for obtaining the blast furnace slag fine powder. FIG. 1 shows the relationship between each blending element. The mass fraction Sd (wt%) of the sludge solid content of the raw consludge and the water mass fraction W containing the water content and water content contained in the raw consludge ( wt%) and the mass fraction Sg (wt%) of the blast furnace slag fine powder body is 100 (wt%). The water content α is obtained by α = W / Sd obtained by dividing the water W by the sludge solid content Sd. From this relationship, the blending amount of the blast furnace slag fine powder Sg is determined by Sg = 100−W / α−W [wt%] formula (A-2). Specifically, the moisture content α is obtained by sampling and measuring, for example, a plurality of portions of the raw consludge to be treated, and by setting the moisture content, the necessary blast furnace slag fine powder together with the mass fraction of each element The amount of body is determined. In this case, each amount is set so that the consumption of raw consludge, which is a waste product, is increased within the range where the required compressive strength can be obtained, and the amount of blast furnace slag fine powder, which is a valuable resource at that time, is set to a small amount. You can decide the rate. From formula (A-2), it can be seen that it is better to set a larger amount of water for this purpose.
[0017]
A sub-mixing element composed of 5 to 20 (wt%) waste gypsum is mixed into the main mixing element and kneaded with respect to the total mass of the sludge solid content and the blast furnace slag fine powder obtained from the relational expression of the above main mixing element. To treat raw consludge as processing waste. This range is determined by experiment in consideration of the relationship of change in compressive strength due to waste gypsum mixing and the possibility of kneading with the main blending elements. And the mass fraction of each element which can ensure a desirable intensity | strength, reducing the amount of blast furnace slag fine powder as valuables as much as possible is determined, and, thereby, the processing waste of practical raw consludge can be manufactured.
[0018]
In order to know the strength of the workpiece corresponding to each mass fraction of the three components of the main blending element, a triangular component graph in which each element is assigned to each side of the triangle as shown in FIGS. 2 to 4 is effectively used. . This triangular component graph fixes the predetermined mass of waste gypsum set and mixed in relation to the formula (A), and the mass fraction scale of each element assigned to each side of the triangle is an equally divided scale. It is displayed on each side, and at the intersection of parallel lines along the adjacent side, a target exceeding the predetermined intensity and a target not exceeding are displayed separately. For example, in FIG. 3, when the mixing rate of waste gypsum (gypsum board waste material) is set to 10 wt% according to the distribution of FIG. 8, 20 ° C. underwater curing material has a compressive strength of 5 N / mm 2 or more after 7 days of age. Based on the specimen, those exceeding 5 N / mm 2 are indicated by circles, and those below are indicated by x. Thus, the relationship between the mass of the ground granulated blast furnace slag and the amount of water that can easily maintain a predetermined strength can be grasped schematically, and the practical convenience is particularly high.
[0019]
As shown in FIG. 3, the amount of the blast furnace slag fine powder having the compressive strength of 5 N / mm 2 or more is the smallest because the sludge solid content Sd = 20 (wt%) and the water W = This is a case of a combination of 60 (wt%) and blast furnace slag fine powder Sg = 20 (wt%). On the other hand, there is a combination of Sd = 5 (wt%), W = 25 (wt%), Sg = 70 (wt%), for example, having a strength of 5 N / mm 2 or more, but the strength is 31.3 N / Mm 2, and it becomes difficult to knead with other materials, and on the contrary, it is too hard to be used, and it becomes necessary to devise additional costs for crushing treatment, so that it cannot be employed. Eventually, by setting the mass fraction W of water to 30 to 60 (wt%) with respect to the total mass fraction, the amount of blast furnace slag fine powder used is kept at the lowest possible rate and at the desired strength. A range can be specified. In the example of FIG. 3, the strength at the time of various distributions of the main blending elements at that time is measured as the waste gypsum mixing rate 10 (wt%), but each specimen in the range of 5 to 20 (wt%). By creating and carrying out the above, it is possible to easily set specific mass fractions for almost all preparation modes. As a reference example, FIG. 4 is based on a specimen having a compressive strength of 5 N / mm 2 or more for a reference material having no waste gypsum mixed according to the formulation distribution of FIG. Those exceeding 5 N / mm 2 are indicated by a circle, and those less than 5 N / mm 2 are indicated by an x mark. In both cases, it was found that a minimum amount of blast furnace slag fine powder (50% by weight) was necessary to maintain a compressive strength of 5 N / mm 2 or more. It can be seen that the predetermined strength of the processing waste can be obtained by reducing the amount used.
[0020]
Specifically, in FIG. 3 and FIG. 8, the range in which kneading can be performed without using a water reducing agent is such that W is about 30% or more, and the compressive strength at 20 ° C. under water curing material age 7 days is 5 N / mm 2 or more. When gypsum board waste material is not mixed, W is about 40% or less, and when gypsum board waste material mixture rate is 10%, W is about 60% or less, and the moisture content α = W / Sd of raw consludge is measured. By the range, Sd = W / α and Sg = 100−W (1 + 1 / α), the mass fraction (%) of the sludge solid content and the blast furnace slag fine powder is obtained. Then, when the sludge cake T containing the sludge solid content Sd and the water W is used as the mass of the raw consludge to be actually processed, this T, that is, {Sd + W (wt%)} and the blast furnace slag fine powder Sg (wt%) are mixed. , T = Sd (wt%) × (1 + α), Sd (wt%) = T / (1 + α), and Sg (wt%) as X, (Sd + W): Sg = T: From X, the blast furnace slag fine powder The mass is obtained by T [Sg / (Sd + W)], and the mass of the gypsum board waste is the mass of the sludge cake {T / (1 + α)} and the mass of the blast furnace slag fine powder when the mixing rate is 10%. It is determined as 10% of the sum of {T [Sg / (Sd + W)]}. In this way, the formulation can be determined by the measured value of the moisture content of the raw consludge to be treated and the range of the water amount W in which the compressive strength is, for example, 5 N / mm 2 or more.
[0021]
More preferably, the mass fraction Sd of the sludge solid content is 15 to 25 (wt%).
The mass fraction W of water is preferably set to 60 to 40 (wt%), and the mass fraction Sg of the blast furnace slag fine powder is set to 25 to 35 (wt%). For example, in FIG. 8, in the combination of Sd = 20 (wt%), W = 50 (wt%), and Sg = 30 (wt%), the amount of blast furnace slag fine powder used is 30 (wt%). However, the compressive strength is 11.3 N / mm 2, and in this case, it is possible to dispose as not a managed waste but an officially certified stable waste. Stable waste has the same performance as solidified mortar, that is, raw consludge with a uniaxial compressive strength of 8 N / mm2 or more is recognized as stable waste as being equivalent to glass and ceramic waste. It is only necessary to perform the landfill process in the excavation hole without providing it, and the process is greatly simplified and the processing cost is low. Therefore, if raw consludge can be processed as stable waste and its processing cost is low, the economic burden on concrete manufacturers and construction companies is light, and as a result of proceeding with such processing, groundwater Environmental problems due to pollution and illegal dumping, and troubles with the surrounding residents are reduced, and problems related to the treatment of raw consludge can be solved at once.
[0022]
As described above, the gypsum board waste material of the waste gypsum as a sub-mixing element is constant in a mass ratio of 5 to 20 wt% with respect to the mass sum of the sludge solid content and the blast furnace slag fine powder, It is set and mixed as an outer ratio with respect to the mass sum of two elements of the main blending elements. The waste gypsum as a sub-mixing element increases the strength development and shrinkage reduction effect as the mixing ratio increases, but the moldability deteriorates due to a decrease in fluidity, and mixing with the main mixing element becomes difficult. From this point, the gypsum mixing rate is preferably 5 to 20 (wt%) with respect to the mass sum of the sludge solid content determined by the formula (A) and the blast furnace slag fine powder. FIG. 5 shows that the raw sludge mass fraction Sd = 22.5 wt%, the moisture mass fraction W = 57.5 wt%, the blast furnace slag fine powder Sg = 20.0 wt%, and the water curing at 20 ° C. It is a graph showing the relationship between the mixing rate of gypsum board waste material and the compressive strength for those with a material age of 3 days and those with the same age as 7 days, both of which compressive strength is proportional to the gypsum board waste material mixing rate of 10% When the mixing rate is 5%, the strength is already over 5N / mm2 at the age of 3 days, and the strength of about 8N / mm2 is secured in 10 days. It has been confirmed that when the gypsum contamination rate is 10% or more, the increase in compressive strength reaches its peak, and when the gypsum contamination rate is large, the short-term strength increases, but the expression of long-term strength is small. As can be seen from the graph of the relationship between the strength and the gypsum board waste material contamination rate for the ages of 7 and 28 days in FIG. 6, the gypsum board contamination rate is 5% and the upper limit is in consideration of fluidity It is judged that the range of 20% can effectively contribute to the strength development of the mixture.
[0023]
[Experimental example]
In the following, experimental examples are shown to describe the features of the present invention more specifically.
Experimental Example The raw consludge used in the table of FIG. 7 was a sludge cake having a moisture content of 235%, and was prepared according to the contents of FIG. For the blending, several points with a moisture content in the range of 235% were selected, and those that could not be kneaded and those that were liquid and could not form a specimen because of large settlement. In addition, the gypsum board waste material was mixed in an external ratio, and the gypsum mixing rate was fixed at 10%. As a kneading method, an omni mixer having a capacity of 5 l (liter) was used. The sludge cake was kneaded for 90 seconds, blast furnace slag fine powder, gypsum and water were added and kneaded for 2 minutes. In the compressive strength test, three cylindrical specimens each having a diameter of 50 × 100 mm were prepared and subjected to tests after 3, 7, 14, 21, 28 days of curing at 20 ° C. and 40 ° C. in water.
Results and discussion Fig. 3 and Fig. 4 show the experimental results. In the case of no gypsum board waste mixed, in order to obtain a compressive strength of 8 N / mm2 or more at a standard curing material age of 7 days, the water content W is reduced to about 40 wt% or less, the amount of sludge cake used is reduced, and the blast furnace slag fine powder It is necessary to increase the amount used. On the other hand, when the gypsum mixing rate is 10%, the water content W is about 50-60 wt% or less, the amount of blast furnace slag fine powder used is less than that without gypsum mixing, and the amount of sludge cake used is increased accordingly. You can see that
[0024]
As described above, the processing method of the raw consludge of the present invention described above into the stable type or the waste according to the stable type and the processed waste are not limited to the above experimental examples.
[0025]
【The invention's effect】
As described above, according to the raw consludge stable type of the present invention or the processing method into the waste conforming to the stable type, the processing waste or the composition setting method of the element, the sludge solids of the raw consludge with the predetermined relational expression The main blending element in which the mass, moisture, and blast furnace slag fine powder are related by their mass fraction, and the sub-mixing element made of waste gypsum are used as the blending material, and the waste gypsum is obtained by a predetermined relational expression. As the amount of 5 to 20 (wt%) based on the total mass of sludge solids and ground granulated blast furnace slag, it is mixed into the main blending element and kneaded, and the raw consludge is treated as a stable type or as a waste conforming to a stable type. Because it is processed, the ready-mixed sludge can be cured at a very low cost and has the same performance as mortar that has been solidified without increasing the processing costs of concrete manufacturers and construction companies. Machining can be treated as, it is possible to prevent the ground water infiltration and environmental pollution harmful substances such as hexavalent chromium by illegal dumping simultaneously. In particular, since the relational expression between each mass fraction of the main blending elements and each mass fraction and the amount of waste gypsum determined by external blending are determined, even non-dehydrated raw consludge with a moisture content of about 1000% It can be processed in principle.
[0026]
At that time, by setting the mass fraction W of water as 30 to 60 (wt%) with respect to the total mass fraction, the amount of blast furnace slag fine powder used is as low as possible and as much as possible It is possible to secure a sludge treatment amount and further specify a range that maintains a desired strength.
[0027]
More preferably, the mass fraction Sd of the sludge solid content is 15 to 25 (wt%), the mass fraction W of the water is 60 to 40 (wt%), and the mass fraction Sg of the blast furnace slag fine powder is 25 to 35. By setting (wt%), it is possible to dispose as a stable waste while maintaining a compressive strength of 8N / mm2 or more, the processing cost is low, and the economic burden on concrete manufacturers and construction companies As a result of being light and proceeding with the treatment, environmental problems due to groundwater contamination, illegal dumping, etc. or troubles with the surrounding residents are reduced, and problems related to the treatment of raw consludge can be solved.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram showing the relationship among various blending elements according to an embodiment of a stable type of raw consludge of the present invention or a processing method for waste according to a stable type.
FIG. 2 is a diagram showing a triangular component graph showing a relational expression of main blending elements.
FIG. 3 is a diagram showing experimental results using a triangular component graph with a gypsum board waste material mixing rate of 10%.
FIG. 4 is a diagram showing experimental results by a triangular component graph in the case of no gypsum board waste mixed.
FIG. 5 is a graph showing the relationship between the gypsum board waste material mixing ratio and the compressive strength.
6 is a graph showing the relationship between the gypsum board waste material mixing rate and the compressive strength under other conditions different from those in FIG. 5;
FIG. 7 is a diagram showing the contents of materials used in experimental examples according to the embodiment.
FIG. 8 is a diagram showing distribution of usage blends in an experimental example according to the embodiment.
[Explanation of symbols]
Sd Sludge solid content W Moisture Sg Blast furnace slag fine powder

Claims (6)

A method for processing raw consludge into a stable type or a waste according to a stable type,
A main blending element comprising sludge solids of raw consludge to be treated, moisture (including water content and water content contained in the raw consludge), and ground granulated blast furnace slag, each of the main blending elements The mass fraction of the ground granulated blast furnace slag with respect to the sum of the mass fractions Sd, W, Sg is distributed so as to be set according to the relationship of the following formula (A):
By mixing the main blending element with a sub-mixing element consisting of 5 to 20 (wt%) waste gypsum with respect to the total mass of the sludge solid content determined by the formula (A) and the blast furnace slag fine powder, A method of processing raw sludge into stable or stable waste, characterized in that the sludge is processed as stable or stable waste.
(Formula A) Sg = 100−W (1 + 1 / α) [wt%] {however, moisture content α = W / Sd} The processing method to the waste according to the stable type or the stable type | mold of the raw consludge of Claim 1 with which the mass fraction W of the water | moisture content was set to 30 thru | or 60 (wt%) with respect to the said mass fraction total. The mass fraction Sd of sludge solids is 15 to 25 (wt%), the mass fraction W of water is 60 to 40 (wt%), and the mass fraction Sg of the blast furnace slag fine powder is 25 to 35 (wt%). The processing method to the waste according to the stable type | mold of the raw consludge of Claim 1 or 2 set to these, or a stable type | mold. The strength of the work piece corresponding to each mass fraction of the main compounding element is set in relation to the formula (A), and the predetermined mass of waste gypsum mixed is fixed, and the main compounding element is fixed to each side of the triangle Each of these elements is assigned and their mass fraction scales are arranged on each side, and at the intersection of parallel lines along the adjacent sides, the target exceeding the predetermined strength and the target not exceeding The processing method to the waste according to the stable type or the stable type | mold of the raw consludge in any one of Claim 1 thru | or 3 discriminated by the triangular component graph displayed by distinguishing. A processing waste according to a stable type or a stable type of raw consludge processed by the processing method according to any one of claims 1 to 4. For the total mass fractions Sd, W, Sg of the sludge solid content, moisture (including the water content and water content contained in the raw con sludge) and the ground granulated blast furnace slag to be treated The mass fraction of the ground granulated blast furnace slag is obtained by the following formula (A), and the waste of 5 to 20 (wt%) with respect to the sum of the sludge solid content and the mass of the ground granulated blast furnace slag obtained by the formula (A) The gypsum is mixed with sludge solids of the mass determined by the formula (A), moisture (including water content and water content in the raw consludge), and blast furnace slag fine powder. A method for setting the composition of each element when processing as a stable type or a waste conforming to the stable type.
(Formula A) Sg = 100−W (1 + 1 / α) [wt%] {however, moisture content α = W / Sd}

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