Study On Comprehensive Utilization Technology Of Marble Tailings In Shimian County

There is a large marble resource reserves in China,but the way to develope and utilize is single.The tailings accumulation is large,however,the degree of resource utilization is low.This project takes the marble tailings in Shimian County,Sichuan Province as the research object,and the samples are subjected to pretreatment such as washing,sorting and crushing.The obtained samples are analyzed for mineralogical properties.According to the composition characteristics of the raw materials,they were used to prepare aragonite whiskers;purify desiliconize;preparation of artificial stone,the optimized process conditions were obtained.The entire process research has great environmental benefits and can generate high economic value.It provides experimental reference and utilization ideas for solving marble tailings storage and promoting resource utilization.White marble talings was obtained by sieving,which particle size is from 0.9 to 3 mm,its whiteness was 66.8%,which phase was calcite,and the impurity content was above 0.65%.The effects of calcination temperature and holding time on the activity of quicklime were studied.When the temperature was 1000?,the calcination was completed in 25 minutes.When the temperature was 1100?,the decomposition stability was achieved in 10 minutes.The activities of the obtained quicklime were 386 and 415 respectively.When the calcination temperature is 1000?.And the lasting time is within 30 minutes,as the holding time increased,the activity of the quicklime obtained by the calcination increases,reaching a maximum of420 at 30 minutes.When the calcination temperature is 1100?and the lasting time is within20 minutes,the activity of the quicklime obtained by the calcination first increases and then decreases.When the lasting time is 8 minutes,the activity of the obtained quicklime reaches the maximum,which is 428.The aragonite whiskers were prepared by the carbonization method.At a reaction temperature of 80°C,a MgCl₂ solution concentration of 0.5 mol/L,a CO₂ aeration rate of 50 mL/min,and a lime emulsion concentration of 0.18nom/L,the whisker length of the obtained sample was about 30?m.The diameter is 1³?m,and its aragonite crystal content is 93%.At the same time,the filtrate obtained by the reaction is recycled,and the filtrate mixed turbid liquid and the upper clarified liquid are respectively taken for reaction.It was recycled to fourth times at most for better result.The turbidity was circulated from the first time to the fourth time,and the aragonite crystal content of the obtained samples was 94%,96%,95%,and 91%,all of which were above 90%.The length of the obtained aragonite whisker is 20³0?m,and the diameter of the middle is 1³?m.The filtrate was circulated from the 1st to the 4th,and the aragonite crystal content of the obtained sample was 92%,85%,96%,and 95%,the whisker length was 20³5?m,and the diameter of the middle was 1²?m.Adding an appropriate amount of PAM?polyacrylamide?at the same time is beneficial to increase the length of aragonite whiskers.When the amount of PAM is 0.05g/L,the length of the obtained aragonite whiskers is 60⁷0?m,and the diameter of the middle is 3⁵?m.The whisker aspect ratio is14¹9,the whiteness of the sample is 88%,and the proportion of aragonite can reach 91%.The study found that the intermittent aeration method during the carbonization reaction is beneficial to the growth of whiskers.The starting point and duration of intermittent ventilation were studied separately,and the intermittent ventilation reaction was repeated to verify its effect and mechanism on whisker growth.It was found that the ventilation was paused for 10minutes after stable ventilation for 40 minutes,and then the stable ventilation was continued.the length is 80⁹0?m,the diameter is 7⁹?m,the whisker aspect ratio is 10,the aragonite phase ratio is 88%,and the verification is repeated for 3 times.It showed that the intermittent ventilation method is indeed conducive to the growth of whiskers.Analyzing the reason,this is related to the fact that the fine aragonite crystals?nucleus?can dissolve and grow to large crystals during intermittent aeration,which reduces the number of crystal nucleation,what is beneficial to the subsequent reaction of new ions.On the basis of continued growth,the macroscopic manifestation is an increase in crystal size,and the crystal length and diameter have increased compared to the stable aerated sample.Sieve to obtain white fine-grained marble tailings with a particle size of less than 0.9mm,whiteness is 76.7%,hydrochloric acid insoluble content is 0.28%,the main component of the insoluble matter is SiO₂,and the phase is quartz,accompanied by a little hematite,Muscovite and pyrophyllite.In order to reduce the content of hydrochloric acid insolubles to the requirements of high-grade calcium carbonate raw materials such as toothpaste and medicinal materials,the content of hydrochloric acid insolubles is?0.2%.The alkali roasting and water immersion method is used to promote the reaction between silica and alkali in the sample to form soluble Silicate was leached.The effects of reaction temperature,amount of alkali and reaction time on the desiliconization effect were studied.It was found that when the reaction temperature is 700°C,the content of hydrochloric acid insolubles in the sample can be reduced to meet the requirements.When the amount of alkali is 20%,the content of hydrochloric acid insoluble matter in the obtained sample is less than 0.15%.The reaction time reached 30minutes and above,the alkaline melting reaction in the sample was basically complete,and the content of insoluble matter in hydrochloric acid changed little.The remaining marble tailings mud was used for the preparation of artificial stones.It was found that when the sample was mixed with aluminum hydroxide and the aluminum hydroxide accounted for a large proportion,the resulting sample produced more bubbles and had a lower compressive strength,ranging from 1³MPa.At the same time,reducing the amount of resin will cause uneven mixing of the sample,bad coagulation,and affect the curing effect.The powder and granules in the tailing mud sample were mixed in different proportions,and an appropriate amount of resin was added at the same time.As the proportion of the particles in the raw material increased,the compressive strength of the obtained sample gradually increased.When the ratio of sludge and particles is 5:5,the compressive strength of the obtained sample is increased to 78 MPa.The analysis is that the mud slag and the particles belong to the marble tailings,which have good compatibility,and that the particles play a skeleton role in the artificial stone,resulting in a significant increase in the compressive strength of the sample.