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1. Sodium based bentonite

Microscopic mechanism of action (deep expansion): The core component of sodium based bentonite is montmorillonite layered silicate mineral, with a crystal structure of a layered stacking structure of double layered silicon oxygen tetrahedra sandwiched by a layer of aluminum oxygen octahedra, and the interlayer is rich in exchangeable sodium ions. After encountering water, water molecules quickly infiltrate into the gaps between crystal layers, causing significant swelling and dissociation of the crystals, peeling off the stacked thick sheets into nanoscale ultra-thin sheet-like chips. The positive charge is carried on the chip end face and the negative charge is carried on the plate surface, forming a stable edge surface electrostatic bonding three-dimensional gel grid in the glaze slurry. This grid structure has excellent low shear yield value and can rigidly lift high-density heavy particles such as zircon powder, melt powder, quartz powder, etc. in a static state; Under the high shear action of stirring, pumping, glazing, and spraying, the colloidal network instantly breaks and deconstructs, causing a rapid decrease in the viscosity of the glaze slurry and a significant increase in fluidity; After the shearing disappears, the mesh quickly recovers, achieving a reversible thixotropic rheological effect. At the same time, it can moderately improve the density and basic strength of the dry glaze layer, which is the core inorganic rheological substrate for preventing settling and anti sagging of glaze slurry. Strict differentiation is required: Calcium based bentonite is absolutely prohibited from being used in glaze slurry systems. Its interlayer calcium ion hydration and swelling ability is extremely poor, and it cannot form an effective colloidal network. It not only has no suspension effect, but also introduces hard particles and damages the stability of glaze slurry.

Core advantages:

① Strong thixotropic performance and high low shear yield value, it is the category with the strongest suspension ability for heavy powder among the four major suspension agents. It can completely solve the problems of hard settling, layering, and supernatant of zirconium white glaze and high melting block glaze. It can remain in a soft settling state after 24 hours of standing and has good redispersibility;

② The high-temperature loss on ignition is extremely low, with no residual organic carbon. Within the normal addition range, there will be no defects such as bubbles, pinholes, or dullness during firing, and it has no negative impact on the basic gloss and flatness of the glaze surface;

③ It has a certain bonding and reinforcement effect, which can improve the overall hardness of the dry glaze layer and reduce the problem of slight powder and glaze peeling after glaze application;

④ High cost-effectiveness of raw materials, strong procurement popularity, suitable for large-scale production of ceramic tiles to reduce costs;

⑤ Colloidal stability is strong, less affected by small temperature fluctuations, and has a high fault tolerance rate for mass production in all seasons. The measured suspension reinforcement effect of 1% sodium based bentonite can effectively replace the suspension stabilization effect of 5-10% kaolin without significantly changing the chemical composition and firing system of the glaze.

Deadly Shortcomings and Production Problems:

① The ion sensitivity is extremely high, and it is extremely sensitive to the hardness of water quality and the electrolyte of the gelling agent. Ca ² ⁺ and Mg ² ⁺ in hard water can displace interlayer sodium ions, causing the colloidal network to collapse instantly and the suspension performance to fail abruptly; Excessive sodium hexametaphosphate and sodium tripolyphosphate debonding agents can compress the colloidal double layer, directly damaging the chip bonding structure and resulting in typical drawbacks such as “viscosity compliance and severe settling”;

② The tolerance rate of the addition amount is narrow, and excessive addition will lead to the thixotropy and elasticity of the glaze slurry being too strong, presenting a jelly like gel state. The leveling property of glaze application is extremely poor, and the glaze ripple, orange peel and uneven thickness are very easy to appear;

③ The drying shrinkage rate is high, and under high addition, the internal stress of the dry glaze layer increases dramatically, causing drying defects such as glaze cracking, curling, and corner peeling;

④ The content of iron impurities in ordinary industrial grade bentonite is relatively high. When used for light colored glaze, transparent glaze, and colored glaze, it is prone to darkening, local discoloration, black spot particles, and interference with the pure color of the glaze surface;

⑤ The pre hydration requirements are strict, and direct feeding of dry powder is prone to agglomeration and formation of fish eye particles, which cannot exert a suspension effect and can also cause defects in the glazed particles.

Accurate addition amount (glaze powder dry basis): 0.5% -1.5% for conventional glaze systems; The upper limit of high melting block and low kaolin clay free system is strictly controlled within 1.5%; Ordinary clay based glaze can be relaxed to 2.0%; Light colored and transparent glaze is strictly controlled at 0.5% -1.0% to avoid the influence of iron impurities.

Exclusive adaptation scenarios and absolutely prohibited scenarios: adaptation to wall and floor tiles with zirconium white glaze, high-density melt block glaze, thick glazed process, large storage tank glaze slurry, industrial mass production of ordinary colored glaze; Absolutely prohibit high-end transparent glaze, ultra white artistic glaze, high-precision light colored glaze, and impurity free high-purity glaze system.

2. Magnesium aluminum silicate

Microscopic mechanism of action: Magnesium aluminum silicate is an artificially synthesized high-purity sheet-like silicate colloidal mineral with a uniform and regular crystal structure, controllable particle size, and no natural mineral impurity defects. After encountering water, it uniformly dissociates into nanoscale ultra-thin sheet-like chips, and through precise edge charge overlap, constructs a fine, uniform, and highly stable flexible colloidal three-dimensional network. Compared with the rigid gel network of bentonite, the magnesium aluminum silicate gel network is more flexible and the thixotropic recovery is more balanced, which can stabilize and lift heavy glaze powder without excessively improving the elasticity of glaze slurry; Colloidal charge distribution is uniform, ion exchange activity is mild, and the tolerance to electrolytes and hard water is significantly better than that of ordinary bentonite. At the same time, the chip has a large specific surface area and uniform adsorption, which can evenly wrap the glaze particles, avoid the aggregation and enrichment of pigments, and ensure the uniform and stable color development of the glaze slurry.

Core advantages:

① High purity, extremely low iron impurity content, excellent whiteness, will not interfere with the color development of light, transparent, and colored glazes, without black spots, impurities, or darkening problems. It is the only inorganic suspended mineral suitable for high-end glaze systems;

② The thixotropic property is balanced, without extreme gel phenomenon, the glaze slurry rheology is soft, giving consideration to anti settlement and glazing leveling, and the flatness and smoothness of the glaze surface are far higher than those of the bentonite system;

③ Excellent redispersibility, long-term standing only forms extremely soft sediment, and can be restored to a uniform state with slight stirring, without clumping or dead materials;

④ Extremely low loss on ignition, excellent thermal stability, no residue or decomposition impurities during high-temperature firing, and does not affect the transparency and glossiness of the glaze surface;

⑤ The batch stability is extremely strong, and the artificial synthesis process avoids the problem of component fluctuations in natural mineral sources. The color difference and rheological fluctuations in mass production are minimal;

⑥ The dry glaze layer is dense and uniform, with low shrinkage stress, and there is basically no drying cracking or curling defects.

Shortcomings and production precautions:

① The raw material cost is significantly higher than that of ordinary sodium based bentonite, and large-scale low-end production will increase the formula cost;

② Still possessing electrolyte sensitivity, ultra-high doses of demulsifier will still weaken the colloidal network, and the amount of demulsifier added needs to be controlled;

③ Strict requirements are placed on the pre hydration process. Directly adding dry powder to the glaze slurry will quickly agglomerate, forming difficult to disperse micro particles that affect the smoothness of the glaze surface;

④ The upper limit of yield value is slightly lower than that of high-purity bentonite, and ultra-high specific gravity heavy glaze slurry needs to be reinforced with a small amount of compound additives to enhance the suspension effect.

Accurate addition amount (glaze powder dry basis): Conventional high-end glaze 0.3% -0.8%; High density color glaze and thick coating glaze have an upper limit of 1.2%; Transparent ultra white glaze is strictly controlled with a low addition amount of 0.3% -0.5%.

Exclusive adaptation scenarios and prohibited scenarios: Suitable for high-end transparent glazes, ultra white glazes, artistic ceramic color glazes, high-end wall tile surface glazes, precision printing glazes, and export grade glazes with extremely high requirements for glaze surface smoothness and color consistency; Prohibit low-end low-cost ordinary glaze systems (cost redundancy) and ultra-high electrolyte excessive glaze slurries.

3. Concave convex rod soil

Microscopic mechanism of action (deep expansion): Attapulgite is a natural needle shaped fiber mineral containing water magnesium aluminum silicate, with a microscopic morphology of nanoscale slender fiber crystals, which is different from the sheet-like structure of bentonite and magnesium aluminum silicate. After encountering water, the fibers are fully dispersed and stretched, relying on the interweaving, interweaving, and overlapping of fibers to form a three-dimensional network support structure. There is no dependence on electrostatic overlapping, and the ion tolerance is extremely strong. Its suspension support comes from the interwoven skeleton of physical fibers, rather than the action of colloidal charges, so it is minimally affected by electrolytes and calcium magnesium hard water ions. It is the category with the best salt and hard water resistance among inorganic suspension agents, and can stably maintain rheological and suspension effects in high ionic strength glazes.

Core advantages (exclusive for harsh working conditions):

① The ability to resist electrolytes and hard water far exceeds that of bentonite and magnesium aluminum silicate, making it suitable for mass production conditions with poor water quality, high addition of demulsifiers, and excessive ion concentration. It completely solves the problem of ion instability and settling in conventional suspension agents;

② The fiber network structure has strong stability and is not prone to collapse when stored for a long time. The glaze slurry layering and settling rate of the storage tank are significantly reduced when stored for a long time;

③ The colloidal elasticity is soft, and the excessive gel problem of bentonite will not occur. The glazing leveling property is excellent, and the glaze surface flatness is high;

④ Good thermal stability, small fluctuations in rheological properties under temperature fluctuations throughout the four seasons, and excellent batch stability;

⑤ Low loss on ignition, normal addition without firing defects, suitable for most conventional glaze systems.

Shortcomings and production drawbacks:

① The recovery speed of thixotropy is slow, and the reconstruction of the grid structure lags behind after shearing. High flow rate glazing and rapid glazing processes are prone to slight glaze sagging and glaze streaks;

② The purity of high-quality mineral sources varies greatly, and low-end concave convex clay has high impurity content and contains fine hard particles, which can easily cause needle points and particle defects on the glaze surface, affecting the smoothness;

③ Fiber has strong adsorption properties, and excessive addition can slightly adsorb pigments, resulting in lighter color development and decreased saturation of light colored glazes;

④ The yield value is relatively weak when used alone, and the ultra heavy zirconium glaze system needs to be reinforced with bentonite to enhance the suspension effect.

Accurate addition amount (glaze powder dry basis): Conventional electrolytes are higher than glaze slurry by 0.4% -1.0%; The upper limit of long-term static storage of glaze slurry is 1.5%.

Exclusive adaptation scenarios and prohibited scenarios: adaptation to hard water quality in the factory area, high electrolyte glaze slurry with high dosage of debonding agent, long-term storage of glaze slurry in storage tanks, ordinary exterior wall tile glaze, and economical mass-produced glaze materials; Prohibit the use of ultra-high smoothness transparent glaze, precision artistic glaze, and ultra-thin spray glaze technology.

4. Cellulose ether

Microscopic mechanism of action: CMC, HPMC, and HEC are all water-soluble polymer cellulose derivatives, with long molecular chains rich in hydrophilic hydroxyl and ether bond groups. Fully expand and diffuse in glaze slurry water, significantly increase the viscosity of the aqueous system through molecular chain entanglement and hydrogen bonding network cross-linking, increase particle settling resistance, and achieve the effect of delaying settling. Different from the thixotropic yielding suspension mechanism of inorganic minerals, cellulose ether does not have a rigid colloidal framework and plays a core role in viscosity blocking settlement; At the same time, molecular chains can adsorb and encapsulate glaze particles and the surface of the body, forming a flexible bonding interface that has multiple effects such as water retention, thickening, bonding, and anti powdering. It is the core reinforcing agent for the dry state performance of glaze slurry. Among them, CMC has the highest cost-effectiveness and the strongest thickening effect; HPMC has better water retention and temperature resistance; HEC has high purity and minimal color influence, making it suitable for high-end glaze systems.

Core advantages:

① Excellent bonding performance, which can significantly improve the density and mechanical strength of the dry glaze layer, completely solving the problems of powdering, glaze peeling, abrasion, and delamination during transportation after glaze application;

② The water retention effect is outstanding, which can delay the drying rate of the glaze layer and avoid dry cracking, peeling, and uneven thickness caused by rapid drying of thick glaze layers;

③ Improve the film-forming properties of glaze application, allowing the glaze slurry to spread more evenly on the surface of the body, enhancing the smoothness of glaze pouring and spraying, and reducing orange peel and glaze leakage defects;

④ Excellent water solubility, the dissolved system is uniform and transparent, without mineral particles or impurities, and does not affect the fineness of the glaze surface;

⑤ It can evenly disperse pigment particles, reduce pigment agglomeration, and assist in improving hair color uniformity and glaze softness.

Fatal Shortcomings and Burning Defects:

① Without an efficient thixotropic yield value, relying solely on viscosity to delay settling cannot suspend high-density heavy powders such as zircon powder alone. The use of high-density glaze slurry alone will inevitably result in hard precipitation;

② Belonging to organic polymer substances, high-temperature firing can lead to thermal decomposition, oxidation, and firing loss. Excessive addition can result in residual trace amounts of carbon and gas inside the glaze layer, causing fatal firing defects such as pinholes, bubbles, pockmarks, and glaze loss of gloss;

③ High pH sensitivity, molecular chains are prone to degradation and breakage in strong acid and alkali environments, resulting in a sharp drop in viscosity and ineffective bonding and suspension effects;

④ Poor temperature resistance, high temperature storage tanks in summer are prone to biodegradation and viscosity decay, leading to fluctuations in batch stability;

⑤ Sensitive to metal ions, high calcium magnesium hard water systems are prone to flocculation failure and cannot be compounded with cationic additives.

Accurate addition amount (glaze powder dry basis): ordinary glaze CMC 0.1% -0.5%; High end transparent glaze and ultra white glaze are strictly controlled with an extremely low addition amount of 0.1% -0.2%; HPMC/HEC can be substituted in the same proportion and adapted to high-end systems. Excessive addition is strictly prohibited to prevent burning defects.

Exclusive adaptation scenarios and prohibited scenarios: Suitable for various glaze spraying and pouring processes, all glaze systems can be used in trace amounts to enhance dry strength; It is absolutely prohibited to use it alone for heavy zirconium glaze and high melting block thick glaze systems; High end transparent glaze and ultra bright glaze strictly reduce the addition amount to avoid defects such as loss of bubbles during firing.