Method of making board made of lignite ash-slag, wood particles and synthetic adhesive
FlELD OF THE INVENTlON 
     This invention relates to a construction board and the like used in building construction, the method of making and the composition thereof. 
     BACKGROUND OF THE INVENTION 
     Widely available lignite ash-slag, which is a waste product presently of no use, poses an environmental problem. The present invention uses this environmental waste mineral product as a main component in making a construction board, such as a wall panel, isolated panel, floor board, etc. 
     It is conventional to use a construction board made of composite material, such as cement or gypsum mixed with wood particles. However, boards made of these composite materials are not economical and/or have weak or undesirable physical property in comparison with a board of the present invention. As disclosed in Obzornaia News Magazine, Number 2 (1987), manufacturing one cube meter (1 m 3 ) of a cement board consumes the following: 
     cement 770 kg 
     wood 280 kg 
     chemical product 50 kg 
     electrical energy 140-290 kwh 
     thermal energy 400 kcal 
     manufacture (human work) consumption 27 hours. 
     As evidenced above a cement board made from a mixture of cement and wood particles requires a huge consumption of energy and labor in the making thereof. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide a construction board made from a widely available, useless mineral waste product of lignite ash-slag and to solve an important ecological problem. 
     Another object of the invention is to provide a construction board which requires a low energy consumption in manufacturing thereof. 
     Another object of the invention is to provide a construction board of superior physical attributes, in particular, a board which is resistant to acid corrosion and which is water-proof and fire-proof. 
     Another object of the invention is to provide a method for carrying out the above-described object. i.e., the method of making the board. 
     In accordance with the present invention, the above noted objects may be carried out by using a lignite ash-slag mineral waste, waste wood particles and a synthetic adhesive. Since lignite ash-slag is an alkaline product, the board made from lignite ash-slag confers an excellent resistance to corrosion from acids. The lignite ash-slag board is also fire-proof, eliminating the step of a fire-proof treatment, saving manufacturing costs. The present lignite ash-slag board is also water-proof. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A lignite ash-slag construction board of the present invention, hereafter &#34;Logicore board&#34;, is water-proof, fire-proof and corrosion-resistant, as previously mentioned. The components of the Logicore board are lignite ash-slag, waste wood particles and a synthetic adhesive. As previously mentioned, lignite ash-slag is a waste mineral product which is widely available and poses environmental problems, but, to the best of the present inventors&#39; knowledge, has no present use. The present invention solves an important ecological problem by converting this mineral waste product into useful products. 
     Lignite ash-slag is rather alkaline, having 7.5-8 pH. Therefore, lignite ash-slag product is resistant to acid corrosion. Lignite ash-slag has a density of 1.75 g/cm 3  and a large variety of granulation, the preferable granulation having a nominal diameter between 2.8-3.8 millimeter. Sieves or filters can be used to extract the desired granulation. 
     The wood waste products can be any of wood wastes such as splinters, preferably of beech or fir, sawdust and shavings. 
     The synthetic adhesive is based on an adhesive solution formed by widely available urea-formaldehyde resin of P-type and a hardener. The hardener can be obtained by dissolving in water at 23°-30° C. of the components by the weight percent in the order listed below: 
     1 weight % maleic anhydride 
     10 weight % ammonium chloride 
     10 weight % technic urea 
     10 weight % technic ammonia of 25% concentration 
     (69 weight % water). 
     The temperature of the urea-formaldehyde resin poly-condensation, as well as the Logicore board, is relatively low, 155° C. This equates to a low consumption of energy in manufacturing the Logicore board. 
     Two different adhesive concentrations are used between ash-slag and wood waste particles. In particular, the ratio between the resin and the hardener is 9:1 for ash-slag and is 10:1 for waste wood particles. An example of glue preparation is as follows: 
     PREPARATION OF HARDENER SOLUTION 
     1. One gram of maleic anhydride is introduced and dissolved in a 100 ml vessel containing 10 ml of water at 25°-30° C. 
     2. Ten grams of ammonium chloride is introduced and dissolved in the vessel. 
     3. Ten grams of technic urea is introduced and dissolved in the vessel. 
     4. Ten (10) ml of technic ammonia of 25% concentration is introduced into the vessel and mixed. 
     5. Fifty-nine (59 ml) of water at 25°-30° C. is added into the vessel and mixed. 
     6. Homogenize the above mixture. 
     PREPARATION OF THE ADHESIVE SOLUTION 
     For the Lignite Ash-Slag: Mix nine (9) parts of urea-formaldehyde resin of P-type with one (1) part of the hardener obtained above to obtain 9:1 ratio between the resin and the hardener. Water is added as needed to change the viscosity thereof. 
     For the Wood Waste Particles: Mix ten (10) parts of urea formaldehyde resin of P-type with one (1) parts of the hardener obtained above to obtain 10:1 ratio between the resin and the hardener. Again, water is added as needed to change the viscosity thereof. 
     The method of manufacture is quite simple and merely requires conventional equipments such as a mill for brambling lignite ash-slag, a glue mixer, a mixer for mixing ash-slag with glue and wood waste particles with glue, a cold press, a hot press and a cutting device for sizing the board. 
     Lignite ash-slag and the synthetic adhesive obtained above are mixed in a vessel. Wood waste particles and the synthetic adhesive obtained above are mixed in another vessel. The mixture in the two vessels are then mixed together to form a homogenous wet Logicore mixture. Then the mixture is poured into a blanket. Thereafter, the blanket is pressed for about five minutes at a pressure of 15 kgF/cm 2 . Thereafter, the cold pressed blanket is pressed in a hot press at 155° C., the temperature of the urea-formaldehyde resin poly-condensation, at a pressure of 30 kgF/cm 2  for about 20 minutes. The board obtained is cured for 5-7 days, thereafter is cut to the desired size for use as a construction board. 
     The specific consumption for a board having the dimension of 450 mm×450 mm×16 mm is as follows: 
     lignite ash-slag: 2100 gm 
     waste wood particles: 900 gm 
     synthetic adhesive: 350 gm. 
     EXAMPLE 1 
     A Logicore board is made as follows: 
     The weight ratio between lignite ash-slag, wood waste particles and synthetic adhesive is 65:20:15. 
     1. Formation of lignite ash-slag mixture: 2100 gm of lignite ash-slag is mixed at a room temperature (20° C.) with 250 gm of the synthetic adhesive obtained above (9:1 ratio between the resin and the hardener). 
     2. Formation of wood waste particle mixture: 900 gm of wood waste particles is mixed at a room temperature (20° C.) with 100 gm of the synthetic adhesive obtained above (10:1 ratio between the resin and the hardener). 
     3. Homogenization of the lignite ash-slag and wood waste particle mixtures: both mixtures obtained in steps 1 and 2 are mixed to obtain a homogenous Logicore mixture. 
     4. Formation of a blanket: the homogenous Logicore mixture is laid out into a blanket or a mat. 
     5. Cold press: the blanket is cold pressed at a room temperature for about 5 minutes at 15 kgF/cm 2  pressure. 
     6. Hot press: the cold pressed blanket is hot pressed at a temperature of about 155° C. for 20 minutes at 30 kgF/cm 2  pressure. 
     7. Curing: the hot pressed blanket is cured for 5-7 days. 
     8. Cut to size: the board is ready for cutting to desired size using any ordinary wood cutting tool and can then be used thereafter. 
     The physical and mechanical characteristics of the Logicore board are as follows in Table 1 below: 
     
                       TABLE 1                                                     
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                      Units of                                            
Characteristics       Measure  Values                                     
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1     Aspect              --       gray-                                  
                                   black                                  
                                   grits                                  
2     Ash-slag grit (rest on 4 mm                                         
                          %        10                                     
      sieve)                                                              
3     Density             g/cm.sup.3                                      
                                   1.75                                   
4     pH                  pH       7.5-8                                  
5     Solid substance     %        81.84                                  
6     Nontoxic volatile   %        4.35                                   
7     Free carbon         %        13.81                                  
8     Other waste material                                                
                          %        10-15                                  
9     Humidity            %        3-5                                    
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     The bond characteristics are as follows in Table 2 below: 
     
                       TABLE 2                                                     
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                      Units                                               
                      of                                                  
Characteristics       Measure  Values                                     
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1     Viscosity (Ford cup, 8 mm                                           
                          sec      65                                     
      diameter)                                                           
2     Reactivity          sec      85                                     
3     Viable period       hour     &gt;20                                    
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     Table 3 below shows the test results of the strength of the present Logicore board. 
     
                       TABLE 3                                                     
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Test                           Result                                     
denomination                                                              
            Test tubes and procedure                                      
                               daN/cm.sup.2                               
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1   Strength of Test in test-tube of                                      
                                   53                                     
    materials at                                                          
                30 × 5 × 1.55-1.57 cm with                    
    bending tension                                                       
                W-type Monsanto tensiometer                               
2   Strength of Test in test-tube of                                      
                                   55                                     
    materials at                                                          
                30 × 5 × 1.55 -1.57 cm with                   
    bending tension                                                       
                W-type Monsanto tensiometer                               
3   Strength of Test in test-tube of                                      
                                   55                                     
    materials at                                                          
                30 × 5 × 1.55 -1.57 cm with                   
    bending tension                                                       
                W-type Monsanto tensiometer                               
4   Strength of Test in test-tube of                                      
                                   64                                     
    materials at                                                          
                30 × 5 × 1.55 -1.57 cm with                   
    bending tension                                                       
                W-type Monsanto tensiometer                               
5   Strength of Test in test-tube of                                      
                                   64                                     
    materials at                                                          
                30 × 5 × 1.55 -1.57 cm with                   
    bending tension                                                       
                W-type Monsanto tensiometer                               
          Average value =  58                                             
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     Table 4 shows the test results of the thermal conductivity of the present Logicore board. 
     
                       TABLE 4                                                     
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                     Results                                              
Test       Test tubes and           Kcal/                                 
denomination                                                              
           procedure       W(m.K)   mh°C.                          
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1   Thermal    Test in test-   0.313  0.269                               
    conductivity                                                          
               tubes of                                                   
    at 0° C.                                                       
               20 × 6 × 1.54-1.55 cm                          
               with T.M05                                                 
               thermal                                                    
               conductivity test                                          
2   Thermal    Test in test-   0.260  0.224                               
    conductivity                                                          
               tubes of                                                   
    at 0° C.                                                       
               20 × 6 × 1.54-1.55 cm                          
               with T.M05                                                 
               thermal                                                    
               conductivity test                                          
3   Thermal    Test in test-   0.280  0.241                               
    conductivity                                                          
               tubes of                                                   
    at 0° C.                                                       
               20 × 6 × 1.54-1.55 cm                          
               with T.M05                                                 
               thermal                                                    
               conductivity test                                          
4   Thermal    Test in test-   0.322  0.277                               
    conductivity                                                          
               tubes of                                                   
    at 0° C.                                                       
               20 × 6 × 1.54-1.55 cm                          
               with T.M05                                                 
               thermal                                                    
               conductivity test                                          
5   Thermal    Test in test-   0.313  0.269                               
    conductivity                                                          
               tubes of                                                   
    at 0° C.                                                       
               20 × 6 × 1.54-1.55 cm                          
               with T.M05                                                 
               thermal                                                    
               conductivity test                                          
         Average value =                                                  
                       0.297    0.256                                     
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     Table 5 shows the test results of certain physical properties of the present Logicore board. 
     
                       TABLE 5                                                     
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Test         Denomination of test                                         
denomination tubes and procedure                                          
                              Results                                     
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1   Humidity     Test according to STAS                                   
                                   5.54%                                  
                 9492/73 in test tubes of                                 
                 50 × 50 mm                                         
2   Inflation    Test according to STAS                                   
                                  11.5%                                   
                 5884-75 in test tubes of                                 
                 50 × 50 mm                                         
3   Apparent     Test according to BS                                     
                                  16.7 kg/m.sup.2                         
    average      6432-84 in test tube of                                  
    (medium)     50 × 50 mm                                         
    mass in dry                                                           
    condition                                                             
4   Water        Test according to BS                                     
                                  23.7%                                   
    absorption   6432-84 in test tube of                                  
    after 19     50 × 50 mm                                         
    hours of                                                              
    immersion                                                             
5   Apparent     Test according to BS                                     
                                  32.2%                                   
    porosity     6432-84 in test tube of                                  
                 50 × 50 mm                                         
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 BS = British Standard                                                    
 STAS = Rumanian Standard                                                 
 
    
     Table 6 shows the test results of the density of the present Logicore board. 
     
                       TABLE 6                                                     
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             Denomination of test                                         
                                Results                                   
Test denomination                                                         
             tubes and procedure                                          
                                kg/m.sup.3                                
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1   Density in dry                                                        
                 Test in test tube with                                   
                                    1.198                                 
    condition    dimensions of 30 × 6 × 1.54-                 
                 1.55 cm according to STAS                                
                 2160/88                                                  
2   Apparent density                                                      
                 Test according to BS                                     
                                    1.011                                 
    in dry condition                                                      
                 6432-84, chap. 5, in test                                
                 tubes of 50 × 50 mm                                
3   Medium (average)                                                      
                 Test according to BS                                     
                                    1.335                                 
    apparent density                                                      
                 6432-84, chap. 5, in test                                
    in wet condition                                                      
                 tubes of 50 × 50 mm                                
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 BS = British Standard                                                    
 STAS = Rumanian Standard                                                 
 
    
     The present Logicore board uses a waste mineral product which has no present use. By converting useless, considered environmental hazard material into a useful construction board, the present invention solves an important ecological problem. The present Logicore board is easy to produce and importantly is fire-proof. Therefore, it does not require any kind of fire-proofing treatment prior to use. Moreover, the board is resistant to acid corrosion and thus can be used in a corrosive environment. 
     The foregoing is illustrative of the principles of the present invention. Numerous modifications to the method for making the present Logicore board can be readily contemplated by one skilled in the art without departing from the scope and breadth of the present disclosure. For example, the ratio between the resin and the hardener of the synthetic adhesive and the ratio between the components need not be exactly limited to the ones presently disclosed, as other ratios could be contemplated without changing the physical and mechanical properties of the present invention. Moreover, the cold and hot pressure and the time duration of the pressing need not be limited solely to the ones specifically disclosed, as one skilled in the art could have contemplated using other pressure/time variation without any undue experimentation and without departing from the scope and breath of the present invention.