44 results about "Reactive magnesia" patented technology

Novel hydraulic cements are disclosed that include reactive magnesium oxide prepared by low temperature calcination. The cements can be formulated to suit a large number of applications with various setting times, strength and levels of sustainability either by adding iron salts such as ferrous sulfate or blending with other compatible faster setting hydraulic cements such as Portland cement or by using both methods.The compositions are able to incorporate relatively large amounts of low cost pozzolans such as fly ash to advantage as well as wastes. Many excellent properties are exhibited and in particular good comprehensive strength and resistance to sulfates is able to be achieved.

The invention discloses a green low-carbon curing agent for soil curing. The soil curing agent is characterized by comprising granulated blast furnace slag micro powder and exciting agent, wherein the exciting agent comprises active magnesia, the exciting agent is 30 to 5 percent of the total mass of the soil curing agent, and the granulated blast furnace slag micro powder is 70 to 95 percent of the total mass of the curing agent. The exciting agent comprises slaked lime, wherein the slaked lime is 10 to 90 percent of the mass of the active magnesia. The exciting agent comprises calcined lime, wherein the calcined lime is 7 to 66 percent of the mass of the active magnesia.

The invention provides high-early-strength basic magnesium sulfate cement and a preparation method thereof. The preparation method includes: mixing first active magnesium oxide, a dispersing agent, afirst additive and magnesium sulfate aqueous solution to obtain emulsion; mixing the emulsion with second active magnesium oxide and a second additive, and hardening to obtain the high-early-strengthbasic magnesium sulfate cement. By adoption of the preparation method, the high-early-strength basic magnesium sulfate cement can be prepared, and product production efficiency can be greatly improved.

The invention discloses a multifunctional consolidation plugging agent for drilling fluid, which comprises the following components in mass percentage: 45-60% of inorganic mineral materials, 4-5% of fibers, 15-20% of curing agent, and filter aids 5-10%, 3-5% retarder, 5-10% expansion agent, 3-5% dispersant; the inorganic mineral material is that the particle size is 200 mesh ash calcium and active magnesium oxide according to the weight ratio of 0.5: 1 or a 1:1 mix. The fiber is a brucite fiber with an aspect ratio of 10-50:1 and a diameter of 0.5-15um. The components are uniformly mixed to obtain a multifunctional consolidation plugging agent for drilling fluid. The lost circulation agent uses clean water or water-based drilling fluid as the base fluid to directly prepare the lost circulation slurry. It can adopt three construction methods: while drilling, high filtration loss, and overall consolidation; it is easy to use, no need to clean the tank and change the drilling tool assembly; and the settlement stability is high. If clean water is used as the base fluid, it can be directly aggravated to the required density. .

The invention relates to a device for producing high-activity magnesia by using magnesite tailings, comprising a gas-fired hot blast stove, a filter cake feeder, a flash dryer, a cyclone separator, a bag filter, a preheater, a screw feeder and a flash dryer. Cyclone dynamic calciner, gas-solid separator, silo, air cooling system and product silo, gas hot blast stove is connected to filter cake feeder, filter cake feeder is connected to flash dryer, and the outlet of flash dryer is connected to the first Cyclone separator and the first bag filter, the first bag filter is connected to the preheater, the preheater is connected to the flash cyclone dynamic calciner through the screw feeder, and the outlet of the flash cyclone dynamic calciner is connected to the gas-solid separator , the gas-solid separator is connected to the silo and the second bag filter respectively, the silo is connected to the air cooling system, the air cooling system is connected to the second cyclone separator and the second bag filter, and the second bag filter is connected to the product silo , the flash swirl dynamic calciner introduces the waste heat into the flash dryer.

The invention provides a preparation method of modified magnesium sulfate cement. The method is as follows: (1) weigh concentrated sulfuric acid, superfine fly ash, magnesium oxide and water according to a certain proportion; (2) add concentrated sulfuric acid Prepare a dilute sulfuric acid solution in a certain amount of spare water, then add ultrafine fly ash, and stir to obtain activated modified ultrafine fly ash; (3) Slowly add 10-20% of spare magnesia to the obtained In the mixture, adjust and stir to fully dissolve the active magnesium oxide to obtain a mixture of fly ash and magnesium sulfate solution; (4) Weigh a certain amount of admixture (add the remaining water, stir and dissolve at room temperature, and then add it to the mixture obtained in step (3). In the mixture, continue to add the remaining magnesium oxide, and stir for 30-60 min to obtain a thick magnesium sulfate cement slurry; the magnesium sulfate cement obtained by the present invention has a compressive strength of 66.96 MPa in 28 days, and the operation is simple and the cost is low , easy to realize industrialization.

The invention discloses a method for treating a subgrade of a highway in a frozen soil region. The method comprises the following steps: a, thawing a frozen soil subgrade in a frost line in advance; b, excavating all thawed soil; c, laying a layer of coarse-grained soil and a reversed filter layer at the bottom of an excavation layer, and laying lime waterproof layers and gravel expansion guide layers on two sides; d, filling activated magnesia carbonized and cured sludge soil layer by layer and performing tamping reinforcement; e, compacting filled embankment filling soil and setting a coarse-grained soil layer containing an XPS insulation board below a pavement structure; f, setting waterproof protecting feet on two sides of an embankment respectively. Subgrade pre-thawing, filling treatment and soft soil carbonization and curing technologies for the frozen soil region are fully combined, the frozen soil subgrade is effectively reinforced, the engineering problems of refreezing and frost heaving of subgrade soil are well solved, non-uniform settling of the subgrade is further reduced, and the problem of secondary damage of the highway in the cold region is reduced greatly. The method has the advantages of being economic, environmentally friendly, safe, efficient, high in controllability, easy to operate and the like.

The invention discloses a method for solidifying tailings sand based on active magnesia microorganisms and its products. Active magnesia is used as the basic curing agent, and microbial technology is used to provide CO required for carbonization. 2 and reduce the heavy metals in the tailings sand, making full use of the advantages of magnesium oxide solidified soil technology and microbial technology, using the carbonate ions produced by the hydrolysis of urea by Bacillus to carbonize the magnesium oxide solidified soil, improving the strength of the brick body, and using The extracellular complexation, extracellular precipitation and intracellular accumulation of heavy metals by microorganisms can reduce the content of heavy metal ions. The method has the advantages of simple process, no sintering, short construction period, high strength, environmental protection, can realize win-win of environmental benefit and economic benefit, and has good application prospect.

The invention relates to an expander for alkali slag concrete, composed of activated magnesium oxide mixture and a mixture of one or two of alkali metal carbonate and alkali metal bicarbonate. The invention also relates to a method of using the above expander, comprising a method of use when solid sodium hydroxide is used as an activator, including: preparing raw materials, mixing the raw materials, adding water and stirring to obtain alkali slag concrete mixture, and also comprising a method of use when liquid water glass and dissolved sodium hydroxide are used as activators, including: preparing raw materials, pretreating and stirring the raw materials, and stirring well to obtain concrete mixture.

The invention provides a method for evaluating the hydration activity of magnesium oxide expansion agent; the method is to use an isothermal calorimeter to test the hydration heat curve of magnesium oxide powder in deionized water and the average heat release per unit time to evaluate Hydration activity of magnesia expansion agent; if the average heat release per unit time q in 24h > 25J / h, it is high activity magnesia, if 15J / h≤q≤25J / h, it is medium activity magnesia, if q<15J / h, it is low-activity magnesium oxide; the method of the present invention can comprehensively observe the hydration history of the magnesium oxide expansion agent according to the hydration heat curve, and determine the magnesium oxide expansion agent quickly and accurately by calculating the heat release per unit time within 24h. The hydration activity of magnesium oxide expansion agent has a more accurate effect on predicting the expansion performance of magnesia expansion agent in the alkaline environment of cement concrete.